Photodetectors with improved detection results

Abstract

The present invention relates to various aspects of a photodetector (1-8) for the spectrally selective detection of electromagnetic radiation, comprising a first optoelectronic device (100-106, 108) for the detection of a first wavelength of electromagnetic radiation, the first optoelectronic device (100-106, 108) having a first optical cavity and at least one detector cell (21, 21a, 22, 22a, 23) arranged in the first optical cavity, the first optical cavity being formed by two parallel, spaced apart mirror layers (11, 11a, 11', 12, 12a), the length of the first optical cavity being designed such that a resonant wave (13, 13a) of order i associated with the first wavelength forms in the first optical cavity. Each detection cell (21, 21a, 22, 22a, 23) includes a photoactive layer (210, 220, 230) disposed within a first optical cavity such that exactly one vibration maximum of the resonant wave (13, 13a) is present within the photoactive layer (210, 220, 230), respectively. According to a first aspect of the invention, the resonant wave of the first optoelectronic device (100-106, 108) has an order greater than 1, and at least one optically absorbing intermediate layer (30, 31) and / or at least one optically transmissive contact layer (50) is disposed within the optical cavity. According to a second aspect, the first optoelectronic device (110, 110') comprises, in addition to the detector cell (21, 21'), at least one optically transparent spacer layer (40) and at least one external contact (60, 60'), the spacer layer being disposed within the first optical cavity between one of the mirror layers (11, 12) and the detector cell (21, 21'), and the external contact being in contact with the outer surface of the detector cell (21, 21') and made of an electrically conductive material.

Description

[Technical field]

[0001] The present invention relates to a photodetector for the spectrally selective detection of electromagnetic radiation, comprising an optoelectronic device with an optical cavity and at least one detection cell arranged therein and enabling improved detection results. [Background technology]

[0002] Photodetectors for the spectrally selective detection of electromagnetic radiation are used for the qualitative and quantitative detection of electromagnetic radiation of a specific wavelength (hereinafter also referred to as "light") in the incident radiation. In this case, the incident radiation is a broadband radiation including many different wavelengths of light. Such photodetectors often contain a filter or an optical cavity, which allows the resonance of only a specific wavelength of the incident radiation inside the cavity. Here, the optical cavity is formed by mirror surfaces, at least one of which is semi-transparent and arranged at a distance L from each other. Inside the optical cavity, the radiation (electromagnetic wave) of the resonant wavelength is reflected and amplified many times between the mirror surfaces, and in so doing passes through the photoactive layer, where the electromagnetic radiation is converted into electrical power. Such photodetectors are described, for example, in WO2017 / 029223A1. Every resonant wave has a natural number of oscillation maxima in the optical cavity, and this is called a resonant wave of order i, where i corresponds to the number of oscillation maxima. All generated resonant waves of order 1 to order n contribute to the electrical signal of the photodetector, so that detection of specific wavelengths of the resonant waves is only possible to a limited extent for the wavelengths to be detected or only with great external effort, for example by upstream filters or complex evaluation of the measured electrical signal.

[0003] Another essential factor for the accuracy of detection of a particular wavelength in an optical cavity is the width of the wavelength range amplified by the optical cavity. The individual resonant wavelengths have been described above, and ideally only these individual resonant wavelengths form standing waves, but in reality, a certain wavelength range around each of these individual resonant wavelengths is amplified in the optical cavity and forms a standing wave. The amplification of the optical cavity, which determines the external quantum efficiency (EQE) of a given wavelength, is approximately a succession of super-Gaussian or Lorentzian distributions, with maxima at each resonant wavelength. The resonant wavelengths can be recognized as peaks when plotted spectroscopically, i.e., in a representation of the magnitude of the amplification of the photodetector against the wavelength. The width of the wavelength range in which the peak exists and in which the amplification reaches half of its maximum at its range limit is called the peak width. The wider this peak width, the less accurate the detection, since the wavelengths in the amplified wavelength range can no longer be distinguished from one another. This is represented by the cavity quality Q, which is approximately calculated as the quotient of the peak wavelength and the peak width. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2017 / 029223A1 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a photodetector for the spectrally selective detection of electromagnetic radiation by means of an optical cavity, which allows for improved detection. Furthermore, it is an aim to provide a space-saving structure of the photodetector for the detection of electromagnetic radiation of a number of different wavelengths, which allows for a miniaturized detector or spectrometer. [Means for solving the problem]

[0006] This problem is solved by a photodetector according to one of the independent claims. Advantageous developments and embodiments are contained in the dependent claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] A photodetector for the spectrally selective detection of electromagnetic radiation according to a first aspect of the invention comprises a first optoelectronic device for the detection of a first wavelength of electromagnetic radiation. In this case, it is possible to detect only the presence or absence of the first wavelength in the electromagnetic radiation incident on the photodetector (qualitative information) and / or the intensity of the radiation of the first wavelength in the incident electromagnetic radiation (quantitative information). The first optoelectronic device comprises a first optical cavity and at least one detection cell arranged in said first optical cavity. The first optical cavity is formed by two parallel mirror layers separated from each other. In all optical cavities of the present application, the distance between the two mirror layers is referred to as the physical length of the optical cavity, which is also referred to in the following for short as the length of the optical cavity. The length of the first optical cavity is designed such that, for the first wavelength, a resonant wave of order i belonging to it is formed in the first optical cavity. In this case, the following relationship generally applies for the relationship between the wavelength of the incident radiation fulfilling the resonance criterion and the physical length of the optical cavity:

[0008]

number

[0009] In the following description, unless otherwise specified, the term "resonant wave" refers to a resonant wave belonging to a wavelength to be detected in each optoelectronic device.

[0010] Each detection cell arranged in the first optical cavity comprises a photoactive layer. The photoactive layer preferably extends over the entire cross section of the first optical cavity, the cross section extending perpendicularly to the length of the first optical cavity. The photoactive layers of the detection cells are then respectively arranged in the first optical cavity such that exactly one oscillation maximum of the resonant wave is located in the photoactive layer. In other words, depending on which order the resonant wave formed by the first wavelength to be detected has, the photoactive layer is arranged in the optical cavity. In this case, preferably, the position of the oscillation maximum, i.e. the position of the intensity maximum of the electromagnetic field of the resonant wave, is located as centrally as possible in the photoactive layer, based on the thickness of the photoactive layer measured in the direction of the length of the first optical cavity. In this case, the layer thickness of the photoactive layer is adapted such that the node of the resonant wave adjacent to the oscillation maximum in the photoactive layer is no longer present in the photoactive layer.

