Optical sensor for optical detection and detector

Abstract

To provide an optical sensor capable of maintaining a high performance and stability thereof over a long time.SOLUTION: An optical sensor (110) includes a stack (125). The stack (125) includes a substrate (124), a layer (112) of at least one photoconductive material (114), a cover (116), and electrical contacts (136, 136') which contact the layer (112) of the photoconductive material (114). In a quasi-static nanoindenter measurement of the stack (125), the optical sensor (110) exhibits a Young's modulus at a penetration depth of 100 nm of 75 GPa to 107 GPa, at the penetration depth of 300 nm of 47 GPa to 127 GPa, and at the penetration depth of 1,000 nm of 49 GPa to 119 GPa, and a hardness at the penetration depth of 100 nm of 1.20 GPa to 4.70 GPa, at the penetration depth of 300 nm of 1.60 GPa to 4.60 GPa, and at the penetration depth of 1,000 nm of 1.60 GPa to 8.00 GPa.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to an optical sensor and a detector having such an optical sensor, for optical detection, in particular for the detection of optical radiation, in particular in the infrared spectral range, in particular for sensing at least one of transmission, absorption, emission and reflection provided by at least one light beam, or for determining the position of at least one object, in particular the depth of at least one object or the position of at least one object with respect to both depth and width. Further, the present invention relates to a method for manufacturing an optical sensor and various uses of the optical sensor and the detector. Such devices, methods and uses can be employed in various fields of safety technology, specifically in the form of safety-related devices such as gas sensors, spark sensors or flame sensors. However, further applications, especially in the field of security technology, are also possible.

Background Art

[0002] Various detectors for optically detecting at least one object are known based on optical sensors.

[0003] WO2012 / 110924A1 discloses a detector including at least one optical sensor, the optical sensor showing at least one sensor region. Here, the optical sensor is designed to generate at least one sensor signal in a manner dependent on the irradiation of the sensor region. According to the FIP effect described therein, the sensor signal depends on the geometric shape of the irradiation, in particular the beam cross-section of the irradiation on the sensor region, assuming that the total output of the irradiation is the same. The detector further has at least one evaluation device designated to generate at least one item of geometric information from the sensor signal, in particular at least one item of geometric information regarding the irradiation and / or the object.

[0004] WO2014 / 097181A1 discloses a method and a detector for determining the position of at least one object using at least one lateral light sensor and at least one longitudinal light sensor. Preferably, a stack of longitudinal light sensors is employed, in particular for determining the longitudinal position of an object with high precision and unambiguously. Further, WO2014 / 097181A1 discloses a human machine interface, an entertainment device, a tracking system, and a camera, each comprising at least one such detector for determining the position of at least one object.

[0005] WO2016 / 120392A1 discloses a further type of material suitable as a longitudinal light sensor. Here, the sensor region of the longitudinal light sensor comprises a photoconductive material, and the electrical conductivity in the photoconductive material depends on the beam cross-section of the light beam in the sensor region, assuming the total power of the irradiation is the same. Thus, the longitudinal sensor signal depends on the electrical conductivity of the photoconductive material. Preferably, the photoconductive material is selected from lead sulfide (PbS), lead selenide (PbSe), lead telluride (PbTe), cadmium telluride (CdTe), indium phosphide (InP), cadmium sulfide (CdS), cadmium selenide (CdSe), indium antimonide (InSb), mercury cadmium telluride (HgCdTe; MCT), copper indium sulfide (CIS), copper indium gallium selenide (CIGS), zinc sulfide (ZnS), zinc selenide (ZnSe), or copper zinc tin sulfide (CZTS). Further, solid solutions and / or their doped variants are also possible. Further, a lateral light sensor having a sensor region is disclosed, the sensor region having one layer of a photoconductive material, preferably one layer of a photoconductive material embedded between two layers of a transparent conductive oxide and between at least two electrodes. Preferably, at least one of the electrodes is a split electrode having at least two partial electrodes, and the lateral sensor signal provided by the partial electrodes indicates the x-position and / or the y-position of the incident light beam within the sensor region.

[0006] WO2018 / 019921A1 discloses an optical sensor comprising at least one layer of a photoconductive material, at least two separate electrical contacts in contact with the layer of the photoconductive material, and a cover layer deposited on the layer of the photoconductive material, wherein the cover layer is an amorphous layer containing at least one metal-containing compound. The optical sensor can be provided as an airtight package that provides a high degree of protection against the possibility of degradation by humidity and / or oxygen, despite not being bulky. Further, the cover layer can activate the photoconductive material, and as a result, improve the performance of the optical sensor. Further, the optical sensor can be easily manufactured and integrated into a circuit carrier device.

[0007] Further, European Patent Application 19152511.2 filed on January 18, 2019 discloses an optical sensor comprising a substrate, at least one layer of a photoconductive material applied directly or indirectly to the substrate, at least two separate electrical contacts in contact with the layer of the photoconductive material, and a cover covering the accessible surface of the photoconductive material and the substrate, wherein the cover is an amorphous cover containing at least one metal-containing compound.

[0008] In particular, optical sensors comprising at least one photoconductive material are typically used in safety-related devices such as gas sensors, spark sensors, flame sensors, etc. Further, other types of applications, particularly in the field of security technology, are also possible. Therefore, in order to meet the requirements specific to these application fields, it is desirable to maintain the high performance and stability of the optical sensor over a long period of time. Despite the advantages shown by the above-described devices and detectors, there is still a need for improvement with respect to optical sensors and spatial detectors that are simple, cost-effective, and highly reliable, particularly with regard to the advantages achieved by reactive encapsulation as represented, for example, in WO2018 / 019921A1 and European Patent Application 19152511.2 filed on January 18, 2019, even though they significantly improve the performance and long-term stability of the optical sensor.

[0009] "Band Gap Engineering Applications and Materials Science of Pb x Cd 1-x Se Thin Films: A Study of Their Optical, Electrical, Structural and Local Mechanical Properties", Phys. Status Solidi A 207, No. 8, 1880 - 1886 (2010) describes a novel electrochemical technique for preparing band gap engineered IV-II-VI type ternary solid solution systems of Pb x Cd 1-x Se. We used a self - contained modified electrochemical cell consisting of a Pb anode and a glass cathode coated with a transparent conductive oxide (TCO) containing Pb(CH3COO)2, Cd(CH3COO)2, H2SeO3, and a Na2EDTA solution at an appropriate concentration as the working electrolyte. X - ray diffraction (XRD) pattern analysis confirmed the formation of highly crystalline Pb x Cd 1-x Se, while scanning electron microscopy (SEM) confirmed a uniform deposition with a compact surface morphology. The good rectifying behavior of the TCO / PbxCd 1- xSe heterojunction was established by current - voltage measurements, which indicates the p - type conduction characteristics of the deposited ternary compound. The mechanical properties of such thin films were measured by nanoindentation.

[0010] "Variation of Microindentation Hardness as a Function of Composition in Polycrystalline Solutions of the PbS / PbTe, PbSe / PbTe, and PbS / PbSe Systems" by M.S. Darrow, W.B. White, and R.R. Roy, Journal of Materials Science 4(1969)313 - 319 describes the measurement of Vickers microindentation hardness as a function of composition for polycrystalline solutions of lead chalcogenide systems and its comparison with the dissolution tendencies indicated by the characteristics of the quasi - solidification of the phase diagrams. Each system showed a positive deviation from the linear hardening relationship between the end - member compounds. The most significant hardening was observed for the PbS / PbTe solution; the maximum hardness occurred at about 30 mol% PbTe and coincided with a large solubility gap at the maximum of the solvus (critical point) at about 30 mol% PbTe and about 805 °C. The minimum amount of hardening was observed in the PbS / PbSe system, which showed no elution at low temperatures of 300 °C. The hardness - versus - composition curve was approximately symmetric at the 50 mol% composition. Intermediate between these two systems, the PbSe / PbTe crystalline solution showed an asymmetric hardness / composition curve with a maximum hardness at about 30 mol% PbTe. The partial - phase study indicates the possibility of a maximum of the solvus at 500 - 600 °C on the PbSe - rich side of the figure.

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, the problem addressed by the present invention is to identify an apparatus and method for optical detection that at least substantially avoids the drawbacks of this kind of known apparatus and method.

[0012] In particular, it is desirable to provide an optical sensor comprising at least one photoconductive material and a detector for optical detection comprising such an optical sensor, where the high performance and stability of the optical sensor can be maintained over a long period to meet the specific requirements for applications such as safety - related devices such as gas sensors, spark sensors, or flame sensors, and similarly for applications in the field of security technology.

Means for Solving the Problems

[0013] This problem is solved by the present invention having the features of the independent claims. Advantageous developments of the invention, which can be implemented individually or in combination, are indicated in the dependent claims and / or in the following description and detailed embodiments.

[0014] As used herein, the terms "having", "comprising", and "including", and their grammatical variations, are used in a non-exclusive manner. Thus, the expression "A has B", as well as the expressions "A comprises B", or "A includes B", can refer both to the fact that, in addition to B, A includes one or more further components and / or elements, and to the case where, in addition to B, no other components and / or elements are present in A.

[0015] In a first aspect of the present invention, an optical sensor is disclosed. Herein, the optical sensor according to the present invention has a stack, and the stack a substrate, at least one layer of a photoconductive material applied to the substrate, a cover covering the accessible surface of the layer of the photoconductive material, and at least two separate electrical contacts spatially separated from the stack and in contact with the layer of the photoconductive material. The optical sensor, in a quasi-static nanoindentation measurement of the stack, has a Young's modulus of 75 GPa to 107 GPa at an indentation depth of 100 nm, of 47 GPa to 127 GPa at an indentation depth of 300 nm, of 49 GPa to 119 GPa at an indentation depth of 1000 nm, and a hardness of 1.20 GPa to 4.70 GPa at an indentation depth of 100 nm, of 1.60 GPa to 4.60 GPa at an indentation depth of 300 nm, of 1.60 GPa to 8.00 GPa at an indentation depth of 1000 nm which indicates that.

[0016] As used herein, a "light sensor" is generally a device designed to generate at least one sensor signal in a manner that depends on the irradiation of a sensor region by a light beam. The sensor signal may generally be any signal indicative of at least one of transmission, absorption, emission, and reflection of the incident light beam irradiating the sensor region, and the incident light beam may be provided by an object. As an example, the sensor signal may be or include a digital signal and / or an analog signal. As an example, the sensor signal may be or include a voltage signal and / or a current signal. Additionally or alternatively, the sensor signal may be or include digital data. The sensor signal may include a single signal value and / or a series of signal values. The sensor signal may further include any signal derived by combining two or more individual signals, such as, for example, by averaging two or more signals and / or forming a quotient of two or more signals.

[0017] An "object" may generally be any object selected from living and non-living things. Thus, as an example, at least one object may include one or more articles and / or one or more parts of an article. Additionally or alternatively, the object may be or include one or more living things and / or one or more parts thereof, such as, for example, a human, such as a user, and / or one or more body parts of an animal.

[0018] As used herein, "position" generally refers to any information item regarding the position and / or orientation of an object in space. For this purpose, as an example, one or more coordinate systems may be used, and the position of the object may be determined using one, two, or three or more coordinates. In the present specification, the first coordinate refers to the depth of the object that indicates the distance between the optical sensor and the object, while the other two coordinates that may be perpendicular to the first coordinate can refer to the width of the object. As an example, one or more Cartesian coordinate systems and / or other types of coordinate systems may be used. As an example, the coordinate system may be the coordinate system of a detector having a predetermined position and / or orientation.

[0019] According to the present invention, the optical sensor includes at least one layer of a photoconductive material, and the layer of the photoconductive material can function as a sensor region. As used herein, "sensor region" is considered to be a compartment of the optical sensor designed to receive irradiation of the optical sensor by a light beam, and the irradiation causes the generation of at least one sensor signal in such a manner that it is received by the sensor region, and the generation of the sensor signal can be governed by a defined relationship between the sensor signal and the mode of irradiation of the sensor region. According to the present invention, the sensor region is formed by a photoconductive layer or a compartment thereof. Here, the sensor region may be formed as a single sensor region. In a particular embodiment, the photoconductive layer can include at least two individual sensor regions, preferably an array of individual sensor regions, and the sensor regions are applied directly or indirectly to the same substrate, also referred to as a "common substrate", and the same substrate can thus exhibit a fairly large area.

[0020] As used herein, the term "photoconductive material" refers to a material that can sustain an electric current and thus exhibits a specific electrical conductivity, which is particularly dependent on the irradiation of the material. Since the electrical resistivity is defined as the reciprocal value of the electrical conductivity, alternatively, the term "photoresistive material" can also be used to denote the same type of material. In this type of material, an electric current is conducted through the material via at least one first electrical contact to at least one second electrical contact, the first electrical contact being insulated from the second electrical contact, while both the first electrical contact and the second electrical contact are directly connected to the material. For this purpose, the direct connection can be provided by any known means known from the state of the art, such as plating, welding, soldering, wire bonding, ultrasonic thermocompression bonding, stitch bonding, ball bonding, wedge bonding, compliant bonding, thermocompression bonding, anodic bonding, direct bonding, plasma-activated bonding, eutectic bonding, glass frit bonding, adhesive bonding, transient liquid phase diffusion bonding, surface-activated bonding, tape automated bonding, or by depositing a metal, in particular gold, beryllium-doped gold, copper, aluminum, silver, platinum, or palladium, and an alloy containing at least one of the above metals in the contact area.

[0021] For the purposes of the present invention, the photoconductive material used in the sensor region of the optical sensor can preferably comprise an inorganic photoconductive material, and / or a solid solution thereof, and / or a doped variant thereof. As used herein, the term "solid solution" refers to a state of a photoconductive material in which at least one solute is contained in a solvent, thereby forming a homogeneous phase, where the crystal structure of the solvent can generally remain unchanged by the presence of the solute. As an example, a two-component lead selenide (PbSe) can be dissolved in lead sulfide (PbS) to reach 1-x Se x where the value of x can vary in the range from 0 to 1. As further used herein, the term "doped variant" can refer to a state of a photoconductive material in which a single atom away from the components of the material itself is introduced into a site within the crystal that is occupied by a native atom in the undoped state.

[0022] In this regard, the inorganic photoconductive material is, in particular, selenium, tellurium, selenium-tellurium alloy, metal oxide, group 4 element or compound, i.e., an element belonging to group 4 or a compound having at least one group 4 element, group 3-group 5 compound, i.e., a compound having at least one group 3 element and at least one group 5 element, group 2-group 6 compound, i.e., on the one hand, having at least one group 2 element or at least one group 12 element and, on the other hand, having at least one group 6 element, and / or a chalcogenide, preferably a chalcogenide selected from the group consisting of sulfide chalcogenide, selenide chalcogenide, ternary chalcogenide, quaternary chalcogenide and more than quaternary chalcogenide, or includes one or more of them. As commonly used, the term "chalcogenide" refers to a compound that may include elements of group 16 of the periodic table other than oxides, i.e., sulfides, selenides, and tellurides. Further, the term "chalcogenide" may also refer to mixed chalcogenides such as sulfoselenide.