[0011] In the present invention, the order of the resonant wave of the first optoelectronic device is higher than 1. In other words, in the first optoelectronic device, a first wavelength is detected which forms a resonant wave of order 2, 3, 4 or higher in the first optical cavity, because the photoactive layer is located in exactly one vibration maximum of this resonant wave.

[0012] The higher order resonant waves have a significantly narrower peak width than the first order resonant wave detected by the prior art, and therefore a more precise differentiation of different wavelengths, i.e., a better spectral resolution of the photodetector, can be achieved.

[0013] Preferably, at least one of the detection cells comprises a first charge transport layer and a second charge transport layer, with the photoactive layer being arranged between said first and second charge transport layers. The individual layers are arranged one above the other along the length of the first optical cavity. The first and second charge transport layers also preferably extend over the entire cross section of the first optical cavity, with the first charge transport layer contacting a first surface of the photoactive layer and the second charge transport layer contacting a second surface of the photoactive layer, said second surface being opposite said first surface. The charge transport layers serve to extract the charge from the photoactive layer and to conduct it to electrical contacts (also called electrodes), which transmit the electrical signals generated in the detection cells to an evaluation unit suitable for their evaluation. These charge transport layers are particularly advantageous in the case of very thin photoactive layers having a thickness of less than 10 nm, and in this case are formed with a thickness of 10 nm or more. In the case of thicker photoactive layers, the charge transport layers can be made only very thin, for example in the range of 1 nm to 5 nm, and therefore they can also be called injection or extraction layers. In both cases, the charge transport layers are not necessarily always doped layers.

[0014] The mirror layers can be formed as highly reflective metal layers, for example made of silver (Ag) or gold (Au), semi-transparent mixed metal layers, for example made of Ag:Ca, or as dielectric mirrors (DBR - distributed Bragg reflector). In this case, at least one of the mirror layers can be semi-transparent in order to let the incident light into the optical cavity, while the other mirror layers can be opaque. This property can be adjusted, for example, via the thickness of the mirror layer and / or the material and mixture ratio of the components of the mirror layer, which is known to the person skilled in the art. If the mirror layers are made of materials with good electrical conductivity, for example conductive oxides, conductive organic compounds or metals, the mirror layers can serve as electrodes for sending the electrical signals generated in the detection cell to an evaluation unit suitable for evaluating them. The evaluation unit is not necessarily part of the photodetector, but can be fixedly connected to it and can be formed on or in the same base on which the photodetector is formed. In the case of a dielectric mirror, a thin layer of a material with good electrical conductivity, for example a thin metal layer, can be applied to the last dielectric layer of the mirror layer facing the detector cell, so that in this case too the mirror layer can function as an electrode. Further possibilities for electrical contacting of the detector cell will be explained later.

[0015] As the photoactive layer, in particular, 800 nm≦λ iFor detection of wavelengths in the near infrared (NIR) range of ≦10 μm, the following materials come into consideration: fullerenes, for example C60 or C70, mixed with donors such as materials from the following substance groups: phthalocyanines (for example zinc phthalocyanine or iron phthalocyanine), pyrans, for example bispyranylidene (also abbreviated as TPDP), fulvalenes, for example tetrathiofulvalene (also called OMTTF), as well as aromatic amines (for example N,N,N',N'-tetrakis(4-methoxyphenyl)benzidines (also called MeO-TPD), 2,7-bis[N,N-bis(4-methoxy-phenyl)amino]9,9-spiro-bifluorene (spiro- MeO-TPD) or 4,4',4''-tris(3-methylphenyl-phenylamino)triphenylamine (also abbreviated m-MTDATA), bisthiopyranylidenes, bipyridinylidenes or diketopyrrolopyrroles. Substances such as HatCN:BFDPB, HATCN:4P-TPD, HATCN:a-NPB would also be possible. Of course, any other photoactive material could be considered, for example polymers produced using liquid processing, for example polymers from the substance group of pyrithiophenes (for example poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophenes (also abbreviated pBTTT).

[0016] In this case, the photoactive layers preferably have a thickness in the range of 0.1 nm to 1 μm, depending on the material of the photoactive layer as well as on the overall structure of the optoelectronic device. Particularly preferably, the thickness of the photoactive layer for charge transport photodiodes (CTPDs) utilizing direct interchromophore charge transport states, for example with C60:TPDP, is in the range of 10 nm to 1000 nm, whereas for photodiodes utilizing direct material absorption and separating the charge carriers in a bulk- or flat heterojunction (BHJ, FHJ), for example with C60:ZnPc, it is in the range of 0.1 nm to 100 nm.

[0017] Examples of the charge transport layer include aromatic amines (e.g., N,N,N',N'-tetrakis(4-methoxyphenyl)benzidines (also abbreviated as MeO-TPD) or 2,7-bis[N,N-bis(4-methoxyphenyl)amino]9,9-spirodifluorenes (also abbreviated as spiro-MeO-TPD) or N4,N4'-bis(9,9-dimethyl-9H-fluoren-2-yl)-N4,N4'-diphenylbiphenyl-4,4'-diamines (also abbreviated as BF-DPB) or 9,9-bis[4-(N,N-bis-biphenyl-4-yl-amino)phenyl]-9H-fluorene (also abbreviated as BPAPF) or Po-3,4-ethylenediamines (e.g., ethylenediamines ... Polymers such as dioxythiophene poly(styrenesulfonate) (also abbreviated as PEDOT:PSS), spiro-TTB, NDP9, F6-TCNNQ, C60F48, BPhen, C60, HatnaCl6, MH250, W2(hpp)4, Cr2(hpp)4, NDN26 can be used. Of course, other suitable materials or combinations of at least two of the above materials can also be used. In this case, the material of the first charge transport layer and the material of the second charge transport layer of the detection cell differ in that one material is an electron conducting material and the other is a hole conducting material. The material of the charge transport layer can be a doped material, but does not have to be.

[0018] The electrical conductivity of the charge transport layer is preferably 10 -5 The thickness of the charge carrier transport layer is preferably in the range of 1 nm to 100 nm, where the thickness is generally smaller the greater the number of detector cells in the first optical cavity. Furthermore, the thickness of the first charge transport layer of the detector cell may be different from the thickness of the second charge transport layer of the detector cell.

[0019] When different detection cells are present in the first optical cavity, the photoactive layers and, if present, the first charge transport layer and the second charge transport layer of these different detection cells may differ from each other in terms of material and thickness.

[0020] Of course, in each case the sum of the thicknesses of all layers present in the first optical cavity, i.e. the photoactive layer(s), optionally the charge transport layer(s) and / or further layers, is the same as the length of the first optical cavity.