[0023] In a particularly preferred embodiment of the present invention, the photoconductive material used in the photosensor may be selected from lead chalcogenides, preferably lead sulfide (PbS), its solid solution, and / or its doped variants. Particularly preferred photoconductive materials are generally known to exhibit characteristic absorption characteristics within the infrared spectral range. Therefore, a photosensor having a layer containing the aforementioned preferred photoconductive materials can preferably be used as an infrared sensor. However, other embodiments and / or other photoconductive materials are also feasible, such as those disclosed in, for example, WO2018 / 019921A1 and European Patent Application 19152511.2 filed on January 18, 2019.

[0024] Regarding a photoconductive material, a layer of a material that may include at least several crystals having a size exceeding 15 nm can be included. Here, the layer of the photoconductive material can be manufactured by applying at least one vapor deposition method selected from the group consisting of vacuum evaporation, sputtering, atomic layer deposition, chemical vapor deposition, spray pyrolysis, electrodeposition, anodization, electroconversion, electroless immersion growth, sequential ion adsorption and reaction, chemical bath deposition, and solution-gas interface technology. As a result, the layer of the photoconductive material can exhibit a thickness of 10 nm to 100 μm, preferably 100 nm to 10 μm, more preferably 300 nm to 5 μm. However, the above-mentioned and / or other photoconductive materials described later are also possible for this purpose and may be processed in the same or similar ways.

[0025] Preferably, the photoconductive material can be manufactured by depositing each material on an insulating substrate, preferably on a substrate as described in more detail later, particularly to impart mechanical stability to the layer of the photoconductive material. In this way, by depositing a selected layer on a suitable substrate and providing at least two individual electrical contacts, a photosensor according to the present invention can be obtained. Here, the irradiation of the photoconductive material in the sensor region by an incident light beam results in a change in the electrical conductivity in the irradiated layer of the photoconductive material.

[0026] As described above, the layer of the photoconductive material can be applied to at least one substrate. As commonly used, the term "substrate" refers to an extended body that supports a layer of material, particularly a layer of a photoconductive material as used herein, and is adapted to provide mechanical stability to the layer of the photoconductive material in particular. Thereby, the layer of the photoconductive material can be applied to the substrate indirectly or, preferably, directly. Here, the term "directly" refers to the direct attachment of the layer of the photoconductive material to the substrate, and the term "indirectly" refers to the attachment of the layer of the photoconductive material to the substrate via at least one intermediate layer such as an adhesive layer. Preferably, the substrate may be provided as a layer having a lateral extension that exceeds at least 5 times, preferably at least 25 times, more preferably at least 100 times the thickness of the layer. In particular, the thickness of the substrate may be 10 μm to 2000 μm, preferably 50 μm to 1000 μm, more preferably 100 μm to 500 μm.

[0027] Preferably, at least one of the substrate and the cover may be optically transparent within a selected wavelength range, particularly within the infrared spectral range or within the band as shown elsewhere in this specification. Therefore, it is particularly advantageous to select the material used for the cover layer to be optically transparent within the desired wavelength range, preferably by exhibiting particularly suitable absorption characteristics. Alternatively or additionally, the material applied to the substrate may exhibit optically transparent properties within the desired wavelength range. In particular, this feature can enable a wider range of material selection for the cover material that may not be optically transparent within the desired wavelength range because the substrate can exhibit sufficient transparency. For this purpose, the substrate can particularly include at least one insulating material that is at least partially transparent, and the insulating material may preferably be selected from at least one of glass, quartz, fused silica, metal oxides, or ceramic materials, preferably sapphire (Al2O3), and glass or quartz is particularly preferred.

[0028] In a particularly preferred embodiment, the substrate can be applied directly or indirectly to a circuit carrier device, such as a printed circuit board (PCB). As used herein, the term "printed circuit board" is usually abbreviated as "PCB" and refers to an electrically non-conductive planar board onto which at least one layer of conductive material, particularly a copper layer, is applied, specifically laminated onto the board. Other terms referring to this type of circuit carrier that further includes one or more electronic, electrical, and / or optical elements are printed circuit assembly, abbreviated as "PCA", printed circuit board assembly, abbreviated as "PCB assembly" or "PCBA", circuit card assembly or abbreviated as "CCA" or simply "card". In a PCB, the board can include glass epoxy, where cotton paper (typically tan or brown) impregnated with a phenolic resin can also be used as a board material. Depending on the number of sheets, the printed circuit board can be a single-sided PCB, a two-layer or double-sided PCB, or a multi-layer PCB, where different sheets are connected to each other by using so-called "vias". For the purposes of the present invention, the application of a single-sided PCB may be sufficient; however, other types of printed circuit boards may also be applicable. A double-sided PCB can have metal on both sides, while a multi-layer PCB can be designed by sandwiching additional metal layers between further layers of insulating material. In a multi-layer PCB, the layers can be laminated alternately, each metal layer is etched individually, and the internal vias can be plated before the multiple layers are laminated together. Further, the vias may be or may include copper-plated holes that are preferably designed as conductive paths through the insulating board.

[0029] The layer of the photoconductive material, the corresponding electrical contacts, and the substrate carrying further layers where applicable are specifically arranged on a circuit carrier device such as a PCB by means of adhesion, soldering, welding, or other methods, or can be deposited directly or indirectly on the adjacent surface of the circuit carrier device. For example, the substrate may be attached to a circuit carrier device such as a PCB by a thin film of adhesive arranged between the substrate and the adjacent surface of the circuit carrier device such as a PCB. For further embodiments of printed circuit boards, see https: / / en.wikipedia.org / wiki / Printed_circuit_board. However, alternatively, other types of circuit carriers can also be applied.

[0030] Furthermore, the optical sensor according to the invention comprises a cover covering the accessible surface of the photoconductive material and preferably also the accessible surface of the substrate. As commonly used, the term "accessible surface" refers to a part of the body reachable by the atmosphere surrounding the optical sensor, in particular a part of the layer of the photoconductive material or, where applicable, a part of the layer of the substrate. Preferably, the cover may be applied in such a way that it can be in direct contact with the upper and side surfaces of the layer of the photoconductive material and at least the side surfaces of the substrate. As already shown above, the substrate carries the layer of the photoconductive material, and thus the upper surface of the layer of the photoconductive material refers to the extensive surface of the layer of the photoconductive material that is not applied directly or indirectly to the substrate. As commonly used, the term "layer" refers to an extended body having two extensive surfaces with side surfaces arranged between those extensive surfaces. Since both the photoconductive material and the substrate are provided as layers, each includes side surfaces.

[0031] In a preferred embodiment, the cover may completely cover the accessible surfaces of both the layer of the photoconductive material and the side surface of the substrate, where in a particularly preferred arrangement the substrate, like a PCB, may be attached to the circuit carrier device in the manner described above. In this preferred embodiment, the cover may be a continuous coating that continuously covers both the layer of the photoconductive material and the side surface of the substrate. As a result, the cover can cover all the accessible surfaces of both the photoconductive material and the substrate, thus preventing direct contact between the material of the photoconductive layer or the substrate and the surrounding atmosphere, and thereby avoiding degradation of the photoconductive material due to external influences such as humidity and / or oxygen. However, as disclosed in WO2018 / 019921A1, a cover deposited only on the layer of the photoconductive material may already improve the long-term stability of the optical sensor. As a result, the cover contributes to reducing or eliminating external influences by minimizing or reducing the effects of humidity and / or oxygen on the layer of the photoconductive material. Furthermore, a cover that also covers the accessible surface of the substrate can improve such effects by blocking and / or interfering with the paths through which humidity and / or oxygen can be transmitted to the layer of the photoconductive material through or along the surface of the substrate.

[0032] Thus, the cover can be adapted to provide an improved encapsulation for the photoconductive material. As used herein, the term "encapsulation" particularly refers to a package, preferably an airtight package, for avoiding, as much as possible, partial or complete degradation of an optical sensor or a section thereof, particularly a section of the photoconductive material within the sensor region of the optical sensor, due to external influences such as humidity and / or oxygen contained in the surrounding atmosphere. Here, the package can preferably be adapted to cover all the accessible surfaces of the photoconductive material, where it may be considered that the layer of the photoconductive material can be deposited on a substrate that is already adapted to protect a section of the surface of the photoconductive material. In other words, the substrate and the cover layer can be adapted to cooperate to complete an improved packaging, preferably an improved airtight packaging, of the photoconductive material.

[0033] Preferably, at least one deposition method can be used to deposit the cover. For this purpose, the at least one deposition method may in particular be selected from atomic layer deposition, chemical vapor deposition, sputtering processes, or combinations thereof. As a result, the cover is, in a particularly preferred embodiment, an atomic deposition coating, a chemical vapor deposition coating, a sputter coating, or a coating produced by using at least two of the above deposition methods, or may contain them, and a coating produced by using an atomic deposition coating or a combination of an atomic deposition coating and sputtering is particularly preferred. In other words, the cover can be obtained by an ALD process, a CVD process, a sputtering process, or a combination thereof in this particularly preferred embodiment, and an ALD process or a combination of ALD and sputtering is particularly preferred. In particular, the cover can contain at least one metal-containing compound, and the at least one metal may be selected from the group consisting of Al, Ti, Ta, Mn, Mo, Zr, Hf, and W. Furthermore, the at least one metal-containing compound may preferably be selected from the group consisting of oxides, hydroxides, or combinations thereof. Therefore, the metal-containing compound may preferably contain at least one oxide, at least one hydroxide, or a combination thereof, preferably at least one oxide, at least one hydroxide, or a combination thereof of Al, Ti, Zr, or Hf. In a particularly preferred embodiment of the present invention, the metal-containing compound contained by the cover may be a composition containing aluminum oxide and / or aluminum hydroxide, and this composition is also called Al2O3 for simplicity as commonly used. Furthermore, the cover can have a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm. This thickness can in particular reflect the amount of the metal-containing compound in the cover, which can be advantageous for achieving the above function of providing encapsulation of the photoconductive material.

[0034] In an even more particularly preferred embodiment of the present invention, the cover can be conformal with respect to the adjacent surface of the photoconductive material or substrate. As defined above, the thickness of the conformal cover can thus follow the corresponding surface of the photoconductive material or substrate within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm, the deviation occurring at at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the cover, thereby excluding any contamination or imperfection that may be present on the cover surface.

[0035] In a particularly preferred embodiment, the cover may partially or completely cover an electrical contact that can be specifically configured to be joinable, such as to one or more leads to an external circuit. Here, the electrical contact may be connectable by using a wire such as a gold or aluminum wire, where the electrical contact may preferably be connectable through the cover. In certain embodiments, an adhesive layer may be provided on the electrical contact, in which case the adhesive layer may be specifically adapted for the connection. For this purpose, the adhesive layer may comprise at least one of Ni, Cr, Ti, or Pd.

[0036] According to the present invention, a substrate, a layer of a photoconductive material, and a cover are arranged in the form of a stack, where an electrical contact that contacts the layer of the photoconductive material is spatially separated from the stack. As is commonly used, the term "stack" refers to a configuration that includes at least two individual layers, where one of the individual layers is arranged on top of another individual layer in a specific direction. For the stack described herein, a normal vector that can be perpendicular to a certain extent of the surface of at least one individual layer can be used as the specific direction according to which the stack is arranged. Thus, the substrate may be considered as a base layer on which a layer of the photoconductive material is arranged, and the cover is further arranged on the layer of the photoconductive material. Such a consideration can be further justified by the method of manufacturing the stack, which will be described in more detail below, specifically, by providing the substrate as the base layer and subsequently depositing further layers, that is, first depositing the layer of the photoconductive material and then depositing the cover. After manufacturing, the stack can be rotated in any direction as a whole, but the rotation may be such that it does not affect the arrangement and configuration of the stack. In this regard, the coating of the side surface of the layer of the photoconductive material and, where applicable, the side surface of the substrate by the cover, as described in more detail elsewhere in this specification, can be excluded from the consideration.

[0037] Furthermore, according to the present invention, the stack included in the optical sensor as described above exhibits particularly selected static mechanical properties. As used herein, the term "mechanical properties" of a body such as a stack refers to the response of the body to an incident input applied to the body (also indicated by the term "sensitivity"). Here, the static mechanical properties, which refer to the responsiveness or sensitivity of the body to an incident static force applied to the body, are accessible by performing quasi-static nanoindentation measurements on the body. As commonly used, "quasi-static nanoindentation measurements" relate to the measurement of Young's modulus, indicated by either the term "elastic modulus" or "elastic coefficient", and the measurement of the hardness of the body, which are preferably performed in accordance with standards EN ISO 14577-1:2015 and EN ISO 14577-4:2016. More generally, as used, the term "nanoindenter" refers to a probe having a tip (chip) designed to penetrate into a very small volume of a sample containing a stack for performing quasi-static nanoindentation measurements. For this purpose, the tip of the nanoindenter preferably has a pyramid shape, and a "Berkovich tip" compliant with the EN ISO 14577-2:2015 standard is particularly preferred. For details regarding quasi-static nanoindentation measurements, related probes, and the results obtained, reference can be made to the standards described herein.

[0038] Therefore, the Young's modulus of the body refers to the tensile elastic modulus of the body regarding the tendency of the body to deform along an axis when a force is applied along that axis. Specifically, the Young's modulus is defined as the ratio of tensile stress to tensile strain. The tensile stress is measured in GPa and is related to the ratio of the force that induces deformation of the body to the area to which the force is applied. The tensile strain is the dimensionless ratio of the deformation of the body to the reference dimension of the body. Here, the change in the dimension of the body can include the movement of the body including translation and / or rotation of the body, and / or the change in the shape of the body, and thus the change in the size or volume of the body. According to the present invention, the Young's modulus is measured by using the above-described nanoindenter. Furthermore, the hardness of the body refers to the resistance of the body to local deformation of the body induced by a certain compressive load applied to the body, and thus can also be measured by applying a nanoindenter. As a result, the Young's modulus and hardness can be considered as reliable indicators for determining the static mechanical properties of the stack included in the optical sensor.

[0039] Surprisingly, the optical sensor has the following characteristics in the quasi-static nanoindentation measurement of the stack, the Young's modulus is, at a penetration depth of 100 nm, it is 75 GPa to 107 GPa, preferably 80 GPa to 102 GPa, more preferably 86 GPa to 96 GPa, at a penetration depth of 300 nm, it is 47 GPa to 127 GPa, preferably 60 GPa to 114 GPa, more preferably 74 GPa to 100 GPa, at a penetration depth of 1000 nm, it is 49 GPa to 119 GPa, preferably 61 GPa to 107 GPa, more preferably 72 GPa to 96 GPa, On the other hand, the hardness is, at a penetration depth of 100 nm, it is 1.20 GPa to 4.70 GPa, preferably 1.78 GPa to 4.12 GPa, more preferably 2.37 GPa to 3.53 GPa, at a penetration depth of 300 nm, it is 1.60 GPa to 4.60 GPa, preferably 2.10 GPa to 4.10 GPa, more preferably 2.60 GPa to 3.60 GPa, At a penetration depth of 1000 nm, it is 1.60 GPa to 8.00 GPa, preferably 2.67 GPa to 6.93 GPa, more preferably 3.73 GPa to 5.87 GPa. In the case, as shown in more detail below, it has been found to exhibit favorable characteristics.