[0021] In one embodiment, the number of detector cells arranged in the first optical cavity corresponds to the order of the resonant wave, i.e. if a first wavelength belonging to a resonant wave of order 2 is to be detected, the first optoelectronic device comprises exactly two detector cells, whose photoactive layers are respectively arranged in exactly one and different vibration maximum of a resonant wave; if a first wavelength belonging to a resonant wave of order 3 is to be detected, the first optoelectronic device comprises exactly three detector cells, etc. In this case, the detector cells are respectively arranged one above the other along the length of the first optical cavity, and do not necessarily have to be adjacent to each other.

[0022] Alternatively, a number of detector cells less than the number of orders of the resonant wave can be arranged in the first optical cavity. For example, in principle, to detect a resonant wave of 2, 3 or more orders, one detector cell is sufficient, whose photoactive layer is optically arranged inside the cavity such that there is exactly one oscillation maximum of the resonant wave. This simplifies the manufacture of the photodetector and reduces the manufacturing costs by using simple and inexpensive materials instead of unformed detector cells.

[0023] Preferably, in the first optical cavity, at least one optically absorbing intermediate layer is arranged such that exactly one vibration node of the resonant wave is present in this optically absorbing intermediate layer. In optoelectronic devices designed for the detection of resonant waves of orders greater than order 2, preferably a plurality of optically absorbing intermediate layers are arranged such that each vibration node of the resonant wave is present in exactly one optically absorbing intermediate layer. The at least one optically absorbing intermediate layer serves to absorb resonant waves of orders different from the resonant wave belonging to the first wavelength. In particular, resonant waves adjacent to the resonant wave belonging to the first wavelength are annihilated at the nodes, while the resonant wave belonging to the first wavelength is hardly affected. Therefore, the attribution of the detected electrical signal to the first wavelength can be guaranteed for a wider range of first wavelengths and the usability of such photodetectors can be expanded.

[0024] In an embodiment, at least one of the optically absorbing intermediate layers is in direct contact with a detector cell, i.e. in direct contact with the photoactive layer or, if present, with one of the charge transport layers of this detector cell, and is made of an electrically conductive material. Furthermore, it is suitable for electrically conductive connection with an evaluation unit suitable for evaluating the electrical signal generated by at least one detector cell of the first optoelectronic device. Thus, such an intermediate layer serves as an electrical contact for drawing off the electrical signal from the detector cell, even if the photoactive layer or, if present, the corresponding charge transport layer of the associated detector cell is not in direct contact with the electrically conductive mirror layer.

[0025] In yet another embodiment, at least one optically transparent contact layer is arranged in the first optical cavity, which is directly in contact with the detector cell, i.e. directly with the photoactive layer of the detector cell or with one of the charge transport layers, if present, and is made of an electrically conductive material. This contact layer is suitable for electrically conductive connection with an evaluation unit suitable for evaluating the electrical signal generated by at least one detector cell of the first optoelectronic device. It therefore serves as an electrical contact for drawing off the electrical signal from the detector cell, even if the photoactive layer of the relevant detector cell or the corresponding charge transport layer, if present, is not in direct contact with the electrically conductive mirror layer or the electrically conductive intermediate layer. In this case, it is optically transparent, in particular for the resonant wavelength belonging to the first wavelength.

[0026] As materials for the optically absorbing intermediate layer, organic small molecules, organic mixed layers or polymers can be used, for example layers made of highly doped hole conducting materials, for example MeO-TPD:F6TCNNQ or PEDOT:PSS with quantum dots (QDs). If the optically absorbing intermediate layer is to be electrically conductive, metals, for example Ag or metal mixtures, for example Ag:Ca, or conductive oxides, for example indium tin oxide (ITO) or zinc oxide (ZnO) or aluminum doped zinc oxide (AZO) can also be used. The optically transparent contact layers can also be made of the same material. In this case, the optical and electrical properties of such intermediate or contact layers can be adjusted via the thickness and material mixture. The thicknesses of these layers are preferably in the range of 0.1 nm to 40 nm, more preferably in the range of 5 nm to 10 nm, in the case of metals, and on the other hand in the range of 20 nm to 100 nm, more preferably in the range of 30 nm to 60 nm, where in each case a low thickness is accompanied by a high optical transparency.

[0027] In the sense of the present invention, an optically absorbing layer used as an optically absorbing intermediate layer is understood to mean a layer suitable for absorbing a large amount of the energy of a specific electromagnetic wave so that it is dissipated. Such a specific electromagnetic wave has a wavelength different from the resonant wavelength belonging to a first wavelength. For this purpose, the material of the optically absorbing layer can be absorbing only for wavelengths different from the resonant wavelength belonging to the first wavelength, while it is not absorbing for the resonant wavelength belonging to the first wavelength. However, such a specific wavelength dependence of the absorption coefficient is not sufficient for adjacent resonant wavelengths in most materials, so that the selection of the absorbed wavelength is also performed by the spatial arrangement of the absorbing layer inside the optical cavity, as described above. Since it is generally true that the absorbance for an electromagnetic wave depends on the product of the absorption coefficient k of the material at a specific wavelength of the electromagnetic wave and the thickness d of the layer as well as the energy E of the electromagnetic wave in the layer area, this product for wavelengths that do not correspond to the resonant wavelength belonging to the first wavelength has a value of 1·E or more in the present invention (k·d·E≧1·E). Thereby, in order to achieve the disappearance of a specific electromagnetic wave, layers made of materials with a very large absorption coefficient k can be made very thin, whereas layers made of materials with a relatively low absorption coefficient k must be made correspondingly thicker. In contrast, in the sense of the present application, an optically transparent layer, for example used as a spacer layer or as an optically transparent contact layer, is understood to mean a layer that absorbs as little energy as possible of a specific electromagnetic wave and thus barely affects this wave or at least affects it to a lesser extent than the photoactive layer. Here, said specific electromagnetic wave is an electromagnetic wave with a resonant wavelength belonging to a first wavelength. For this, the product of the absorption coefficient k of the material at the wavelength of the specific electromagnetic wave, the thickness d of the layer as well as the energy E of the specific electromagnetic wave in the region of this layer has a value less than 1 (k·d·E<1·E). Thereby, in order to keep the influence of the specific electromagnetic wave small, layers made of materials with a very small absorption coefficient k can be made relatively thick, whereas layers made of materials with a relatively large absorption coefficient k must be made correspondingly thinner.Typical absorption coefficients for metals are, for example, in the range of greater than 0.5, whereas typical materials for the photoactive layer have absorption coefficients less than 0.01, and typical materials for the charge transport layer have absorption coefficients less than 0.1.

[0028] If the electrical contact of the detection cell to the evaluation unit is established via such an intermediate or contact layer, the mirror layer, which is now no longer necessary for the electrical contact, can be optimized with respect to its optical properties, i.e. reflective or semi-transmissive properties. By separating the optical and electrical elements of the optoelectronic device, an improvement of the detection result is possible via an improvement of the optical properties of the mirror layer.

[0029] In another embodiment, the first optoelectronic device has at least one external contact, which is in contact with the outer surface of the detector cell, i.e. with the outer surface of the photoactive layer or of one of the charge transport layers, if present, and is made of an electrically conductive material. This external contact is suitable for electrically conductive connection with an evaluation unit suitable for evaluating the electrical signal generated by at least one detector cell of the first optoelectronic device. Such an external contact therefore serves as an electrical contact for drawing off the electrical signal from the associated detector cell, even if the photoactive layer or, if present, the charge transport layer of this detector cell is not in direct contact with the electrically conductive mirror layer or the electrically conductive intermediate layer or the contact layer. As materials for such external contacts, in particular metals, such as Ag or Au, are used.

[0030] Preferably, the first optoelectronic device has at least two such external contacts, which are arranged on opposite sides of the detector cell, which are corresponding sides of the detector cell separated along the length of the optical cavity, i.e., for example, a first side of the photoactive layer on the side of the first mirror layer and a second side of the photoactive layer on the side of the second mirror layer, or a first charge transport layer and a second charge transport layer. Of course, in both cases, there must be an electrical separation between both external contacts. Thereby, an external contact directly on the photoactive layer can be used for thicker photoactive layers rather than very thin ones. In an embodiment with two external contacts per detector cell, no additional electrically conductive layer is present in this detector cell that can optically influence the resonant wave, and at the same time, the layers present in the optical cavity can be optimized for their optical properties, since the electrical contacts of the detector cell are decoupled from the mirror layers. Thereby, a further improvement of the detection result via an improvement of the cavity quality is possible.

[0031] In one optoelectronic device, the above-mentioned means for electrical contact can also be used in one detector cell or for different detector cells.

[0032] In an embodiment of the photodetector, at least one optically transparent spacer layer is arranged in the first optical cavity, the spacer layer being arranged between one of the mirror layers and the detector cell adjacent to the mirror layer, the optically transparent spacer layer being a layer that, as described above, has little effect on standing waves having a resonant wavelength belonging to at least the first wavelength, the material and the thickness of the spacer layer being selected according to the above conditions, the thickness also depending on the thickness of the other layers present in the optical cavity and on the length of the optical cavity.

[0033] When more than one detection cell is disposed in the first optical cavity, in an embodiment of the photodetector according to the invention, an optically transparent spacer layer of the type described above is disposed along the length of the first optical cavity between two detection cells disposed one above the other within the first optical cavity.

[0034] In this case, the optically transparent spacer layers are preferably electrically non-conductive, i.e. electrically insulating, and are preferably made of transparent oxides, such as Al2O3, SiO2, TiO2, or organic compounds, such as are also used for the charge transport layers. In this case, these layers are preferably made of 10 -6 / cm 2 / Vs and therefore has a very low electrical conductivity. In this case, the electrical contact of the charge transport layer of the detection cell in contact with the spacer layer to the evaluation unit is established via an electrically conductive intermediate layer or contact layer or an external contact, as described above. Therefore, the mirror layer, which is no longer necessary for electrical contact, as well as the remaining layers in the optical cavity, can be optimized independently of each other with respect to their optical or electrical properties. By separating the optical and electrical elements of the photodetector, an improvement of the detection result is possible.

[0035] In an embodiment, the photodetector comprises a second optoelectronic device for the detection of a second wavelength of electromagnetic radiation. The second optoelectronic device, like the first optoelectronic device, comprises a second optical cavity and at least one detector cell arranged in the second optical cavity. The second optical cavity is also formed by two parallel mirror layers spaced apart from each other, the length of the second optical cavity being designed such that a resonant wave of order j associated with the second wavelength forms in the second optical cavity. Each detector cell of the second optoelectronic device comprises a photoactive layer, the photoactive layer being arranged respectively within the second optical cavity such that one oscillation maximum of the resonant wave is in the photoactive layer. In such a photodetector, the length of the first optical cavity is different from the length of the second optical cavity and / or the order of the resonant wave associated with the second wavelength is different from the order of the resonant wave associated with the first wavelength. In this case, the order of the resonant wave of the second optoelectronic device can also be order 1. Preferably, at least one detector cell of the second optoelectronic device also comprises a first charge transport layer and a second charge transport layer between which the photoactive layer is disposed, i.e., said layers are disposed overlapping or abutting each other along the length of the second optical cavity.

[0036] In such a photodetector, the first and second optoelectronic devices can be arranged side by side along a direction perpendicular to the length of the first and second optical cavities. This arrangement is also called a lateral arrangement. In this case, they can be arranged at a distance from each other and physically isolated from each other, so that each optoelectronic device can be individually (separately) connected to an evaluation unit. The first and second optoelectronic devices can also be arranged in contact with each other, but this requires electrical separation of the charge transport layer (if present) and / or layers of the optoelectronic device that emit the electronic signal, such as mirror layers, intermediate layers or contact layers, i.e. pixelation of these layers. A given lateral arrangement of different optoelectronic devices can be repeated once or several times in parallel, i.e. arranged side by side, along a direction perpendicular to the length of the optical cavities. An image forming device, a so-called imager system, can thereby be realized.

[0037] In another embodiment of the photodetector comprising two optoelectronic devices, the first and second optoelectronic devices are arranged one on top of the other such that the length of the first optical cavity and the length of the second optical cavity run along a common line. This arrangement is also referred to as a vertical arrangement. In this case, the first and second optical cavities are connected to each other by a semi-transparent mirror layer, i.e. the first and second optical cavities share this semi-transparent mirror layer, which serves as a mirror in each of both optoelectronic devices, respectively. With this structure, which resembles a stack of optoelectronic devices, on the one hand, the active surface area of ​​the photodetector can be reduced. On the other hand, this structure allows a photodetector that is selectively responsive to a specific angle of incidence of the incident electromagnetic radiation, where an optoelectronic device with a long optical cavity length detects a defined wavelength or a defined wavelength range in the incident radiation at a large angle of incidence, and on the other hand, an optoelectronic device with a relatively short optical cavity length detects the same defined wavelength or the same defined wavelength range in the incident radiation at a small angle of incidence, where both optoelectronic devices are devices of the same order. Of course, the different response behavior of the angle dependence of both these optoelectronic devices can be achieved not only or only through the length of the optical cavity, but also or additionally through different orders of the optoelectronic devices.