[0040] Although not wishing to be bound by theory, the above characteristics preferably provide an appropriate description of selected parameters that are preferably balanced when manufacturing a long-term stable sensor having the desired high quality. In particular, the photoconductivity of a photoconductive sensor can preferably depend strongly on the crystallinity of the bulk material selected from the crystal structure, crystal size, bulk-to-surface ratio, and crystal defects. Further, an activation layer that provides surface defects that result in excellent detectability, and a cover layer that acts as one or both of a seal to form and / or preserve a given state of the defects, strongly depend on the nature of its amorphous state, particularly the amorphous state with a very low degree of crystallinity. When the size of the photoconductive crystal is small, or the aggregation and / or bonding between crystals is weak, both the hardness and Young's modulus become small. When the crystallinity of the cover layer is high and / or the photoconductive crystallites are large, both the hardness and Young's modulus become large. Further, both the hardness and Young's modulus characterize the connectivity and bonding between the cover layer and the photoconductive crystal. Therefore, both the hardness and Young's modulus measured at different penetration depths are considered to be ideal indicators for characterizing the complex interplay of the microscopic chemical parameters and their relationship to the detectability and long-term stability of these optical sensors.

[0041] In particular, the overall long-term quality of the optical sensor can thus be determined by measuring the sensor parameters thousands of hours after manufacture. To obtain the selection criteria for the high-quality and long-term stable sensors according to the present invention, the optical sensor is measured 4000 ± 50 hours after manufacture, and the relative dark resistance change with respect to the dark resistance immediately after manufacture, the relative detectivity change with respect to the detectivity immediately after manufacture, and the absolute maximum deviation from the linear resistivity between -10V and +10V are determined. As a result, the selection criteria are defined as optical sensors with a relative dark resistance change of less than 0.1%, a relative detectivity change of less than 0.1%, and an absolute maximum deviation from the linear resistivity between -10V and +10V of the dark resistance of less than 0.1%. For each optical sensor that meets the indicated selection criteria, only one of the following parameters: Young's modulus at penetration depths of 100 nm, 300 nm, 1000 nm, or hardness at penetration depths of 100 nm, 300 nm, 1000 nm was determined in a quasi-static nanoindentation measurement of the stack. Each measurement was performed on 30 individual optical sensors. From the measurement sets of each parameter, the mean value μ and the standard deviation σ were obtained. As a result, an optical sensor showing a parameter within the 1.5σ interval (μ ± 1.5σ) centered on the mean value is regarded as the optical sensor according to the present invention. An optical sensor showing a parameter within the σ interval (μ ± σ) centered on the mean value is a preferred optical sensor. An optical sensor showing a parameter within the 0.5σ interval (μ ± 0.5σ) centered on the mean value is particularly preferred.

[0042] In a particularly preferred embodiment of the present invention, the stack included in the above optical sensor can further exhibit particularly selected dielectric properties. Thus, the dielectric properties, which refer to dielectric parameters such as the dielectric loss of the body with respect to the incident electromagnetic wave applied to the body, are accessible by a microwave reflection measurement experiment that can be carried out at a microwave frequency of 75 GHz, and the "reflectivity coefficient" indicated by the term "S11" is measured. As is generally used, the "S11 reflectivity coefficient" is defined as 10 log(P refl / P in ), where P in represents the output of the microwave incident on the sample including the stack, and P reflshows the output of the reflected microwave reflected by the sample. As a result, the S11 reflectivity coefficient can be considered a reliable indicator for determining the dielectric properties of the stack included in the optical sensor.

[0043] Surprisingly, the optical sensor further found that when the stack has the following characteristics, that is, in the 75 GHz microwave reflection measurement experiment of the stack, the reflectivity coefficient S11 is -6.70 dB to -1.30 dB, preferably -5.80 dB to -2.20 dB, more preferably -4.90 dB to -3.10 dB, it can exhibit preferable characteristics as shown in more detail below.

[0044] While not wishing to be bound by theory, the above characteristics preferably provide a further appropriate description of the selected parameters that are preferably balanced when manufacturing a long-term stable sensor with the desired high quality. In particular, microwave reflection measurements can be used to provide insights into the dielectric parameters of conductive materials and the effective mobility of defect-based charges. Further, microwave reflection measurements can be used to detect leaks in the enclosure. Further, microwave reflection measurements can also be used for moisture measurement. The photoconductive sensor is very sensitive to moisture because moisture changes the photoconductive properties, particularly those selected from charge mobility, resistivity, and detectivity. Further, charge mobility, resistivity, detectivity and / or dielectric loss particularly depend on the surface defects of the photoconductive crystal including chemical bonds to the cover layer. Therefore, microwave reflection measurements can constitute the measurement of a preferred combination of microscopic charge mobility, resistivity, detectivity, defect structure, and moisture content, which can make it possible to monitor the balance of complex and difficult-to-measure parameters, and the balance of these parameters can be considered preferable for obtaining a high-performance sensor.

[0045] In particular, the overall long-term quality of the photoconductive sensor can thus be determined by measuring the sensor parameters several thousand hours after manufacture. For each optical sensor that meets the indicated selection criteria as defined above, the reflectivity coefficient S11 of the stack was determined in a microwave reflection measurement experiment at 75 GHz. Each measurement was performed on 30 individual optical sensors. For each set of measurements, an average value μ and a standard deviation σ were obtained for the reflectivity factor S11. As described above, an optical sensor showing parameters within a 1.5σ interval (μ ± 1.5σ) centered on the average value is considered an optical sensor according to the present invention. An optical sensor showing parameters within a σ interval (μ ± σ) centered on the average value is a preferred optical sensor. An optical sensor showing parameters within a 0.5σ interval (μ ± 0.5σ) centered on the average value is particularly preferred.

[0046] In a particularly preferred embodiment, the stack included in the above optical sensor can further exhibit a particularly selected composition. As used herein, the term "composition" of the stack refers to the distribution of the components within the stack. In this particularly preferred embodiment, wavelength dispersive X-ray spectroscopy (WDXS) of the stack may be employed to determine the characteristics of the stack composition. As commonly used, the term "wavelength dispersive X-ray spectroscopy" or "WDXS" refers to a specific method for determining the chemical composition and composition of phases on a microscale with high sensitivity and high resolution. For this purpose, an electron beam is irradiated onto a sample containing the stack, and the X-rays emitted by the sample are subsequently collimated to irradiate a known single crystal at an exact angle, and the single crystal diffracts photons for collection by a detector. Here, the single crystal, the sample, and the detector are accurately mounted on a goniometer, and the distance between the sample and the single crystal may be equal to the distance between the single crystal and the detector. In a preferred embodiment, an automatic exchange unit can be employed to change the single crystal according to the incident energy in particular, thereby enabling the analysis of different components. As a result, wavelength dispersive X-ray spectroscopy counts only X-rays of a single wavelength at a time.

[0047] In particular, the photoconductive material that can be used in the optical sensor according to the present invention may specifically be a lead chalcogenide, a solid solution, and / or a doped modification thereof. At the same time, the cover may be an amorphous cover containing an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof, which is herein shown as "Al2O3" for simplicity. Thus, using wavelength-dispersive X-ray spectroscopy makes it possible to determine the composition of a stack including an Al2O3 cover covering a PbS layer deposited on a glass substrate. Here, wavelength-dispersive X-ray spectrometric measurements are performed using an electron beam microanalyzer as a detector and using thallium phthalate (TAP) or pentaerythritol H-type (PET H) as a single crystal for WDXS, and the WDXS measurements may preferably be performed using an acceleration voltage of 20 kV. As a result, the net count of the WDXS measurement is the peak maximum of each Al K α1 line, Pb M α1 line, and S K α1 line peak maximum value.

[0048] Surprisingly, in the wavelength-dispersive X-ray spectroscopy of the stack using an electron beam microanalyzer and an acceleration voltage of 20 kV, the optical sensor shows favorable characteristics when the ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the net count / s·nA measured at the peak maximum of the Pb M α1 line is 0.113 to 0.279, preferably 0.141 to 0.251, and more preferably 0.168 to 0.224.

[0049] In a further particularly preferred embodiment where lead sulfide (PbS) is selected as the lead chalcogenide of the photoconductive material used in the optical sensor, in the wavelength-dispersive X-ray spectroscopy of the stack using an electron beam microanalyzer and an acceleration voltage of 20 kV, the optical sensor has the net count / s·nA measured at the peak maximum of the Al K α1 line, and the Pb M α1 line and S K α1It has further been found that favorable characteristics can be exhibited when the further ratio to the total net count / s·nA measured by the line is 0.0841 to 0.1456, preferably 0.0944 to 0.1354, and more preferably 0.1046 to 0.1251.

[0050] Although not wishing to be bound by theory, the above dielectric properties preferably provide a further appropriate description of the selected parameters that are preferably balanced when manufacturing a long-term stable sensor having the desired high quality. In particular, the properties of the photoconductive sensor strongly depend on the photoconductive crystal and their interaction with the cover layer. The cover layer may be a conformal layer and thus may follow the surface shape of the photoconductive crystal. The distribution of chemical elements can thus vary along the normal to the surface. Here, near the substrate, the element distribution becomes essentially the same as that of the photoconductive material, while near the surface, it becomes essentially the same as that of the cover layer, and in between, the element distribution can strongly depend on the shape, size and / or degree of aggregation of the photoconductive crystal, as well as the volume between the crystals. For this purpose, WDX spectroscopy can be used for known measurements of the element distribution not only on the surface but also below the surface. WDX spectroscopy can thus be used to gain insight into the complex parameters of the composition of the crystal and the cover layer.

[0051] In particular, the overall long-term quality of the photoconductive sensor can thus be determined by measuring the sensor parameters thousands of hours after manufacture. For each optical sensor that meets the selection criteria defined above, the following parameters: in wavelength-dispersive X-ray spectroscopy of the stack using an electron beam microanalyzer and an acceleration voltage of 20 kV, in the case of a sensor containing Al in the cover layer and Pb in the photoconductive layer, the net count / s·nA measured at the peak maximum of the Al K α1 line and the ratio to the net count / s·nA measured at the peak maximum of the Pb M α1 line, or, in the case of a sensor containing Al, Pb and S in the photoconductive layer in the cover layer, Al K α1Net counts / s·nA measured at the peak maximum of the line, and Pb M α1 line and S K α1 Only one of the ratios to the sum of the net counts / s·nA measured with the line was determined. Each measurement was made with 30 individual optical sensors. For each measurement set, an average value μ and a standard deviation σ were obtained for the reflectance factor S11. As described above, an optical sensor showing a parameter within the 1.5σ interval (μ ± 1.5σ) centered on the average value is regarded as an optical sensor according to the present invention. An optical sensor showing a parameter within the σ interval (μ ± σ) centered on the average value is a preferred optical sensor. An optical sensor showing a parameter within the 0.5σ interval (μ ± 0.5σ) centered on the average value is particularly preferred.

[0052] For further details regarding the optical sensor or any of its components, specifically the substrate, the photoconductive material, the cover, or the electrical contacts, reference is made to WO2018 / 019921A1 and European patent application 19152511.2 filed on January 18, 2019.

[0053] In a further aspect of the present invention, a method of selecting an optical sensor having overall long-term quality is disclosed. Here, the method comprises the following steps: · Providing an optical sensor with a stack, said stack comprising: a substrate, at least one layer of a photoconductive material applied on said substrate, a cover covering the accessible surface of the layer of the photoconductive material, at least two individual electrical contacts spatially separated from said stack and in contact with the layer of the photoconductive material; · Measuring the Young's modulus and hardness of the stack in a quasi-static nanoindentation measurement; · Selecting an optical sensor showing preferred static mechanical properties in a quasi-static nanoindentation measurement of the stack, where the Young's modulus is 75 GPa to 107 GPa at an indentation depth of 100 nm, The penetration depth is 300 nm and the pressure is 47 GPa to 127 GPa, The penetration depth is 1000 nm and the pressure is 49 GPa to 119 GPa, The hardness is The penetration depth is 100 nm and the hardness is 1.20 GPa to 4.70 GPa, The penetration depth is 300 nm and the hardness is 1.60 GPa to 4.60 GPa, The penetration depth is 1000 nm and the hardness is 1.60 GPa to 8.00 GPa, The penetration depth is determined with respect to the surface of the stack, and the method includes selecting an optical sensor, or, if the Young's modulus and hardness of the stack deviate from the preferred static mechanical properties of the stack, rejecting the optical sensor.

[0054] For further details regarding the method of selecting an optical sensor with overall long-term quality, reference can be made to the description of the optical sensor in this specification.

[0055] In a further aspect of the invention, a detector for optical detection, in particular for the detection of optical radiation in the infrared spectral range, in particular a detector for sensing at least one of transmission, absorption, emission and reflection provided by at least one light beam, or a detector for determining the position of at least one object, in particular for determining the position of at least one object with respect to the depth or both the depth and width of at least one object, is disclosed. According to the invention, the detector for optical detection of at least one object is at least one optical sensor described in other parts of this specification, wherein the optical sensor includes at least one sensor region, and the optical sensor is designed to generate at least one sensor signal in a manner dependent on the irradiation of the sensor region by a light beam; and at least one evaluation device, wherein the evaluation device is designed to generate at least one information item regarding the optical radiation provided by the light beam by evaluating the sensor signal of the optical sensor. including.

[0056] In this specification, the components listed may be separate components. Alternatively, two or more components may be integrated into one component. Furthermore, at least one evaluation device may preferably be formed as a separate evaluation device independent of a transfer device that may be selected from at least one of an optical lens, a mirror, a beam splitter, an optical filter, and an optical sensor. However, preferably, it may be connected to an optical sensor to receive a sensor signal. Alternatively, at least one evaluation device may be completely or partially integrated into the optical sensor.

[0057] According to the present invention, the detector includes at least one of the optical sensors as described in other parts of this document. Therefore, the detector may preferably be designed to detect electromagnetic radiation in a rather wide spectral range, where the infrared (IR) spectral range may be particularly preferred. Here, due to the photoconductive layer in the sensor region of the optical sensor, indium gallium arsenide (InGaAs) at wavelengths up to 2.6 μm, indium arsenide (InAs) at wavelengths up to 3.1 μm, lead sulfide (PbS) at wavelengths up to 3.5 μm, lead selenide (PbSe) at wavelengths up to 5 μm, indium antimonide (InSb) at wavelengths up to 5.5 μm, and mercury cadmium telluride (MCT, HgCdTe) at wavelengths up to 16 μm can be particularly selected, where lead sulfide (PbS), solid solutions and / or their doped variants may be particularly preferred.

[0058] As a result, when the light beam impinges on the sensor area, at least two electrical contacts can provide a sensor signal that depends on the electrical conductivity of the photoconductive material. The term "light beam" generally refers to the amount of light emitted in a specific direction. Thus, the light beam can be a bundle of light rays having a predetermined spread in a direction perpendicular to the propagation direction of the light beam. Preferably, the light beam may be or include one or more Gaussian light beams, which may be characterized by one or more Gaussian beam parameters such as the beam waist, Rayleigh length, or any other beam parameter, or a combination of beam parameters suitable for characterizing the spread of the beam diameter and / or the propagation of the beam in space. Here, the light beam can be emitted by the object itself, i.e., can originate from the object. Additionally or alternatively, another source of the light beam is also feasible. Thus, as will be outlined in more detail below, one or more irradiation sources may be provided, which irradiate the object using one or more primary light rays or beams, such as one or more primary light rays or beams having predetermined characteristics. In the latter case, the light beam propagating from the object to the detector may be a light beam reflected by the object and / or a reflecting device connected to the object.