[0038] A photodetector for the spectrally selective detection of electromagnetic radiation according to a second aspect of the invention comprises a first optoelectronic device for the detection of a first wavelength of electromagnetic radiation. In this case, it is possible to detect only the presence or absence of the first wavelength in the electromagnetic radiation incident on the photodetector (qualitative information) and / or the intensity of the radiation of the first wavelength in the incident electromagnetic radiation (quantitative information). The first optoelectronic device comprises a first optical cavity, a detector cell arranged in the first optical cavity, and at least one optically transparent spacer layer. This first optical cavity is formed by two parallel mirror layers spaced apart from each other, the length of the first optical cavity being designed such that for the first wavelength, a resonant wave of order i belonging to it forms in the first optical cavity. The formula (1) already mentioned above applies, where i can be 1 or more.

[0039] The detection cell arranged in the first optical cavity includes a photoactive layer, which preferably extends across the entire cross section of the first optical cavity, with the cross section extending perpendicular to the length of the first optical cavity, and the photoactive layer of the detection cell is arranged inside the first optical cavity such that the oscillation maximum of the resonant wave is in the photoactive layer, whereby the photoactive layer is preferably arranged in the center of the first optical cavity based on the length.

[0040] Preferably, the detection cell further comprises a first charge transport layer and a second charge transport layer, with the photoactive layer being arranged between said first and second charge transport layers. The individual layers are arranged one above the other along the length of the first optical cavity. The first and second charge transport layers also preferably extend over the entire cross section of the first optical cavity, with the first charge transport layer in contact with a first surface of the photoactive layer and the second charge transport layer in contact with a second surface of the photoactive layer, said second surface being opposite said first surface. The charge transport layers enhance the extraction of charges from the photoactive layer and their conduction to electrical contacts (also called electrodes), which transmit the electrical signals generated in the detection cell to an evaluation unit suitable for their evaluation. This charge transport layer can be made very thin, so that it can also be called an injection or extraction layer. It does not necessarily have to be a doped layer.

[0041] At least one optically transparent spacer layer is arranged between one of the mirror layers and the detector cell, i.e. between the associated mirror layer of this detector cell and the photoactive layer or between the associated mirror layer and the charge transport layer adjacent to this mirror layer. The optically transparent spacer layer is formed as described above with respect to its optical properties and is furthermore electrically insulating, so that electrical signals from the photoactive layer or the corresponding charge transport layer cannot be read out, i.e. sent to the evaluation unit, via the corresponding adjacent mirror layer.

[0042] Therefore, according to the present invention, the first optoelectronic device of the photodetector according to the second aspect comprises at least one external contact in contact with an outer surface of the detector cell, i.e. in contact with the photoactive layer or, if present, the charge transport layer, which is separated from the adjacent mirror layer by at least one spacer layer, said external contact being made of an electrically conductive material, for example a material as already mentioned for the photodetector according to the first aspect, and being suitable for electrically conductively connecting with an evaluation unit, said evaluation unit being suitable for evaluating a signal generated from the detector cell of the first optoelectronic device.

[0043] Since an electrically conductive contact layer extending over a large area of ​​the cross section of the first optical cavity is dispensed with and instead the electrical contacts are laid on the outer surface of the detection cell, the optical propagation of the resonant wave in the optical cavity is less disturbed, thereby improving the cavity quality of the first optical cavity. Furthermore, the layers arranged in the optical path of the resonant wave can be optimized with respect to their materials for their optical properties. All this contributes to improving the detection result.

[0044] In one preferred embodiment of the photodetector according to the second aspect, an optically transparent spacer layer as described above is disposed between any of the mirror layers and the detector cell, i.e. between the associated mirror layer of the detector cell and the photoactive layer or the charge transport layer adjacent to said mirror layer, and the first optoelectronic device has at least two external contacts, in each case said external contacts contacting the outer surface of the detector cell on a first side and on a second side, said first and second sides of the detector cell being opposite along the length of the optical cavity, whereby any external contacts contact the outer surface of the photoactive layer or the outer surface of the first or second charge transport layer (if present) on the first and second sides of the detector cell.

[0045] A photodetector for the spectrally selective detection of electromagnetic radiation according to a third inventive aspect comprises a first optoelectronic device for the detection of a first wavelength of electromagnetic radiation and a second optoelectronic device for the detection of a second wavelength of electronic radiation, again capable of detecting only the presence or absence of the first or second wavelength in the electromagnetic radiation incident on the photodetector (qualitative information) and / or what the intensity of radiation of the first or second wavelength in the incident electromagnetic radiation is (quantitative information).

[0046] The first optoelectronic device comprises a first optical cavity and at least one detector cell arranged in the first optical cavity, the first optical cavity being formed by two parallel mirror layers spaced apart from each other, the length of the first optical cavity being designed such that for a first wavelength a resonant wave of order i is formed in the first optical cavity, the equation (1) already mentioned above applies.

[0047] Any detector cell arranged in the first optical cavity comprises a photoactive layer, all as described for the photodetector according to the first aspect, with the photoactive layer of the detector cell being respectively arranged inside the first optical cavity such that exactly one oscillation maximum of a resonant wave of order i is present in the photoactive layer. Again, this corresponds to the first optoelectronic device according to the first aspect. However, unlike the photodetector according to the first aspect, the resonant wave can be a resonant wave of order 1, i.e. i≧1.

[0048] The second optoelectronic device comprises a second optical cavity and at least one detector cell arranged in the second optical cavity, the second optical cavity being formed by two parallel mirror layers spaced apart from each other, the length of the second optical cavity being designed such that for a first wavelength a resonant wave of order j is formed in the first optical cavity, the formula (1) already given above applies, with i replaced by j.

[0049] Any detector cell arranged in the second optical cavity includes a photoactive layer as already described for the first optoelectronic device, with the photoactive layer of the detector cell being arranged within the second optical cavity respectively such that exactly one oscillation maximum of a resonant wave of order j is located within the photoactive layer, again in accordance with the structure of the first optoelectronic device, again the resonant wave can be of order 1 or higher.

[0050] Preferably, at least one detection cell of the first and / or second optical cavity further comprises a first charge transport layer and a second charge transport layer as already described in relation to the photodetector according to the first aspect.

[0051] According to the invention, the length of the second optical cavity is different from the length of the first optical cavity and / or the order of the resonant wave belonging to the second wavelength is different from the order of the resonant wave belonging to the first wavelength. In this case, the resonant waves of both optoelectronic devices can also be resonant waves of order 1. Furthermore, according to the invention, the first and second optoelectronic devices are arranged one on top of the other such that the lengths of the first and second optical cavities run along a common line, wherein the first and second optical cavities are connected to each other by a semi-transparent mirror layer which is one of the mirror layers of the first optical cavity and the second optical cavity, respectively.

[0052] With this structure, which resembles a stack of optoelectronic devices, on the one hand, the active surface area of ​​the photodetector can be reduced. On the other hand, this structure allows the photodetector to selectively respond to a specific angle of incidence of the incident electromagnetic radiation, where an optoelectronic device with a long optical cavity length detects a defined wavelength in the incident radiation at a large angle of incidence, and on the other hand, an optoelectronic device with a relatively short optical cavity length detects the same defined wavelength in the incident radiation at a small angle of incidence, where both optoelectronic devices are of the same order. Of course, the different response behavior of the angle dependence of these two optoelectronic devices can be achieved not only or only through the length of the optical cavity, but also or additionally through different orders of the optoelectronic devices.

[0053] The semi-transparent mirror layer belonging to both optoelectronic devices is made of one or more of the materials already known in connection with the photodetector according to the first aspect, with the thickness of the material being adjusted with respect to the reflectivity at the first or second wavelength and the transmittance at the other of the first or second wavelengths. If the semi-transparent mirror layer serves as an electrical contact for reading out an electrical signal generated in at least one of the optoelectronic devices, this semi-transparent mirror layer is electrically conductive.

[0054] In an embodiment, the number of detection cells arranged in the first optical cavity and / or in the second optical cavity corresponds to the order of the respective resonant wave.

[0055] In one or both optoelectronic devices, an optically transparent and electrically conductive contact layer or spacer layer may be arranged between one of the mirror layers and the detector cell adjacent to this mirror layer, as described in connection with the first optoelectronic device of the photodetector according to the first aspect. If one of the optoelectronic devices is a device with more than one order, a respective optically transparent spacer layer may also be formed in the optical cavity of the optoelectronic device between two detector cells arranged one above the other along the length of the optical cavity, or one or more optically absorbing intermediate layers may be formed.

[0056] Furthermore, at least one of the detection cells of the first or second optoelectronic device can have at least one external contact in contact with an outer surface of the photoactive layer or an outer surface of one of the charge transport layers, made of an electrically conductive material and suitable for electrically conductive connection with an evaluation unit, the evaluation unit being suitable for evaluating an electrical signal generated by the detection cell. Again, the order of the resonant wave in the corresponding optoelectronic device is not important.

[0057] Of course, one or more further optoelectronic devices can also be stacked on top of the first and second optoelectronic devices, in which case one semi-transparent mirror layer each is arranged between adjacent optoelectronic devices and belongs to both adjacent devices.

[0058] The materials of the individual layers of the optoelectronic device of a photodetector according to the second or third aspect of the present invention are similar to the materials described in relation to the layers of the optoelectronic device of a photodetector according to the first aspect of the present invention.

[0059] A photodetector according to any aspect of the invention may be formed on a substrate and may be surrounded by a housing or encapsulation as protection against environmental influences, but at least the substrate or housing must be transparent to incident electromagnetic radiation, thereby allowing the incident electromagnetic radiation to impinge on the photodetector.

[0060] Within the meaning of the present invention, the above-mentioned embodiments or individual features can be combined with one another to form optoelectronic devices and photodetectors, insofar as they do not exclude one another.

[0061] The invention will now be explained more clearly with the aid of examples and drawings, in which the dimensions of the individual elements and their relative relationships are not to scale but are merely shown diagrammatically, and the same reference symbols refer to corresponding components of the same type.

[0062] Unless otherwise stated, longitudinal sections are shown. [Brief description of the drawings]

[0063] [Figure 1A] FIG. 1A is a first embodiment of a photodetector according to the present invention according to a first aspect of the present invention, in which the optoelectronic device is an order 2 device and includes two detector cells. [Figure 1B]FIG. 1B is a second embodiment of a photodetector according to the first aspect of the present invention, in which the optoelectronic device is an order 2 device and includes one detector cell. [Figure 1C] FIG. 1C is a third embodiment of a photodetector according to the first aspect of the present invention, in which the optoelectronic device is an order 3 device and includes three detector cells. [Diagram 2] FIG. 2 is a fourth embodiment of a photodetector according to the first aspect of the invention, in which the optoelectronic device is an order 2 device and includes an optically absorbing intermediate layer. [Diagram 3] FIG. 3 is a fifth embodiment of a photodetector according to the present invention in accordance with the first aspect of the present invention, wherein the optoelectronic device is an order 2 device and includes a spacer layer and an optically transparent and electrically conductive contact layer. [Figure 4A] FIG. 4A is a sixth embodiment of a photodetector according to the first aspect of the present invention, in which the optoelectronic device is an order 2 device and includes a spacer layer as well as external electrical contacts. [Figure 4B] FIG. 4B is a cross-sectional top view of the photodetector of FIG. 4A taken along line AA'. [Figure 5A] FIG. 5A is a seventh embodiment of a photodetector according to the first aspect of the present invention, the photodetector including two optoelectronic devices arranged side-by-side. [Figure 5B] FIG. 5B is an eighth embodiment of a photodetector according to the first aspect of the present invention, the photodetector including two optoelectronic devices arranged one on top of the other. [Figure 6A] FIG. 6A is a first embodiment of a photodetector according to the second aspect of the present invention, in which the optoelectronic device is an order-1 device and includes external electrical contacts as well as an optically absorbing spacer layer. [Figure 6B] FIG. 6B is a second embodiment of a photodetector according to the present invention in accordance with a second aspect of the present invention, where the detection cell includes a charge transport layer. [Figure 7]FIG. 7 shows an embodiment of a photodetector according to the third aspect of the present invention, the photodetector comprising two optoelectronic devices of order 1 arranged one on top of the other.

[0064] 1A to 5B show various embodiments of a photodetector according to a first aspect of the invention. In all embodiments according to the first aspect, the invention is characterized in that at least one optoelectronic device is an order 2 or higher device.

[0065] FIG. 1A shows a first embodiment 1 of a photodetector according to the invention according to a first aspect of the invention. The photodetector 1 comprises an optoelectronic device 100, which is arranged between a transparent first substrate 201, for example made of glass or transparent plastic, and a second substrate 202. This second substrate 202 can likewise be transparent, but can also be made opaque, semi-transparent or reflective, and can be an encapsulation made of glass, metal or plastic, for example. In this case, the optical properties of the first and second substrates 201, 202 relate to the radiation having a first wavelength to be detected in the photodetector 1. Incident radiation 301, which may comprise a broad spectrum, for example UV light to infrared wavelengths, i.e. in the wavelength range of 100 nm to 50 μm, or may comprise only different wavelengths in one spectral range, for example the infrared range of 780 to 50 μm, or only one wavelength in one of these ranges, enters the photodetector 1 from a radiation source 300. The incident radiation 301 can be, for example, radiation that has passed through a medium, for example a liquid, or radiation that has been reflected by a medium, for example by a solid, or radiation that is generated directly by a radiation source 300. The incident radiation 301 can enter the optoelectronic device 100 through the first substrate 201, as shown in Figure 1A, but can also enter the optoelectronic device 100 through the second substrate 202, if the second substrate 202 is correspondingly formed.