[0059] As used herein, the term "evaluation device" generally refers to any device designed to generate at least one information item, i.e., related to at least one of transmission, absorption, emission, and reflection, or related to at least one object, or to determine the position of at least one object, particularly the depth or both the depth and width of the at least one object, of at least one information item. As an example, the evaluation device can be or include one or more integrated circuits such as one or more application-specific integrated circuits (ASICs), and / or one or more digital signal processors (DSPs), and / or one or more field-programmable gate arrays (FPGAs), and / or one or more computers, preferably one or more microcomputers and / or microcontrollers, etc., as one or more data processing devices. Additional components can be constituted by, for example, one or more preprocessing devices such as one or more devices for receiving and / or preprocessing sensor signals such as one or more analog-to-digital converters and / or one or more filters, and / or data acquisition devices, etc. As used herein, the sensor signal can generally refer to one of the vertical sensor signals and, if applicable, the lateral sensor signal. Further, the evaluation device can include one or more data storage devices. Further, as outlined above, the evaluation device can include one or more interfaces such as one or more wireless interfaces and / or one or more wired interfaces.

[0060] For further information on detectors or any of their components for optical detection, particularly with respect to the evaluation device, reference can be made to WO2014 / 097181A1 and WO2018 / 019921A1.

[0061] In a further aspect of the present invention, a method of manufacturing an optical sensor is disclosed. The method may preferably be used for producing or manufacturing at least one optical sensor according to the present invention, such as at least one optical sensor according to one or more embodiments disclosed in further detail below in other parts of this document. Accordingly, for any embodiment of the method, reference may be made to the description of the various embodiments of the optical sensor.

[0062] The method includes the following steps which can be performed in a given order or in a different order. Further, additional method steps not described may be provided. Unless otherwise specified, two or more, or even all, of the method steps may be performed at least partially simultaneously. Further, two or more, or even all, of the method steps may be repeatedly performed two or more times.

[0063] The method according to the present invention comprises the following steps: a) providing a substrate, at least one layer of a photoconductive material applied to the substrate, and at least two individual electrical contacts in contact with the layer of the photoconductive material; b) then depositing an amorphous cover on an accessible surface of the layer of the photoconductive material, whereby a stack comprising the substrate, the at least one layer of the photoconductive material, and the cover is obtained; c) measuring the Young's modulus and the hardness of the stack in a quasi-static nanoindentation measurement; The method of manufacturing the optical sensor is such that the optical sensor has, in a quasi-static nanoindentation measurement of the stack according to step c), the Young's modulus is 75 GPa to 107 GPa at an indentation depth of 100 nm, 47 GPa to 127 GPa at an indentation depth of 300 nm, 49 GPa to 119 GPa at an indentation depth of 1000 nm, the hardness is 1.20 GPa to 4.70 GPa at an indentation depth of 100 nm, The penetration depth is 300 nm and the pressure is 1.60 GPa to 4.60 GPa, the penetration depth is 1000 nm and the pressure is 1.60 GPa to 8.00 GPa, which is carried out as shown.

[0064] According to step a), a substrate, at least one layer of a photoconductive material, and individual electrical contacts are provided. In particular, the materials for the substrate, the layer of photoconductive material, and the electrical contacts can each be selected from the corresponding lists of materials presented above.

[0065] According to step b), the cover can be produced using at least one of the methods described above. Here, step b) may be repeated at least once, preferably at least 10 times, more preferably at least 100 times. Preferably, at least one metal-containing compound and, where applicable, other types of compounds are deposited until a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 100 nm, most preferably 50 to 95 nm is achieved. Here, at least one metal-containing compound and, where applicable, other types of compounds are deposited such that the cover can preferably be conformal to the adjacent surface of the photoconductive material. Thus, the thickness of the conformal cover may follow the corresponding surface of the photoconductive material or the substrate within a deviation range of ±50 nm, preferably ±20 nm, most preferably ±10 nm over at least 90%, preferably at least 95%, most preferably at least 99% of the surface of the conformal cover.

[0066] In a particularly preferred embodiment of the present invention, at least one deposition method is used to deposit a metal-containing compound. Preferably, the deposition method can be selected from at least one of an atomic layer deposition (ALD) process, a chemical vapor deposition (CVD) process, a sputtering process, or a combination thereof. For further details regarding the ALD process or the CVD process, reference can be made to the above description. For the purpose of providing a metal-containing compound, two different types of precursors can preferably be used, where the first precursor is a metal-organic precursor or contains it, and the second precursor can be a fluid or contain it. As commonly used, the term "fluid" can refer to the non-solid state of the second precursor. As an example, to provide an aluminum (Al)-containing compound, the first precursor is TMA, i.e., trimethylaluminum Al(CH3)3 or contains it, while the second precursor can be H2O, oxygen, air, or their solutions or ozone or contain them. In the present specification, at least one precursor can be mixed with an inert gas, particularly nitrogen (N2) or argon (Ar), in order to provide a particularly stable fluid flow.

[0067] As described above, a desired optical sensor is generally designed to generate at least one sensor signal in response to irradiation of a sensor region included in the optical sensor by an incident light beam. For this purpose, at least two electrical contacts are further provided that are adapted to make electrical contact with a photoconductive material included within the sensor region. Generally, the electrical contacts can be provided either before or during any one of method steps a) or b). In a particularly preferred embodiment, the electrical contacts can be provided prior to step b) by providing a deposited metal layer, such as by known deposition techniques, where the metal layer can particularly include one or more of silver, aluminum, platinum, magnesium, chromium, titanium, gold, or graphene. Alternatively, the electrical contacts can be provided by a galvanic or chemical deposition process, such as electroless Ni, electroless Au, galvanic Ni, or galvanic Au. Here, the cover can be deposited in a manner that also completely or partially covers the electrical contacts. In this particular embodiment, the electrical contacts are preferably at least partially and preferably completely covered by the cover, and thus can be joined to at least one external connection by using a conductive lead wire, preferably in the form of a wire, particularly by using a wire of gold (Au), aluminum (Al), or copper (Cu), where the conductive lead wire can particularly be joined to the electrical contacts through the cover layer. By way of example, a gold (Au) contact covered by a cover layer can subsequently be connected by wire bonding.

[0068] According to step c), the Young's modulus and hardness of the stack are measured by quasi-static nanoindentation measurements as described above and in more detail below.

[0069] In a particularly preferred embodiment, the method is the following steps, as described above and in more detail below: d) determining a reflectivity coefficient S11 of the stack by applying a 75 GHz microwave reflection measurement experiment to the stack; may further be included.

[0070] Even more particularly preferred embodiments, wherein the photoconductive material is selected from the group consisting of lead chalcogenides, solid solutions and / or their doped variants, the lead chalcogenide being specifically lead sulfide (PbS), and the cover being an amorphous cover containing an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof. In an even more particularly preferred embodiment, the method comprises the following steps, as described above and in more detail below: e) performing wavelength dispersive X-ray spectroscopy (WDXS) of the stack using an electron beam microanalyzer with an acceleration voltage of 20 kV; may further be included.

[0071] As described above, the method for manufacturing the optical sensor of the present invention is carried out such that the stack included by the optical sensor exhibits desired static mechanical properties, preferably desired dynamic mechanical properties and / or desired composition.

[0072] In addition, details regarding the manufacturing process of the optical sensor are described in other parts of this document.

[0073] The device according to the present invention can be used in combination with surface mount technology packages such as bump chip carriers, ceramic leadless chip carriers, leadless chip carriers, lead chip carriers, lead ceramic chip carriers, dual leadless chip carriers, plastic lead chip carriers, package-on-package chip carriers, etc. Further, the device according to the present invention can be used in combination with semiconductor packages of standard through-hole or source mount technologies, such as DO-204, DO-213, metal electrode leadless surface, DO-214, SMA, SMB, SMC, GF1, SOD, SOT, TSOT, TO-3, TO-5, TO-8, TO-18, TO-39, TO-46, TO-66, TO-92, TO-99, TO-100, TO-126, TO-220, TO-226, TO-247, TO252, TO-263, TO-263, THIN, SIP, SIPP, DFN, DIP, DIL, Flat Pack, SO, SOIC, SOP, SSOP, TSOP, TSSOP, ZIP, LCC, PLCC, QFN, QFP, QUIP, QUIL, BGA, eWLB, LGA, PGA, COB, COF, COG, CSP, Flip Chip, PoP, QP, UICC, WL-CSP, WLP, MDIP, PDIP, SDIP, CCGA, CGA, CERPACK, CQGP, LLP, LGA, LTCC, MCM, MICRO SMDXT, etc. Further, the device according to the present invention can be used in combination with pin grid arrays (PGA) such as OPGA, FCPGA, PAC, PGA, CPGA, etc. Further, the device according to the present invention can be used in combination with flat packages such as CFP, CQFP, BQFP, DFN, ETQFP, PQFN, PQFP, LQFP, QFN, QFP, MQFP, HVQFP, SIDEBRAZE, TQFP, TQFN, VQFP, ODFN, etc. Further, the device according to the present invention can be used in combination with small outline packages such as SOP, CSOP MSOP, PSOP, PSON, PSON, QSOP, SOIC, SSOP, TSOP, TSSOP, TVSOP, μMAX, WSON, etc.Furthermore, the device according to the present invention can be used in combination with chip scale packages such as CSP, TCSP, TDSP, MICRO SMD, COB, COF, COG, etc. Furthermore, the device according to the present invention can be used in combination with ball grid arrays such as FBGA, LBGA, TEPBGA, CBGA, OBGA, TFBGA, PBGA, MAP-BGA, UCSP, μBGA, LFBGA, TBGA, SBGA, UFBGA, etc. Furthermore, the device according to the present invention can be combined with further electronic devices such as chip-in-multi-chip packages such as SiP, PoP, 3D-SiC, WSI, proximity communication, etc. For further information regarding integrated circuit packaging, the following sources can be referred to.

[0074] - https: / / en.wikipedia.org / wiki / List_of_integrated_circuit_packaging_types or, - https: / / en.wikipedia.org / wiki / List_of_integrated_circuit_package_dimensions

[0075] In a further aspect of the present invention, the use of the detector according to the present invention is disclosed. Among them, the purpose of the use of the detector is selected from the group consisting of gas detection applications, fire detection applications, flame detection applications, heat detection applications, smoke detection applications, combustion monitoring applications, spectroscopic applications, temperature sensing applications, motion sensing applications, industrial monitoring applications, chemical sensing applications, exhaust gas monitoring applications, and security applications. In particular, the detector can be used for infrared detection applications, heat detection applications, thermometer applications, heat pursuit applications, flame detection applications, fire detection applications, smoke detection applications, temperature sensing applications, spectroscopic applications, etc. Furthermore, the detector can be used for monitoring exhaust gases, monitoring combustion processes, monitoring industrial processes, monitoring chemical processes, monitoring food processing processes, etc. Furthermore, the detector may be used for temperature control, motion control, exhaust control, gas sensing, gas analysis, motion sensing, chemical sensing, etc. For further uses of the optical sensor and detector disclosed herein, reference can be made to WO2016 / 120392A1 and WO2018 / 019921A1. However, further application fields are still conceivable.

[0076] The above-mentioned optical sensor and detector, method, and proposed uses have considerable advantages compared to the prior art. Therefore, the optical sensor according to the present invention can be particularly advantageous because the high performance and stability of the optical sensor can be maintained over a long period of time. As a result, these advantages are advantageous for meeting the specific requirements for applications to safety-related devices such as gas sensors, spark sensors, or flame sensors, as well as for applications to the field of security technology.

[0077] In summary, in the context of the present invention, the following embodiments are considered preferable. Embodiment 1: An optical sensor comprising a stack, wherein the stack a substrate, at least one layer of a photoconductive material applied on the substrate, a cover covering the accessible surface of the layer of the photoconductive material, and at least two separate electrical contacts spatially separated from the stack and in contact with the layer of the photoconductive material. In the quasi-static nano-indentation measurement of the stack, the optical sensor has a Young's modulus of 75 GPa to 107 GPa at a penetration depth of 100 nm, 47 GPa to 127 GPa at a penetration depth of 300 nm, 49 GPa to 119 GPa at a penetration depth of 1000 nm, and a hardness of 1.20 GPa to 4.70 GPa at a penetration depth of 100 nm, 1.60 GPa to 4.60 GPa at a penetration depth of 300 nm, 1.60 GPa to 8.00 GPa at a penetration depth of 1000 nm, indicating that of the optical sensor.

[0078] Embodiment 2: In the quasi-static nano-indentation measurement of the stack, the optical sensor has a Young's modulus of 80 GPa to 102 GPa at a penetration depth of 100 nm, 60 GPa to 114 GPa at a penetration depth of 300 nm, 61 GPa to 107 GPa at a penetration depth of 1000 nm, and a hardness of 1.78 GPa to 4.12 GPa at a penetration depth of 100 nm, 2.10 GPa to 4.10 GPa at a penetration depth of 300 nm, 2.67 GPa to 6.93 GPa at a penetration depth of 1000 nm, indicating that of the optical sensor according to the preceding embodiment.

[0079] Embodiment 3: In the quasi-static nano-indentation measurement of the stack, the optical sensor has a Young's modulus of 86 GPa to 96 GPa at a penetration depth of 100 nm, 74 GPa to 100 GPa at a penetration depth of 300 nm, 72 GPa to 96 GPa at a penetration depth of 1000 nm, and a hardness of 2.37 GPa to 3.53 GPa at a penetration depth of 100 nm, At a penetration depth of 300 nm, it is 2.60 GPa to 3.60 GPa, and at a penetration depth of 1000 nm, it is 3.73 GPa to 5.87 GPa, A photosensor according to the preceding embodiment, which shows this.

[0080] Embodiment 4: The photosensor is a photosensor according to any one of the preceding embodiments, which shows that in the 75 GHz microwave reflection measurement experiment of the stack, the reflection coefficient S11 is -6.70 dB to -1.30 dB.

[0081] Embodiment 5: The photosensor is a photosensor according to the preceding embodiment, which shows that in the 75 GHz microwave reflectivity experiment of the stack, the reflection coefficient S11 is -5.80 dB to -2.20 dB.

[0082] Embodiment 6: The photosensor is a photosensor according to the preceding embodiment, which shows the characteristic that in the 75 GHz microwave reflectivity experiment of the stack, the reflection coefficient S11 is -4.90 dB to -3.10 dB.

[0083] Embodiment 7: The photoconductive material includes an inorganic photoconductive material, and the photosensor is according to any one of the preceding embodiments.

[0084] Embodiment 8: The inorganic photoconductive material includes one or more of selenium, tellurium, selenium-tellurium alloy, photoconductive metal oxide, group 4 elements or compounds, group 3-group 5 compounds, group 2-group 6 compounds, chalcogenides, pnictides, halides, and their solid solutions and / or doped modifications, and the photosensor is according to the preceding embodiment.