[0066] The optoelectronic device 100 comprises a semi-transparent first mirror layer 11 arranged on a first substrate 201, and a second mirror layer 12 which is fully reflective and arranged on a second substrate 202. Both mirror layers 11, 12 are made of, for example, silver (Ag), where the first mirror layer 11 has a smaller thickness, for example 27 nm, than the second mirror layer 12 which has a thickness of, for example 100 nm. The first mirror layer 11 and the second mirror layer 12 are arranged parallel to each other with a distance L therebetween, thus forming an optical cavity between them. The length of the optical cavity, i.e. the distance L, as well as the thicknesses of the individual layers of the optoelectronic device 100, are measured perpendicular to the parallel planes of the mirror layers 11 and 12, respectively. For a particular first wavelength of incident radiation 301, standing resonant waves of different orders and corresponding resonant wavelengths form in the optical cavity according to the previously described equation (1). For example, a resonant wave 13 of order 2 is shown in FIG. 1A, whose wavelength is related to a first wavelength to be detected in the photodetector 1 through the effective refractive index of the layers present in the optical cavity and the path of the radiation, such as the first substrate 201 and the first mirror layer 11. In the optical cavity, i.e. between the mirror layers 11 and 12, two detection cells 21 and 22 for detecting the resonant wave are arranged. Each detection cell 21, 22 comprises a photoactive layer 210 or 220, which is bordered on one side of the length of the optical cavity by a first charge transport layer 211 or 221, respectively, and on the other side of the length of the optical cavity by a second charge transport layer 212 or 222, respectively. The first charge transport layer 221 or 221 is, for example, a hole-conducting material, while the second charge transport layer 212 or 222 is an electron-conducting material. The photoactive layers 210, 220 are made of, for example, TPDP:C60 and have a thickness of 100 nm, and are arranged within the optical cavity such that exactly one intensity maximum (also called vibration antinode) of the resonant wave 13 is present within one of the photoactive layers 210, 220, respectively. The resonant wave 13 detected by the optoelectronic device 100 is a second order wave, and therefore the optoelectronic device 100 is referred to as a second order device.

[0067] The first charge transport layer 211 of the first detector cell 21 contacts the second mirror layer 12, and the second charge transport layer 222 of the second detector cell 22 contacts the first mirror layer 11. Furthermore, the second charge transport layer 212 of the first detector cell 21 and the first charge transport layer 221 of the second detector cell 22 are adjacent to each other. An electrical signal generated in the detector cells 21 and 22 is transmitted through the mirror layers 11 and 22, which are electrically conductive and electrically conductively connected to an evaluation unit, which is suitable for generating qualitative and / or quantitative information about the radiation of the first wavelength contained in the incident radiation 301 from the electrical signal.

[0068] The concept of order of optoelectronic devices is further explained with reference to Figures 1B and 1C. The depiction of the substrate and the radiation source is omitted in most of the following figures.

[0069] Figure 1B shows an optoelectronic device 101 of a second embodiment 2 of a photodetector according to the first aspect of the invention. In contrast to the optoelectronic device 100 of Figure 1A, only one detector cell 21 is arranged in the optical cavity of the optoelectronic device 101, formed as described with reference to Figure 1A. Instead of the second detector cell 22 of the optoelectronic device 100 of Figure 1A, in this case an optically absorbing and electrically conductive intermediate layer 30 and an optically transparent spacer layer 40 are arranged between the detector cell 21 and the first mirror layer 11. In this case too, the photoactive layer 210 of the detector cell 21 is arranged at exactly one intensity maximum of the resonant wave 13, which is again a resonant wave of order 2, while the intermediate layer 30 is arranged at the central node of the resonant wave 13. Since the intermediate layer 30 is made optically absorbing, all further resonant waves which would in principle be formed in the optical cavity between the mirror layers 11 and 12, whose vibration nodes are not present in the intermediate layer 30, disappear. Therefore, among others, the resonant waves of adjacent orders, namely the resonant waves of orders 1 and 3, disappear.

[0070] In the case shown in FIG. 1B, the spacer layer 40 is made of a non-conductive or poorly conductive material, for example Al2O3. The intermediate layer 30 therefore serves as a contact layer for transmitting the electrical signal generated in the detection cell 21 to the evaluation unit and for this purpose is made of an electrically conductive material, for example Ag:Ca, and is formed with a thickness of, for example, 6 nm, the intermediate layer 30 being electrically conductively connected to the evaluation unit. For this purpose, the intermediate layer 30 is formed in such a way that it protrudes from the lateral edges of the other layers in the optical cavity and can be connected with electrical wires to the evaluation unit, for example by means of clamps or other joining elements, for example bond wires. If the material of the spacer layer is electrically conductive, the intermediate layer can also be configured to be light-absorbing and weakly conductive. Furthermore, if the effect of disappearance of other resonant waves is not desired, the intermediate layer can also be omitted completely. Similarly, in other embodiments, the intermediate layer is configured to be non-absorbing but electrically conductive, thereby allowing electrical connection of the detection cell 21 to the evaluation unit via the intermediate layer, but without dissipating the resonant wave.

[0071] Although the optoelectronic device 101 only has one detection cell 21, the optoelectronic device 101 is also an order 2 device because it detects and evaluates an order 2 resonant wave.

[0072] 1C shows an optoelectronic device 102 of a third embodiment 3 of a photodetector according to the first aspect of the invention. Here, a resonant wave 14 of order 3 is detected, so that the optoelectronic device 102 is an order 3 device. The optoelectronic device 102 comprises three detector cells 21-23, each comprising a photoactive layer 210, 220 or 230, and two charge transport layers 211 and 212 or 221 and 222 or 231 and 232, and arranged one above the other in an optical cavity. In this case, the photoactive layers 210, 220 and 230 are arranged in the optical cavity such that there is exactly one oscillation maximum of the resonant wave 14 in each of the photoactive layers 210, 220 or 230, respectively. Of course, the optoelectronic device 102 can also have only one or two detection cells, in which case it is still an order-three device, as long as the photoactive layer of each of the detection cells is located at exactly one vibration maximum of the resonant wave 14.