[0085] Embodiment 9: The chalcogenide is selected from the group including sulfide chalcogenides, selenide chalcogenides, telluride chalcogenides, ternary chalcogenides, quaternary chalcogenides, and chalcogenides with more components, and the photosensor is according to the preceding embodiment.

[0086] Embodiment 10: The chalcogenide sulfide is a photosensor according to the preceding embodiments, selected from the group consisting of lead sulfide (PbS), cadmium sulfide (CdS), zinc sulfide (ZnS), mercury sulfide (HgS), silver sulfide (Ag2S), manganese sulfide (MnS), bismuth trisulfide (Bi2S3), antimony trisulfide (Sb2S3), arsenic trisulfide (As2S3), tin(II) sulfide (SnS), tin(IV) disulfide (SnS2), indium sulfide (In2S3), copper sulfide (CuS), cobalt sulfide (CoS), nickel sulfide (NiS), molybdenum disulfide (MoS2), iron disulfide (FeS2), chromium trisulfide (CrS3), copper indium sulfide (CIS), copper indium gallium selenide (CIGS), copper zinc tin sulfide (CZTS), and solid solutions and / or their doped variants.

[0087] Embodiment 11: The chalcogenide selenide is a photosensor according to any one of the two preceding embodiments, selected from the group consisting of lead selenide (PbSe), cadmium selenide (CdSe), zinc selenide (ZnSe), bismuth triselenide (Bi2Se3), mercury selenide (HgSe), antimony triselenide (Sb2Se3), arsenic triselenide (As2Se3), nickel selenide (NiSe), thallium selenide (TlSe), copper selenide (CuSe), molybdenum diselenide (MoSe2), tin selenide (SnSe), cobalt selenide (CoSe), indium selenide (In2Se3), copper zinc tin selenide (CZTSe), and solid solutions and / or their doped variants.

[0088] Embodiment 12: The tellurized chalcogenide is a photosensor according to any one of the preceding three embodiments, selected from the group consisting of lead telluride (PbTe), cadmium telluride (CdTe), zinc telluride (ZnTe), mercury telluride (HgTe), bismuth tris telluride (Bi2Te3), arsenic tris telluride (As2Te3), antimony tris telluride (Sb2Te3), nickel telluride (NiTe), thallium telluride (TlTe), copper telluride (CuTe), molybdenum ditelluride (MoTe2), tin telluride (SnTe), and cobalt telluride (CoTe), silver telluride (Ag2Te), indium tris telluride (In2Te3), as well as solid solutions and / or their doped variants.

[0089] Embodiment 13: The ternary chalcogenide is a photosensor according to any one of the preceding four embodiments, selected from the group consisting of mercury cadmium telluride (HgCdTe), mercury zinc telluride (HgZnTe), mercury cadmium sulfide (HgCdS), lead cadmium sulfide (PbCdS), lead mercury sulfide (PbHgS), copper indium disulfide (CuInS2), cadmium sulfur selenide (CdSSe), zinc sulfur selenide (ZnSSe), thallium sulfur selenide (TlSSe), cadmium zinc sulfide (CdZnS), cadmium chromium disulfide (CdCr2S4), mercury chromium disulfide (HgCr2S4), copper chromium disulfide (CuCr2S4), cadmium lead selenide (CdPbSe), copper indium diselenide (CuInSe2), indium gallium arsenide (InGaAs), lead monoxide sulfide (Pb2OS), lead monoxide selenide (Pb2OSe), lead sulfoselenide (PbSSe), arsenic diselenide telluride (As2Se2Te), indium gallium phosphide (InGaP), gallium arsenide phosphide (GaAsP), aluminum gallium phosphide (AlGaP), cadmium selenite (CdSeO3), cadmium zinc telluride (CdZnTe), cadmium zinc selenide (CdZnSe), copper-zinc-tin-sulfur-selenium chalcogenide (CZTSSe), as well as solid solutions and / or their doped variants.

[0090] Embodiment 14: The photosensor according to any one of the preceding embodiments, wherein the photoconductive material is selected from lead chalcogenide, solid solution, and / or its doped modification.

[0091] Embodiment 15: The photosensor according to the preceding embodiment, wherein the photoconductive material is selected from lead sulfide (PbS), solid solution, and / or its doped modification.

[0092] Embodiment 16: The photosensor according to any one of the preceding embodiments, wherein the cover is an amorphous cover containing at least one metal-containing compound.

[0093] Embodiment 17: The at least one metal inclusion contains a metal or a metalloid, the metal is selected from the group consisting of lithium (Li), beryllium (Be), sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), cesium (Cs), barium (Ba), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), thallium (Tl), and bismuth (Bi), and the metalloid is selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), a photosensor according to the preceding embodiment.

[0094] Embodiment 18: The metal of the metal-containing compound contains a metal selected from the group consisting of aluminum (Al), titanium (Ti), tantalum (Ta), manganese (Mn), molybdenum (Mo), zirconium (Zr), hafnium (Hf), and tungsten (W), a photosensor according to the preceding embodiment.

[0095] Embodiment 19: The at least one metal-containing compound is selected from the group including oxides, hydroxides, chalcogenides, pnictides, carbides, or combinations thereof, a photosensor according to any one of the preceding embodiments.

[0096] Embodiment 20: The optical sensor according to any one of the preceding four embodiments, wherein the cover contains an aluminum-containing compound selected from an oxide, a hydroxide, or a combination thereof.

[0097] Embodiment 21: The optical sensor according to Embodiments 14 and 20, further showing that in wavelength-dispersive X-ray spectrometry of a stack using an electron beam microanalyzer with an acceleration voltage of 20 kV, the ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the net count / s·nA measured at the peak maximum of the Pb M α1 line is 0.113 to 0.279.

[0098] Embodiment 22: The optical sensor according to the preceding embodiments, further showing that in wavelength-dispersive X-ray spectrometry of a stack using an electron beam microanalyzer with an acceleration voltage of 20 kV, the ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the net count / s·nA measured at the peak maximum of the Pb M α1 line is 0.141 to 0.251.

[0099] Embodiment 23: The optical sensor according to the preceding embodiments, further showing that in wavelength-dispersive X-ray spectrometry of a stack using an electron beam microanalyzer with an acceleration voltage of 20 kV, the ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the net count / s·nA measured at the peak maximum of the Pb M α1 line is 0.168 to 0.224.

[0100] Embodiment 24: The optical sensor according to the preceding embodiments, further showing that in wavelength-dispersive X-ray spectrometry of a stack using an electron beam microanalyzer with an acceleration voltage of 20 kV, the ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the net count / s·nA measured at the peak maximum of the Pb M α1 line and the S K α1The photosensor according to Embodiments 15 and 20, further showing that a further ratio with the total net count / s·nA measured by a line is 0.0841 to 0.1456.

[0101] Embodiment 25: In wavelength-dispersive X-ray spectrometry of a stack using an electron beam microanalyzer and an acceleration voltage of 20 kV, the photosensor according to the preceding embodiments, further showing that a further ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the total net count / s·nA measured by the Pb M α1 line and the S K α1 line is 0.0944 to 0.1354.

[0102] Embodiment 26: In wavelength-dispersive X-ray spectrometry of a stack using an electron beam microanalyzer and an acceleration voltage of 20 kV, the photosensor according to the preceding embodiments, further showing that a further ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the total net count / s·nA measured by the Pb M α1 line and the S K α1 line is 0.1046 to 0.1251.

[0103] Embodiment 27: The cover covers the upper surface and the side surface of the layer of the photoconductive material, the photosensor according to any one of the preceding embodiments.

[0104] Embodiment 28: The cover further covers at least the side surface of the substrate, the photosensor according to the preceding embodiments.

[0105] Embodiment 29: The cover completely covers the accessible surfaces of both the layer of the photoconductive material and the side surface of the substrate, the photosensor according to any one of the preceding embodiments.

[0106] Embodiment 30: The cover is a continuous coating, the photosensor according to the preceding embodiments.

[0107] Embodiment 31: The cover is a photosensor according to any one of the preceding embodiments, having a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm.

[0108] Embodiment 32: The cover is a photosensor according to any one of the preceding embodiments, which is a conformal cover with respect to the adjacent surface of the coated layer.

[0109] Embodiment 33: The thickness of the conformal cover follows the corresponding surfaces of the photoconductive material and the substrate with a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the cover, according to the preceding embodiments.

[0110] Embodiment 34: The cover is an atomic deposition coating or a chemical vapor deposition coating, or includes the same, according to any one of the preceding embodiments.

[0111] Embodiment 35: The cover at least partially covers the electrical contact, according to any one of the preceding embodiments.

[0112] Embodiment 36: The electrical contact is preferably joinable by using a wire, particularly a gold (Au), aluminum (Al), or copper (Cu) wire, according to the preceding embodiments.

[0113] Embodiment 37: The electrical contact is joinable through the cover, according to any one of the preceding embodiments.

[0114] Embodiment 38: At least two of the electrical contacts are applied at different positions of the layer of the photoconductive material, according to any one of the preceding embodiments.

[0115] Embodiment 39: The optical sensor according to any one of the preceding embodiments, wherein the electrical contact includes at least one electrode material selected from the group consisting of silver (Ag), platinum (Pt), molybdenum (Mo), aluminum (Al), gold (Au), and graphene.

[0116] Embodiment 40: The optical sensor according to the preceding embodiment, wherein an adhesive layer is provided on the electrical contact, and the adhesive layer is suitable for adhesion.

[0117] Embodiment 41: The optical sensor according to the preceding embodiment, wherein the adhesive layer includes at least one of nickel (Ni), chromium (Cr), titanium (Ti), or palladium (Pd).

[0118] Embodiment 42: The optical sensor according to any one of the preceding embodiments, wherein the substrate has a thickness of 10 μm to 1000 μm, preferably 50 μm to 500 μm, more preferably 100 μm to 250 μm.

[0119] Embodiment 43: The optical sensor according to any one of the preceding embodiments, wherein at least one of the cover and the substrate is optically transparent within a wavelength range.

[0120] Embodiment 44: The optical sensor according to any one of the preceding embodiments, wherein the substrate is an electrically insulating substrate.

[0121] Embodiment 45: The optical sensor according to any one of the preceding embodiments, wherein the substrate includes one of glass or quartz.

[0122] Embodiment 46: The optical sensor according to any one of the preceding embodiments, wherein the substrate is directly or indirectly applied to a circuit carrier device.

[0123] Embodiment 47: The optical sensor according to any one of the preceding three embodiments, wherein the circuit carrier device is a printed circuit board.

[0124] Embodiment 48: A detector for optically detecting at least one object, at least one optical sensor according to any one of the preceding embodiments, comprising at least one sensor region and designed to generate at least one sensor signal in a manner dependent on the irradiation of the sensor region by an optical beam, the optical sensor, and at least one evaluation device designed to generate at least one information item regarding the light emission provided by the optical beam by evaluating the sensor signal of the optical sensor, the evaluation device, A detector comprising.

[0125] Embodiment 49: The detector according to the preceding embodiment, adapted to generate the sensor signal by means of one or more of measuring the electrical resistance or conductivity of at least a part of the sensor region.

[0126] Embodiment 50: The detector according to the preceding embodiment, adapted to generate the sensor signal by performing at least one current-voltage measurement and / or at least one voltage-current measurement.

[0127] Embodiment 51: The detector according to any one of the preceding embodiments related to the detector, further comprising at least one transfer device adapted to direct the optical beam to the optical sensor.

[0128] Embodiment 52: A method for manufacturing an optical sensor, comprising the following steps: a) providing a substrate, at least one layer of an optically conductive material applied to the substrate, and at least two individual electrical contacts in contact with the layer of the optically conductive material; b) subsequently depositing an amorphous cover on the accessible surface of the layer of the optically conductive material, thereby obtaining a stack comprising the substrate, the at least one layer of the optically conductive material, and the cover; c) In the quasi-static nano-indentation measurement of the stack, measuring the Young's modulus and hardness of the stack, The method for manufacturing the optical sensor is such that the optical sensor is in the quasi-static nano-indentation measurement of the stack according to step c), the Young's modulus is, 75 GPa to 107 GPa at a penetration depth of 100 nm, 47 GPa to 127 GPa at a penetration depth of 300 nm, 49 GPa to 119 GPa at a penetration depth of 1000 nm, the hardness is, 1.20 GPa to 4.70 GPa at a penetration depth of 100 nm, 1.60 GPa to 4.60 GPa at a penetration depth of 300 nm, 1.60 GPa to 8.00 GPa at a penetration depth of 1000 nm, is carried out as indicated by this, a method.

[0129] Embodiment 53: The Young's modulus is, 80 GPa to 102 GPa at a penetration depth of 100 nm, 60 GPa to 114 GPa at a penetration depth of 300 nm, 61 GPa to 107 GPa at a penetration depth of 1000 nm, the hardness is, 1.78 GPa to 4.12 GPa at a penetration depth of 100 nm, 2.10 GPa to 4.10 GPa at a penetration depth of 300 nm, 2.67 GPa to 6.93 GPa at a penetration depth of 1000 nm, The method according to the preceding embodiment.

[0130] Embodiment 54: The Young's modulus is, 86 GPa to 96 GPa at a penetration depth of 100 nm, 74 GPa to 100 GPa at a penetration depth of 300 nm, 72 GPa to 96 GPa at a penetration depth of 1000 nm, the hardness is, 2.37 GPa to 3.53 GPa at a penetration depth of 100 nm, The penetration depth is 300 nm and the pressure is 2.60 GPa to 3.60 GPa, the penetration depth is 1000 nm and the pressure is 3.73 GPa to 5.87 GPa, a method according to a preceding embodiment.

[0131] Embodiment 55: The method includes the following steps: d) determining the reflectivity coefficient S11 of the stack by applying a 75 GHz microwave reflection measurement experiment to the stack, and the reflectivity coefficient S11 is determined to be -6.70 dB to -1.30 dB; A method according to any one of the preceding embodiments referring to the method further including the above step.

[0132] Embodiment 56: A method according to a preceding embodiment, wherein the reflectivity coefficient S11 is -5.80 dB to -2.20 dB.

[0133] Embodiment 57: A method according to a preceding embodiment, wherein the reflectivity coefficient S11 is -4.90 dB to -3.10 dB.

[0134] Embodiment 58: The photoconductive material is selected from the group consisting of lead chalcogenides, solid solutions, and / or their doped variants, the cover is an amorphous cover containing an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof, and the method includes the following steps: e) performing wavelength-dispersive X-ray spectroscopy of the stack by using an electron beam microanalyzer with an acceleration voltage of 20 kV; further including, The method for manufacturing the optical sensor is performed such that in the wavelength-dispersive X-ray spectroscopy of the stack using an electron beam microanalyzer with an acceleration voltage of 20 kV, the ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the net count / s·nA measured at the peak maximum of the Pb M α1 line is 0.113 to 0.279, according to a preceding embodiment.

[0135] Embodiment 59: The Al K α1 net count / s·nA measured at the peak maximum of the line and the Pb M α1 method according to the preceding embodiment, wherein the ratio to the net count / s·nA measured at the peak maximum of the line is 0.141 to 0.251.

[0136] Embodiment 60: The Al K α1 net count / s·nA measured at the peak maximum of the line and the Pb M α1 method according to the preceding embodiment, wherein the ratio to the net count / s·nA measured at the peak maximum of the line is 0.168 to 0.224.

[0137] Embodiment 61: The photoconductive material is selected from the group consisting of lead sulfide (PbS), solid solution and / or its doped modification, and the method for manufacturing the optical sensor is such that in the wavelength-dispersive X-ray spectroscopy of the stack using the electron beam microanalyzer according to step e) with an acceleration voltage of 20 kV and the optical sensor, the net count / s·nA measured at the peak maximum of the Al K α1 line and the further ratio to the sum of the net count / s·nA measured with the Pb M α1 line and the S K α1 line is 0.0841 to 0.1456, and the method is carried out as shown, according to any one of the preceding three embodiments.

[0138] Embodiment 62: The further ratio of the net count / s·nA measured at the peak maximum of the Al K α1 line to the sum of the net count / s·nA measured with the Pb M α1 line and the S K α1 line is 0.0944 to 0.1354, and the method is according to the preceding embodiment.

[0139] Embodiment 63: The Al K α1 net count / s·nA measured at the peak maximum of the line and the Pb M α1 line and the S K α1A method according to a preceding embodiment, wherein a further ratio with the total net count / s·nA measured by the line is 0.1046 to 0.1251.

[0140] Embodiment 64: A method according to any one of the preceding embodiments referring to a method in which step b) is repeated at least once.

[0141] Embodiment 65: A method according to any one of the preceding embodiments referring to a method in which the cover is deposited until it achieves a thickness of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm.

[0142] Embodiment 66: A method according to any one of the preceding embodiments referring to a method in which the cover is deposited on the upper surface and side surfaces of the layer of the photoconductive material and at least the side surface of the substrate so as to be a conformal cover with respect to the adjacent surface of the photoconductive material or the substrate.

[0143] Embodiment 67: A method according to a preceding embodiment, wherein the thickness of the conformal cover follows the corresponding surface of the coated layer within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface of the cover.

[0144] Embodiment 68: A method according to any one of the preceding embodiments referring to a method in which at least one deposition method is used to deposit the metal-containing compound, and the at least one deposition method is preferably selected from an atomic layer deposition process, a chemical vapor deposition process, a sputtering process, or a combination thereof, and preferably an atomic layer deposition process and a combination of an atomic layer deposition process and a sputtering process.

[0145] Embodiment 69: A method according to any one of the preceding embodiments referring to a method in which step b) is performed in a vacuum chamber.

[0146] Embodiment 70: A method according to a preceding embodiment, wherein the electrical contact is provided before step b), and the cover is further partially deposited on the electrical contact.

[0147] Embodiment 71: A method according to a preceding embodiment, wherein the electrical contact is joined to at least one external connection by means of a conductive lead wire, preferably in the form of a wire, in particular using a wire of gold (Au), aluminum (Al) or copper (Cu).

[0148] Embodiment 72: A method according to a preceding embodiment, wherein the conductive lead wire is joined to the electrical contact through the cover.

[0149] Embodiment 73: Use of a detector according to any one of the preceding embodiments with reference to a detector, wherein the purpose of use is selected from the group consisting of gas sensing, fire detection, flame detection, heat detection, smoke detection, combustion monitoring, spectrometry, temperature sensing, motion sensing, industrial monitoring, chemical sensing, exhaust gas monitoring, and security applications.

Brief Description of the Drawings

[0150] Any further details and features of the present invention will become apparent from the description of the preferred exemplary embodiments that follow in connection with the dependent claims. In this context, specific features may be implemented alone or in combination with other features. The present invention is not limited to the exemplary embodiments. The exemplary embodiments are schematically shown in the figures. The same reference numerals in the individual figures refer to the same elements or elements having the same function or elements corresponding to each other with respect to their function.

[0151] Specifically, in the following figures:

Figure 1A

Figure 1B

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 3F

[0152] Exemplary embodiment FIG. 1A and FIG. 1B each highly schematically show, in side view, an exemplary embodiment of an optical sensor 110 according to the present invention. Thus, the optical sensor 110 includes a layer 112 of at least one photoconductive material 114. In particular, the layer 112 of photoconductive material 114 can exhibit a thickness of 10 nm to 100 μm, preferably 100 nm to 10 μm, more preferably 300 nm to 5 μm. In a preferred embodiment, the layer 112 of photoconductive material 114 may include an essentially flat surface, however, other embodiments are possible that may exhibit variations in the surface of layer 112, such as gradients or steps. Here, the layer 112 of photoconductive material 114 can preferably be manufactured as will be described below with respect to FIG. 3. However, other manufacturing methods are also possible.

[0153] In the exemplary embodiment of FIG. 1, the photoconductive material 114 can be at least one chalcogenide that can be preferably selected from the group including chalcogenide sulfides, chalcogenide selenides, chalcogenide tellurides, and ternary chalcogenides, or may include them. In a particularly preferred embodiment described herein, the photoconductive material 114 is a sulfide, preferably lead sulfide (PbS), its solid solution and / or its doped variants, or includes them. The preferred photoconductive material 114 is generally known to exhibit specific absorption characteristics within the infrared spectrum range, so the optical sensor 110 can preferably be used as an infrared sensor. However, other embodiments and / or other photoconductive materials for this purpose, particularly those described in other parts of this document for this purpose, are also feasible.

[0154] Furthermore, the optical sensor 110 according to the present invention includes a cover 116, which preferably completely covers the accessible surface 118 of the photoconductive material 114. As already described above, the cover 116 may be adapted to provide encapsulation to the photoconductive material 114, particularly as an airtight package, to avoid degradation of the optical sensor 110 or its compartments, particularly the photoconductive material 114, due to external influences such as humidity and / or oxygen. As described above, the cover 116 is an amorphous cover including at least one metal-containing compound 120. In a particularly preferred embodiment described herein, the metal-containing compound 120 can include at least one oxide of Al or at least one hydroxide, which can also be represented by the formula AlO x (OH) y , where 0 ≦ x ≦ 1.5 and 0 ≦ y ≦ 1.5, and x + y = 1.5. In this particular embodiment, the cover 116 can exhibit a thickness in the range of 10 nm to 600 nm, preferably 20 nm to 200 nm, more preferably 40 nm to 120 nm, and most preferably 50 to 95 nm. This thickness range particularly reflects the amount of the metal-containing compound 120 in the cover 116, which can be advantageously possible to achieve the above-mentioned function of providing encapsulation to the photoconductive material 114.

[0155] Furthermore, in this particular embodiment, the cover 116 can be a conformal cover with respect to the adjacent surface 118 of the photoconductive material 114. Thus, as defined above, the thickness of the conformal cover can follow the corresponding surface 118 of the photoconductive material 114 within a deviation of ±50 nm, preferably ±20 nm, and most preferably ±10 nm, and this deviation occurs over at least 90%, preferably at least 95%, and most preferably at least 99% of the surface 122 of the cover 116, thereby excluding any contamination or imperfection that may be present on the surface 122 of the cover 116.

[0156] As further shown in each of FIGS. 1A and 1B, at least one layer of the photoconductive material 114 is preferably applied directly to at least one substrate 124, which may preferably be or include an insulating substrate. Here, the thickness of the substrate 124 can be 10 μm to 2000 μm, preferably 50 μm to 1000 μm, and more preferably 100 μm to 500 μm. As will be described in more detail later, the substrate 124 can preferably include an optically transparent material 132, particularly glass or quartz. However, other substrate materials that can be partially or completely optically transparent within the infrared spectral range are also feasible.

[0157] According to the present invention, the substrate 124, the layer 112 of the photoconductive material 114 deposited on the substrate 124, and the cover 116 that at least covers the layer 112 of the photoconductive material 114 form a stack 125. As schematically shown in FIGS. 1A and 1B, the normal vector 126, which can be perpendicular to a certain extent of the surface of the substrate 124, can be used as a specific direction in which the stack 125 can be arranged. Thus, the substrate 124 can be considered as a base layer on which the layer 112 of the photoconductive material 114 can be arranged, and on which the cover 116 can be further arranged on the layer 112 of the photoconductive material 114 within the stack 125.

[0158] To cause the incident light beam 127 to reach the photoconductive material 114 in order to optically modify the conductivity within the layer 112 of the photoconductive material 114, at least one of the cover 116 and the substrate 124 is optically transparent in a desired wavelength range such as the infrared spectral range or a region thereof. As schematically shown in FIG. 1A, the beam path 128 of the incident light beam 127 can be configured to pass through the cover 116 in order to generate a light spot having a diameter 130 within the layer 112 of the photoconductive material 114. As a result, in particular, it can be particularly advantageous to select the metal-containing compound 120 such that the cover 116 is optically transparent, preferably within the desired wavelength range, by exhibiting appropriate absorption characteristics. Furthermore, it may be preferable in some cases that one or both of the metal-containing compound 120 used for the cover 116 and the material applied to the substrate 124 exhibit optically transparent characteristics within the desired wavelength range, such as enabling the sensing of the light beam 127 from both directions of the optical sensor 110.

[0159] The cover 116 may cover the accessible surface 118 of the photoconductive material 114 according to WO2018 / 019921A1, but according to European Patent Application 19152511.2 filed on January 18, 2019, it may further cover the accessible surface 134 of the substrate 124. Preferably, the cover 116 can be applied in such a way that it is in complete contact with all the accessible surfaces 118, 134 of the photoconductive material 114 and the substrate 124, respectively. In particular, the cover 116 may be applied so as to be in direct contact with the upper and side surfaces of the layer 112 of the photoconductive material 114 and at least the side surface of the substrate 124. However, other types for providing encapsulation of the photoconductive material 114 are possible, in particular encapsulation as an airtight package. As a result, the cover 116 thus prevents direct contact between the layer 112 of the photoconductive material 114 or the substrate 124 and the surrounding atmosphere, thereby avoiding deterioration of the photoconductive material 114 due to external influences such as humidity and / or oxygen.

[0160] As further shown in FIGS. 1A and 1B, the optical sensor 110 according to the present invention comprises at least two separate electrical contacts 136, 136', namely at least one first electrical contact 136 and at least one second electrical contact 136', which are adapted to contact the layer 112 of the photoconductive material 114. For this purpose, the electrical contacts 136, 136' may be configured and arranged such that they can conduct current from the first electrical contact 136 through the layer 112 of the photoconductive material 114 to the second electrical contact 136' or vice versa, or such that a voltage can be applied to the layer 112 of the photoconductive material 114 using the first electrical contact 136 and the second electrical contact 136'. For both purposes, the first electrical contact 136 may be electrically insulated from the second electrical contact 136', while both the first electrical contact 136 and the second electrical contact 136' are directly connected to the layer 112 of the photoconductive material 114. As further illustrated herein, the cover 116 can be configured to at least partially cover the electrical contacts 136, 136' such that the electrical contacts 136, 136' can be coupled to one or more leads 138, 138' etc. that may be connected to an external circuit, as particularly shown in FIG. 1B.

[0161] A direct connection between any one of the electrical contacts 136, 136' and the layer 112 of the photoconductive material 114 can be provided by any known process capable of providing electrical contacts, such as plating, welding, soldering, wire bonding, ultrasonic thermocompression bonding, stitch bonding, ball bonding, wedge bonding, compliant bonding, thermocompression bonding, anodic bonding, direct bonding, plasma-activated bonding, eutectic bonding, glass frit bonding, adhesive bonding, transient liquid phase diffusion bonding, surface-activated bonding, tape automated bonding, or depositing a highly conductive substance in the contact area. While enabling sufficient electrical conductivity through the electrical contacts 136, 136', the electrical contacts 136, 136' preferably comprise at least one electrode material selected from the group consisting of silver (Ag), copper (Cu), platinum (Pt), aluminum (Al), molybdenum (Mo), or gold (Au), an alloy containing at least one of said metals, and graphene, in order to provide sufficient mechanical stability of the electrical contacts 136, 136' at the same time. However, other types of electrode materials are also feasible.

[0162] As schematically shown in FIG. 1B, the substrate 124 may preferably be attached to the circuit carrier device 142, in particular a printed circuit board (PCB) 144, via a thin film 140 of an adhesive. For this purpose, wires such as gold wires, beryllium-doped wires, aluminum wires, platinum wires, palladium wires, silver wires, or copper wires may be used as leads 138, 138' for connecting electrical contacts 136, 136', such as contact pads (not shown here) on the circuit carrier device 142. In a particularly preferred embodiment as shown in FIG. 1B, the electrical contacts 136, 136' may be connectable through the cover 116. This feature may in particular enable improving the encapsulation function of the cover 116 and at the same time providing stability to the electrical contacts 136, 136'.

[0163] Furthermore, according to the present invention, the stack 125 included by the optical sensor 110 can exhibit particularly selected static mechanical properties 145. Here, the static mechanical property 145, which refers to the response of the stack 125 to the incident static force applied to the stack 125, is accessible by performing a quasi-static nano-indentation measurement on the body, as will be described in more detail with respect to FIG. 3C. As shown therein, the Young's modulus and hardness of the stack 125 at particularly selected penetration depths, specifically 100 nm, 300 nm, and 1000 nm, can be considered as reliable indicators for determining the static mechanical property 145 of the stack 125 included by the optical sensor 110. As already shown above, surprisingly, it has been found that the optical sensor 110 exhibits favorable static mechanical properties 145 when the stack 125 has the following properties, that is, in the quasi-static nano-indentation measurement of the stack 125, the Young's modulus is 75 GPa to 107 GPa at a penetration depth of 100 nm, preferably 80 GPa to 102 GPa, more preferably 86 GPa to 96 GPa, 47 GPa to 127 GPa at a penetration depth of 300 nm, preferably 60 GPa to 114 GPa, more preferably 74 GPa to 100 GPa, 49 GPa to 119 GPa at a penetration depth of 1000 nm, preferably 61 GPa to 107 GPa, more preferably 72 GPa to 96 GPa, On the other hand, the hardness is 1.20 GPa to 4.70 GPa at a penetration depth of 100 nm, preferably 1.78 GPa to 4.12 GPa, more preferably 2.37 to 3.53 GPa, 1.60 GPa to 4.60 GPa at a penetration depth of 300 nm, preferably 2.10 GPa to 4.10 GPa, more preferably 2.60 GPa to 3.60 GPa, When the penetration depth is 1000 nm and the pressure is 1.60 GPa to 8.00 GPa, preferably 2.67 GPa to 6.93 GPa, and more preferably 3.73 GPa to 5.87 GPa, the optical sensor 110 is found to exhibit preferable static mechanical properties 145.

[0164] Furthermore, the stack 125 included by the optical sensor 110 can preferably exhibit particularly selected dielectric properties 146. Here, the dielectric properties 146, which refer to the response of the stack 125 to the incident electromagnetic wave applied to the stack 125, can be accessed by the microwave reflectivity experiment to be described in more detail later with respect to FIG. 3D. As a result, the S11 reflectivity coefficient can be considered as a reliable indicator for determining the dielectric properties 146 of the stack 125 included by the optical sensor 110. As already described, surprisingly, when the stack 125 has the following properties, that is, in the 75 GHz microwave reflectivity experiment of the stack, the reflectivity coefficient S11 is -6.70 dB to -1.30 dB, preferably -5.80 dB to -2.20 dB, and more preferably -4.90 dB to -3.10 dB, the optical sensor 110 is found to exhibit preferable dielectric properties 146.

[0165] Furthermore, the stack 125 included by the optical sensor 110 can preferably exhibit particularly selected composition 148. As will be described in more detail later with respect to FIG. 3, the wavelength-dispersive X-ray spectroscopy (WDXS) of the stack 125 can preferably be employed to determine the characteristics of the composition 148 of the stack 125. Here, the photoconductive material 114 used for the optical sensor 110 can preferably be a lead chalcogenide, a solid solution, and / or a doped variant thereof, and the lead chalcogenide can specifically be lead sulfide (PbS). At the same time, the cover 116 can be an amorphous cover containing an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof, also denoted as "Al2O3". Thereby, the net count of the WDXS measurement of the stack 125, as will be described in more detail below with respect to FIG. 3E, is the peak maximum of the Al K α1 line, Pb Mα1 The peak maximum value of the line, and SK α1 It can be determined respectively by the peak maximum value of the line. As already shown above, surprisingly, when the optical sensor 110 includes the composition 148 confirmed by the WDXS measurement of the stack 125 using an electron beam microanalyzer with an acceleration voltage of 20 kV, that is, Al K α1 The net count / s·nA measured at the peak maximum value of the line, and Pb M α1 The ratio of the net count / s·nA measured at the peak maximum value of the line to that of Pb M is 0.113 to 0.279, preferably 0.141 to 0.251, more preferably 0.168 to 0.224. On the other hand, in a specific case where PbS is used as a specific lead chalcogenide, Al K α1 The net count / s·nA measured at the peak maximum value of the line, and Pb M α1 The line and SK α1 The further ratio to the sum of the net count / s·nA measured at the line of SK is 0.0841 to 0.1456, preferably 0.0944 to 0.1354, more preferably 0.1046 to 0.1251, and it has been found that favorable characteristics are shown in this case.

[0166] FIG. 2 shows an exemplary embodiment of a photodetector 150 according to the present invention, in a very schematic way, preferably adapted for use as an infrared detector. However, other embodiments are also feasible. The photodetector 150 includes at least one of the optical sensors 100 as described in more detail above, and the optical sensor 100 may be arranged along the optical axis of the detector 150. Specifically, the optical axis may be the axis of symmetry and / or the axis of rotation of the configuration of the optical sensor 100. The optical sensor 100 may be arranged within the housing of the detector 150. Further, at least one transfer device may be included, preferably a refractive lens. The opening of the housing, which may be arranged concentrically with respect to the optical axis, preferably may define the viewing direction of the detector 150.

[0167] Furthermore, the optical sensor 100 is designed to generate at least one sensor signal in a way that depends on the irradiation of the sensor area 152 by the optical beam 127. Here, the detector 150 may have a straight beam path or an inclined beam path, an angled beam path, a branched beam path, a deflected or split beam path, or other types of beam paths. Furthermore, the optical beam 127 can propagate once or repeatedly, in one direction or in both directions, along each beam path or partial beam path.

[0168] According to the FiP effect, the optical sensor 100 can provide a sensor signal that depends on the beam cross-sectional area 130 of the optical beam 127 within the sensor area, assuming the same total irradiation output. However, other types of signals are also possible. As shown above, the sensor area 152 may include at least one of the layers 112 of the photoconductive material 114, preferably including lead chalcogenide, solid solution, and / or its doped variants, and the lead chalcogenide may specifically be lead sulfide (PbS). However, other photoconductive materials 114, particularly other chalcogenides, may also be used. As a result of the use of the photoconductive material 114 in the sensor area 152, the electrical conductivity of the sensor area 152 depends on the beam cross-section of the optical beam 127 in the sensor area, assuming the same total output of irradiation. As a result, the resulting sensor signal provided by the optical sensor 110 upon collision with the optical beam 127 may depend on the electrical conductivity of the photoconductive material 114 in the sensor area 152, and thus makes it possible to determine the beam cross-sectional area 130 of the optical beam 127 in the sensor area 152.

[0169] The sensor signal may be transmitted to an evaluation device 156 via further electrical leads 154, 154' to which leads 138, 138' are joined, and the evaluation device 156 is generally designed to generate at least one item of information by evaluating the sensor signal of the optical sensor 110. For this purpose, the evaluation device 156 may comprise one or more electronic devices and / or one or more software components for evaluating the sensor signal. Generally, the evaluation device 156 may be part of a data processing device 158 and / or may include one or more data processing devices 158. The evaluation device 156 may be integrated completely or partially into the housing and / or may be embodied as a separate device that is electrically connected to the optical sensor 100 in a wireless or wired manner, completely or partially. The evaluation device 156 may further include one or more additional components, such as one or more measurement units and / or one or more evaluation units and / or one or more control units (not shown here), etc., one or more electronic hardware components and / or one or more software components.

[0170] Figs. 3A to 3F show, in a very schematic way, exemplary embodiments of a method for manufacturing an optical sensor 110 according to the invention.

[0171] As shown in Fig. 3A, a substrate 124 is provided as a base layer, and further layers are deposited successively thereon. Here, the normal vector 126 perpendicular to the extent of the surface of the substrate 124 can be used as a specific direction in which the stack 125 can be arranged. Preferably, before providing a layer 112 of a photoconductive material 114 containing glass as the optically transparent material 132, electrical contacts 136, 136' may be generated on the substrate 124 in the form of a vapor-deposited metal layer that can be provided by known vapor deposition techniques. In particular, the vapor-deposited metal layer may include one or more of Ag, Al, Pt, Mg, Cr, Ti, or Au. Alternatively, the electrical contacts 136, 136' may include a layer of graphene. However, as described in more detail above, other methods of generating the electrical contacts 136, 136' are also feasible.

[0172] As further shown in FIG. 3A, a layer 112 of the photoconductive material 114 is subsequently provided. For this purpose, the photoconductive material 114 can be synthesized according to the following procedure. As a result, 0.015 mol / L of thiourea or its substituted product, 0.015 mol / L of lead acetate, lead nitrate or its substituted product, and 0.15 mol / L of sodium hydroxide or its substituted product are dissolved in the reaction volume, whereby a transparent solution is obtained at room temperature. As is known from the prior art, when the above solutions are mixed in any order, lead sulfide (PbS) will precipitate from the solution at a temperature above 30° C. in a manner such that a generally uniform and relatively smooth layer is formed on the sidewalls and bottom of the liquid-containing reactor or on the walls of any object located therein.

[0173] However, immediately before lead sulfide (PbS) actually precipitates from the mixed precipitation solution, an additive capable of degassing a relatively large amount of nascent oxygen, preferably an aqueous solution of potassium persulfate, hydrogen peroxide, or sodium perborate, is added thereto, and lead sulfide (PbS) precipitates therefrom in the usual manner, but in an activated form that allows for further sensitization by direct use within the cell or by aging or low-temperature baking. The precipitation solution and the activator are preferably mixed at a temperature above 35° C. and stirred for 1 to 3 hours, during which deposition occurs. Here, the amount of nascent oxygen from persulfate ions, perborate ions, or hydrogen peroxide added to the solution to precipitate PbS is preferably 0.01 to 0.5 times the theoretical amount of PbS in the bath in moles, where the theoretical amount of PbS is the amount formed in the case of complete conversion of the lead and sulfur precipitation compounds to lead sulfide.

[0174] After the formation of the lead sulfide (PbS) layer, an aging step can optionally be carried out in an artificial climate chamber, preferably at a temperature of about 50° C. and a humidity above 70%, which has been found to be beneficial for the photoconductive performance. Improved photoconductivity can be obtained if the deposited and aged film is further treated by annealing, i.e., heating at a temperature of about 100° C. to 150° C. for 1 to 100 hours in vacuum or air.

[0175] However, other types of methods for providing the layer 112 of the photoconductive material 114 may also be feasible.

[0176] FIG. 3B schematically shows depositing a metal-containing compound 120 as an amorphous cover 116 on accessible surfaces 118, 134 of a layer 112 of a photoconductive material PbS 114 and a substrate 124, particularly to function as an encapsulation layer. For this purpose, at least one precursor adapted to react with the metal-containing compound 120 can be adapted. In this preferred embodiment, an atomic layer deposition (ALD) process, or a combination of ALD and sputtering, is used as the deposition method. Alternatively, other deposition processes such as a chemical vapor deposition (CVD) process can also be applied.

[0177] In a preferred embodiment of the present invention, the cover 116 comprises Al2O3 produced by an ALD process or a combination of an ALD process and a sputtering process. Alternatively, laminates such as Al2O3 / TiO2 / Al2O3 / ... or Al2O3 / ZrO2 / Al2O3 / ... can also be produced. In this particular embodiment, the ALD process has the following process parameters First precursor: H2O; Second precursor: Al(CH3)3 (trimethylaluminum, TMA); Temperature of about 60 °C; About 700 cycles and was executed by applying.

[0178] As further shown in FIG. 3B, an Al2O3-containing cover 116 can be applied according to the present invention in such a way as to simultaneously cover the accessible surface 118 of the photoconductive PbS layer 112, electrical contacts 136, 136' that can contact the photoconductive PbS layer 112, and the accessible surface 134 of the substrate 124.

[0179] As further shown in FIG. 3B, stack 125 is now obtained by providing substrate 124, depositing layer 112 of photoconductive material 114 on substrate 124, and subsequently depositing cover 116 at least over layer 112 of photoconductive material 114. As schematically shown in FIG. 3B, normal vector 126, which is perpendicular to the extent of the surface of substrate 124, is used herein as a specific direction of the arrangement of stack 125.

[0180] According to the present invention, stack 125 exhibits specifically selected static mechanical properties 145 with respect to the response of stack 125 to an incident static force applied to stack 125. Here, the specifically selected static mechanical properties 145 of stack 125 are determined by measuring the Young's modulus and hardness of stack 125 in a quasi-static nanoindentation measurement. As schematically shown in FIG. 3C, the quasi-static nanoindentation measurement preferably includes the measurement of the Young's modulus of the body and the measurement of hardness, performed in accordance with standards EN ISO 14577-1:2015 and EN ISO 14577-4:2016. For this purpose, nanoindenter 160 is used, and the nanoindenter includes a probe 162 having a tip 164 designed to penetrate into a very small volume 166 of stack 125 in order to perform a quasi-static nanoindentation measurement. For this purpose, the tip 164 of nanoindenter 160 preferably has a pyramid shape, and in particular, a Berkovich tip 168 in accordance with the EN ISO 14577-2:2015 standard is preferred. Thus, the Young's modulus and hardness of stack 125 are measured by using nanoindenter 160, thereby measuring the preferred static and dynamic mechanical properties 145, 146 of stack 125 presented in more detail above. However, if the Young's modulus and hardness of stack 125 measured by nanoindenter 160 deviate from the preferred static mechanical properties 145 of stack 125 as described above, the specific sample of optical sensor 110 may be rejected from further use in photodetector 150.

[0181] Quasistatic nanoindentation measurements of Young's modulus and hardness at each penetration depth of 100 nm, 300 nm, and 1000 nm were each performed using a Berkovich tip with 30 individual optical sensors selected according to the selection criteria shown in more detail above. Thus, the selection criteria were defined as optical sensor 110 having a relative dark resistance change of less than 0.1%, a relative detection sensitivity change of less than 0.1%, and an absolute maximum deviation of dark resistance from linear resistance between -10 V and +10 V of less than 0.1%. As shown in Table 1, the following values sorted by size were obtained from these quasistatic nanoindentation measurements:

[0182] [Table 1]

[0183] Based on these results, the following parameters as shown in Table 2 can be determined, where each value after the symbol "±" indicates ±1.5σ and σ refers to the corresponding standard deviation.

[0184] [Table 2]

[0185] Further according to the invention, the stack 125 may exhibit a specifically selected dielectric property 146 in terms of the response of the stack 125 to an incident electromagnetic wave applied to the stack 125. Here, the specifically selected dielectric property 146 of the stack 125 may be determined in a microwave reflection measurement experiment. As shown diagrammatically in FIG. 3D, the dielectric property 146 of the stack 125 is determined by measuring the S11 reflectance coefficient in a microwave reflection measurement experiment using a microwave device 170. Here, the microwave device 170 may comprise a microwave emitter 172 that generates and emits an incident microwave 174 at a frequency of 75 GHz. The incident microwave 174 may impinge on the stack 125, which then reflects a portion of the incident microwave 174 as a reflected microwave 176, which may be detected by a microwave receiver 178. The microwave evaluation unit 180 may measure the dielectric property 146 in dB. 10 log(P refl / P in ) where P in is the power of the incident microwave 174 provided by the microwave emitter 172 impinging on the stack 125, and P refl is the power of the reflected microwave 176 reflected by the stack 125 and measured by the microwave receiver 178. As a result, by measuring the S11 reflectance coefficient, the dielectric properties 146 of the stack 125 can be reliably determined. However, if the S11 reflectance coefficient of the stack 125 measured by the microwave device 170 possibly deviates from the preferred dielectric properties 146 of the stack 125 as indicated above, then that particular sample of the optical sensor 110 may be rejected from further use in the optical detector 150. The following values, sorted by size as shown in Table 3, were obtained from microwave reflectance measurement experiments on 30 individual optical sensors selected according to the selection criteria as indicated above:

[0186] [Table 3]

[0187] Based on these results, the measured value of the S11 reflectivity coefficient can be determined to be -4.00 dB ± 2.70 dB, where each value after "±" represents 1.5σ, and σ refers to the corresponding standard deviation.

[0188] In a particularly preferred embodiment, the photoconductive material 114 may specifically include lead chalcogenide, particularly lead sulfide (PbS), solid solution, and / or its doped variants. At the same time, the cover 116 may be an amorphous cover containing Al2O3. Here, wavelength-dispersive X-ray spectroscopy (WDXS) enables the determination of the composition 148 of the stack 125 including the Al2O3 cover 116 covering the PbS layer 112 deposited on the glass substrate 124. As shown in FIG. 3E, the WDXS measurement can preferably be performed using an electron beam microanalyzer 182. The electron beam microanalyzer 182 can include an electron source 184 for generating an incident electron beam 186, and the incident electron beam 186 collides with the stack 125. As a result, the stack 125 emits an X-ray beam 188, and the X-ray beam 188 may then be collimated by a collimator 190 to irradiate a known single crystal 192 at an accurate angle. The single crystal 192 diffracts the X-ray beam 188 into a diffracted X-ray beam 194, which is collected by a detector 196.

[0189] Here, the single crystal 192, the stack 125, and the detector 196 may be accurately attached to a goniometer (not shown here), and the distance between the stack 125 and the single crystal 192 may be equal to the distance between the single crystal 192 and the detector 196. Preferably, an acceleration voltage of 20 kV may be used for the incident electron beam 186. Further, an automatic exchange unit (not shown here) for exchanging the single crystal 192 according to the energy of the incident electron beam 186 in particular may be used, thereby enabling the analysis of different components within the composition 148 of the stack 125.

[0190] By using the WDXS evaluation unit 200, the net count of the WDXS measurement is Al Kα1 Peak maximum value of the line, Pb M α1 Peak maximum value of the line, and S K α1 It can be determined respectively at the peak maximum value of the line, whereby the composition 148 of the stack 125 can be confirmed. However, if the peak maximum value of the indicated line measured by the electron beam microanalyzer 182 deviates from the preferred value as described above, a particular sample of the optical sensor 110 can be rejected from further use in the photodetector 150.

[0191] To characterize the composition 148 of the Al2O3 / PbS layer, WDXS measurements were performed using a commercially available electron beam microanalyzer, and the material of the single crystal 192 was Al K α1 For the measurement of the line, from potassium phthalate (TAP), Pb M α1 Line and S K α1 For the measurement of the line, they were respectively selected from H-type pentaerythritol (PET H). For the WDXS measurement, an acceleration voltage of 20 kV, a beam current of 150 nA, a measurement time of 100 seconds at the maximum peak, a measurement time of 20 seconds for the background on both sides of the peak, and a measurement spot diameter of 300 μm were used. All net counts of the WDXS measurement were determined at the peak maximum value of each of the Al K α1 Line, Pb M α1 Line, and S K α1 Line. In the specific electron beam microanalyzer 182 used for the WDXS measurement, in the case of Al measurement, the net count of the Al K α1 Line was measured at 90.918 mm, and in the case of Pb measurement, the net count of the Pb M α1 Line was measured at 169.291 mm, and in the case of S measurement, the net count of the S K α1 Line was measured at 172.124 mm. As shown in Table 4, the following values sorted by size were obtained from the WDXS experiments for 30 individual optical sensors selected according to the above selection criteria.

[0192]

Table 4

[0193] The gross count ratio of Al / Pb was determined to be 0.196 ± 0.83, while the net count ratio of Al / (Pb + S) was determined to be 0.1142 ± 0.3075. In both cases, each value after "±" represents 1.5σ, where σ refers to the corresponding standard deviation.

[0194] As shown in Figure 3F, two electrical contacts 136, 136' that are in electrical contact with the layer 112 of the photoconductive material 114 may preferably be joined to at least one external connection by conductive lead wires 138, 138' such as gold wires provided via the cover 116. However, as described above, other methods for providing the electrical contacts 136, 136' to the photoconductive PbS layer 112 are also feasible. For example, it is feasible by providing the lead wires 138, 138' already before depositing the amorphous cover 116, i.e., at an intermediate method step between the method steps as shown in Figures 3A and 3B. After manufacturing, the stack 125 can be rotated in any direction as a whole, which can have no effect on the arrangement and composition 148 of the stack 125.

[0195] List of reference numerals 110 Sensor 112 Layer of photoconductive material 114 Photoconductive material 116 Cover 118 Accessible surface of the layer of photoconductive material 120 Metal-containing compound 122 Surface of the cover 124 Substrate 125 Stack 126 Normal vector 127 Light beam 128 Beam path 130 Diameter of the light beam, beam cross-sectional area 132 Optically transparent material 134 Accessible surface of the substrate 136, 136' Electrical contacts 138, 138' Electrical connection leads 140 Thin film of adhesive 142 Circuit carrier device 144 Printed circuit board 145 Static mechanical properties 146 Dielectric properties 148 Composition 150 Photodetector 152 Sensor area 154, 154' Further electrical lead wires 156 Evaluation device 158 Processing device 160 Nanoindenter 162 Probe 164 Chip 166 Volume 168 Berkovitch tip 170 Microwave device 172 Microwave emitter 174 Incident microwave 176 Reflected microwave 178 Microwave receiver 180 Microwave evaluation unit 182 Electron beam microanalyzer 184 Electron source 186 Incident electron beam 188 Emitted X-ray beam 190 Collimator 192 Single crystal 194 Diffracted X-ray beam 196 X-ray detector 198 Spot diameter 200 WDXS evaluation unit

Claims

1. An optical sensor (110) comprising a stack (125), wherein the stack (125) comprises: a substrate (124), a layer (112) of at least one photoconductive material (114) applied on the substrate (124), a cover (116) covering the accessible surface of the photoconductive material (114), at least two separate electrical contacts (126, 136') spatially separated from the stack (125) and in contact with the layer (112) of the photoconductive material (114), and in a quasi-static nanoindentation measurement of the stack (125), the optical sensor (110) has a Young's modulus that is 75 GPa to 107 GPa at an indentation depth of 100 nm, is 47 GPa to 127 GPa at an indentation depth of 300 nm, is 49 GPa to 119 GPa at an indentation depth of 1000 nm, a hardness that is 1.20 GPa to 4.70 GPa at an indentation depth of 100 nm, is 1.60 GPa to 4.60 GPa at an indentation depth of 300 nm, is 1.60 GPa to 8.00 GPa at an indentation depth of 1000 nm, indicating that, the optical sensor (110).

2. In a quasi-static nanoindentation measurement of the stack (125), the optical sensor (110) has a Young's modulus that is 80 GPa to 102 GPa at an indentation depth of 100 nm, is 60 GPa to 114 GPa at an indentation depth of 300 nm, is 61 GPa to 107 GPa at an indentation depth of 1000 nm, a hardness that is 1.78 GPa to 4.12 GPa at an indentation depth of 100 nm, is 2.10 GPa to 4.10 GPa at an indentation depth of 300 nm, is 2.67 GPa to 6.93 GPa at an indentation depth of 1000 nm, indicating that, the optical sensor (110) according to Claim 1.

3. In a 75 GHz microwave reflection measurement experiment of the stack (125), the optical sensor (110) according to Claim 1 or 2, wherein the reflectivity coefficient S11 is -6.70 dB to -1.30 dB.

4. In a 75 GHz microwave reflectivity measurement experiment of the stack (125), the optical sensor (110) according to Claim 3, wherein the reflectivity coefficient S11 is -5.80 dB to -2.20 dB.

5. The optical sensor (110) according to any one of Claims 1 to 4, wherein the cover (116) comprises an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof.

6. The photosensor (110) according to any one of claims 1 to 5, wherein the photoconductive material (114) is selected from lead chalcogenides, solid solutions, and / or doped variants thereof.

7. The optical sensor (110) is used in wavelength-dispersive X-ray spectrometry of the stack (125) with an acceleration voltage of 20 kV in an electron beam microanalyzer (182), and Al K α１ The optical sensor (110) according to claim 5 or 6, further showing that the ratio of the net count / s·nA measured at the peak maximum value of the line to the net count / s·nA measured at the peak maximum value of the Pb M α１ line is 0.113 to 0.

279.

8. The optical sensor (110) is used in wavelength-dispersive X-ray spectroscopy of the stack (125) with an acceleration voltage of 20 kV in an electron beam microanalyzer (182), and Al K α１ The optical sensor (110) according to claim 7, further showing that the ratio of the net count / s·nA measured at the peak maximum of the line to the net count / s·nA measured at the peak maximum of the Pb M α１ line is 0.141 to 0.

251.

9. The photosensor (110) according to any one of claims 5 to 8, wherein the photoconductive material (114) is selected from lead sulfide (PbS), solid solutions, and / or doped variants thereof.

10. The optical sensor (110) is used in wavelength-dispersive X-ray spectrometry of the stack (125) with an acceleration voltage of 20 kV in an electron beam microanalyzer (182), and Al K α１ The optical sensor (110) according to any one of claims 1 to 9, further showing that a further ratio of the net count / s·nA measured at the peak maximum value of the line to the sum of the net count / s·nA measured with the Pb M α１ line and the S K α１ line is 0.0841 to 0.1456.

11. The optical sensor (110) is used in wavelength-dispersive X-ray spectroscopy of the stack (125) with an acceleration voltage of 20 kV in an electron beam microanalyzer (182), and Al K α１ The optical sensor (110) according to claim 10, further showing that a further ratio of the net count / s·nA measured at the peak maximum value of the line to the sum of the net count / s·nA measured by the Pb M α１ line and the S K α１ line is 0.0944 to 0.1354.

12. A detector (150) for optical detection, comprising: - At least one photosensor (110) according to any one of claims 1 to 11, including at least one sensor region (152) and designed to generate at least one sensor signal in a manner dependent on the irradiation of the sensor region (152) by a light beam (127); and - At least one evaluation device (156) designed to generate at least one information item regarding the light radiation provided by the light beam (127) by evaluating the sensor signal of the photosensor (110). The detector (150) comprising the above.

13. A method for manufacturing a photosensor (100), comprising the following steps: a) Providing a substrate (124), a layer (112) of at least one photoconductive material (114) applied to the substrate (124), and at least two individual electrical contacts (136, 136') in contact with the layer (112) of the photoconductive material (114); b) Subsequently, depositing a cover (116) on an accessible surface of the layer (112) of the photoconductive material (114), thereby obtaining a stack (125) comprising the substrate (124), the layer (112) of the at least one photoconductive material (114), and the cover (116); c) Measuring the Young's modulus and hardness of the stack (125) in a quasi-static nanoindentation measurement. In the method for manufacturing the photosensor (110), when the photosensor (110) is subjected to the quasi-static nanoindentation measurement of the stack (125) in step c), the Young's modulus is 75 GPa to 107 GPa at an indentation depth of 100 nm, 47 GPa to 127 GPa at an indentation depth of 300 nm. At a penetration depth of 1000 nm, it is 49 GPa to 119 GPa, and the hardness is at a penetration depth of 100 nm, it is 1.20 GPa to 4.70 GPa, at a penetration depth of 300 nm, it is 1.60 GPa to 4.60 GPa, at a penetration depth of 1000 nm, it is 1.60 GPa to 8.00 GPa, a method performed as indicated.

14. The method comprising the following steps: d) determining the reflectivity coefficient S11 of the stack (125) by applying a microwave reflection measurement experiment at 75 GHz to the stack, and the step in which the reflectivity coefficient S11 is determined to be -6.70 dB to -1.30 dB, The method according to claim 13, further comprising.

15. The photoconductive material (114) is selected from the group consisting of lead chalcogenides, solid solutions and / or their doped modifications, the cover (116) contains an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof, and the method comprises the following steps: e) performing wavelength-dispersive X-ray spectroscopy of the stack (125) using an electron beam microanalyzer (182) with an acceleration voltage of 20 kV, further comprising Al K α１ The net counts / s·nA measured at the peak maximum of the line, and Pb M α１ The method according to claim 14, wherein the ratio of the net counts / s·nA measured at the peak maximum of the line is determined to be 0.113 to 0.

279.

16. The photoconductive material (114) is selected from the group consisting of lead sulfide (PbS), solid solutions and / or doped variants thereof, and further by step e), Al K α１ The further ratio of the net counts / s·nA measured at the peak maximum of the Al K α１ line to the sum of the net counts / s·nA measured at the Pb M α１ line and the S K line is from 0.0841 to 0.1456, the method according to claim 15.

17. A method of selecting an optical sensor (110) having overall long-term quality, the following steps, - providing an optical sensor (110) comprising a stack (125), the stack (125) comprising a substrate (124), a layer (112) of at least one photoconductive material (114) applied to the substrate (124), a cover (116) covering the accessible surface of the photoconductive material (114), at least two individual electrical contacts (136, 136') spatially separated from the stack (125) and in contact with the layer (112) of the photoconductive material (114), - measuring the Young's modulus and hardness of the stack (125) in a quasi-static nanoindentation measurement, - in the quasi-static nanoindentation measurement of the stack (125), the Young's modulus is at a penetration depth of 100 nm, it is 75 GPa to 107 GPa, at a penetration depth of 300 nm, it is 47 GPa to 127 GPa, at a penetration depth of 1000 nm, it is 49 GPa to 119 GPa, and the hardness is at a penetration depth of 100 nm, it is 1.20 GPa to 4.70 GPa, at a penetration depth of 300 nm, it is 1.60 GPa to 4.60 GPa, At a penetration depth of 1000 nm, it is 1.60 GPa to 8.00 GPa, The penetration depth is determined with respect to the surface of the stack (125), Selecting an optical sensor (110) in which the stack exhibits favorable static mechanical properties (145), Or, when the Young's modulus and hardness of the stack (125) deviate from the favorable static mechanical properties of the stack (125), rejecting the optical sensor (110), a method comprising the steps of.

18. The favorable static mechanical properties (145) of the stack (125) are in the quasi-static nanoindentation measurement of the stack (125), The Young's modulus is, At a penetration depth of 100 nm, it is 80 GPa to 102 GPa, At a penetration depth of 300 nm, it is 60 GPa to 114 GPa, At a penetration depth of 1000 nm, it is 61 GPa to 107 GPa, The hardness is, At a penetration depth of 100 nm, it is 1.78 GPa to 4.12 GPa, At a penetration depth of 300 nm, it is 2.10 GPa to 4.10 GPa, At a penetration depth of 1000 nm, it is from 2.67 GPa to 6.93 GPa, Including this, the method according to claim 17.

19. The favorable static mechanical properties (145) of the stack (125) include that in the 75 GHz microwave reflection measurement experiment of the stack (125), the reflectivity coefficient S11 is -6.70 dB to -1.30 dB, the method according to claim 17 or 18.

20. The favorable static mechanical properties (145) of the stack (125) include that in the 75 GHz microwave reflection measurement experiment of the stack (125), the reflectivity coefficient S11 is -5.80 dB to -2.20 dB, the method according to claim 18.

21. The cover (116) includes an aluminum-containing compound selected from oxides, hydroxides, or combinations thereof, the method according to any one of claims 17 to 20.

22. The photoconductive material (114) is selected from lead chalcogenides, solid solutions, and / or their doped modifications, the method according to any one of claims 17 to 21.

23. The preferred static mechanical property (145) of the stack (125) is the net count / s·nA measured at the peak maximum of the Al K α１ line and the ratio of the net count / s·nA measured at the peak maximum of the Pb M α１ line being 0.113 to 0.279 in wavelength dispersive X-ray spectrometry of the stack (125) using an electron beam microanalyzer (182) and an acceleration voltage of 20 kV, the method according to claim 21 or 22.

24. Preferred static mechanical properties (145) of the stack (125) are, in wavelength dispersive X-ray spectroscopy of the stack (125) using an electron beam microanalyzer (182) and an acceleration voltage of 20 kV, Al K α１ the ratio of the net counts / s·nA measured at the peak maximum of the line to the net counts / s·nA measured at the peak maximum of the Pb M α１ line being from 0.141 to 0.251, the method according to claim 23.

25. The photoconductive material (114) is selected from lead sulfide, solid solutions, and / or their doped modifications, the method according to any one of claims 21 to 24.

26. The preferred static mechanical properties (145) of the stack (125) include, in wavelength dispersive X-ray spectroscopy of the stack (125) using an electron beam microanalyzer (182) and an acceleration voltage of 20 kV, Al K α１ the net count / s·nA measured at the peak maximum of the line, and Pb M α１ the sum of the net count / s·nA measured with the line and S K α１ the method according to any one of claims 17 to 25, including that the further ratio to the line is 0.0841 to 0.1456.

27. The preferred static mechanical properties (145) of the stack (125) are such that in wavelength dispersive X-ray spectroscopy of the stack (125) using an electron beam microanalyzer (182) and an acceleration voltage of 20 kV, the net count / s·nA measured at the peak maximum of the Al K α１ line and the further ratio to the sum of the net count / s·nA measured with the Pb M α１ line and the S K α１ line are from 0.0944 to 0.1354, the method according to claim 26.

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