[0073] With reference to figures 2 to 4B further embodiments of the optoelectronic device of a photodetector according to the first aspect of the invention are described, in each case a device of order 2 is shown as an example. Thus, figure 2 shows an optoelectronic device 103 of a fourth embodiment 4 of the photodetector, which in this case has two detector cells 21 and 22. Between the detector cells 21 and 22 an intermediate layer 31 is arranged which is optically absorbing but not electrically conductive. However, the intermediate layer 31 may not interfere with the charge transport if the individual detector cells 21 and 22 are not individually electrically contacted to the outside, as shown in figure 2. In this case, the intermediate layer 31 is conductive for at least one charge transport, i.e. electrons or holes or for both. This can be achieved by making the intermediate layer 31 very thin. For example, the intermediate layer 31 can be made of a metal layer, for example Ag, or of a mixed metal layer, for example Ag:Ca, with a thickness in the range of 1 nm to 5 nm. The intermediate layer 31 can also be a very thin, highly doped and absorbing organic layer in the corresponding wavelength range of the resonant wave, for example made of BFDPB:NDP9 with a thickness of 1 nm. Alternatively, the intermediate layer 31 can be present as a structured layer and have holes that allow charge transport from one adjacent layer to another adjacent layer, while the area of ​​the intermediate layer 31 present leads to the disappearance of the resonant wave of the adjacent order. This intermediate layer 31 helps to disappear the resonant wave of the adjacent order (the order adjacent to the order of the resonant wave 13). To prevent the disappearance of the resonant wave 13, the intermediate layer 31 is arranged in the optical cavity at the position of the central vibration node of the resonant wave 13 and is made thin, for example only with a thickness in the range of 1 nm to 5 nm. The connection to the evaluation unit is established via the electrically conductive mirror layers 11 and 12, as in the case of the optoelectronic device 100 of FIG. 1A, but in other embodiments can be realized by different means.

[0074] In higher order optoelectronic devices configured to detect resonant waves of orders higher than order two, preferably multiple optically absorbing intermediate layers are formed, each arranged such that every vibration node of the resonant wave is located in exactly one optically absorbing intermediate layer.

[0075] 3 shows an optoelectronic device 104 of a fifth embodiment 5 of a photodetector, in which besides the detector cells 21 and 22 a spacer layer 40 and an electrically conductive and optically transparent contact layer 50 are arranged in the optical cavity of the optoelectronic device 104. The detector cells 21 and 22 are separated from each other and from the adjacent mirror layer 11 or 12, respectively, by the spacer layer 40. In this case, the spacer layer 40 is non-conductive or poorly conductive, so that electrical contact to the detector cells 21 and 22 via the mirror layer 11 or 12 is not possible, so that the electrical signals generated by the detector cells 21 and 22 are sent to the evaluation unit via the contact layer 50. For this purpose, the contact layer 50 is arranged adjacent to and between the first and second charge transport layers 211 and 212 or 221 and 222, respectively, and the spacer layer 40, and can be electrically conductively connected to the evaluation unit, respectively. In this case, the contact layers 50 are made flat, i.e. they are made over the entire lateral dimension of the charge transport layers 211, 212, 221 and 222, respectively. Since the contact layers 50 are arranged in a region of the optical cavity where the intensity of the resonant wave 13 does not include a node but has an intensity different from 0 (zero), the contact layers 50 must be made of an optically transparent material in order to avoid the disappearance of the resonant wave 13. The contact layers 50 can be made of, for example, PEDOT:PSS, ITO, ZnO or other conductive oxides and can each have a thickness of, for example, 10 nm to 40 nm. Again, as already explained with respect to the intermediate layer 30 in FIG. 1B, the contact layers 50 extend somewhat laterally from the other layers in the optical cavity in order to be able to realize an electrical connection to the evaluation unit.

[0076] Another possibility of electrical contact to the evaluation unit is shown for the optoelectronic device 105 of the sixth embodiment 6 of the photodetector in Figures 4A and 4B. In this case, the optoelectronic device 105 differs from the optoelectronic device 104 of Figure 3 in that there is no flat contact layer, but the electrical connection between the charge transport layers 211, 212, 221 and 222 is made via external electrical contacts 60, respectively. The external contacts 60 are made of an electrically conductive material, for example Ag, and contact at least a part of the outer surface of the charge transport layers 211, 212, 221 and 222. In this case, the outer surfaces of the charge transport layers 211, 212, 221 and 222 extend along the length of the optical cavity and are not in contact with other layers of the optoelectronic device 104 other than the external contacts 60. The external contacts 60 may overlap parts of the charge transport layers 211, 212, 221 and 222, i.e., may be in contact with the surfaces of the charge transport layers 211, 212, 221 and 222 that run parallel to the mirror layers 11, 12, or may extend into the charge transport layers 211, 212, 221 and 222. However, the external contacts 60 do not extend over the entire lateral dimensions of the charge transport layers 211, 212, 221 and 222. By recessing the external contacts in this way into the optical cavity, the active area of ​​the optoelectronic device, i.e., the area in which standing waves can occur, is restricted laterally, i.e., to a plane perpendicular to the length of the optical cavity. Furthermore, the external contacts may also serve as an optical aperture mask. Thereby, the external contacts 60 have little effect on the optical generation or propagation of the resonant wave 13. Preferably, the external contacts 60 surround the charge transport layers 211, 212, 221 and 222 along the entire periphery of their outer surfaces in a cross-section of the optoelectronic device, as shown in Figure 4B. Figure 4B shows a cross-section of the optoelectronic device 105 of Figure 4A along line A-A', where the external electrical contacts 60 form a frame around the first charge transport layer 211. Again, electrical connection elements or lines to an evaluation unit can be connected to the external electrical contacts 60 as already described with respect to Figure 1B.

[0077] Of course, other combinations of the optoelectronic device structures and layers depicted in Figures 1A-4B are possible, with optimization of the various layers for their optical and / or electrical properties, and optimization of the optoelectronic device for its detection properties and / or fabrication.

[0078] 5A and 5B, an embodiment of a photodetector according to a first aspect of the invention is described, where the photodetector comprises two optoelectronic devices each suitable for detection of different wavelengths in the incident radiation. Naturally, the number of optoelectronic devices can be increased arbitrarily and both embodiments can also be combined with each other.

[0079] 5A shows a seventh embodiment 7 of a photodetector with two optoelectronic devices 106 and 107, which are arranged side by side with each other, i.e. the optoelectronic devices 106 and 107 are arranged side by side with each other along a direction extending perpendicular to the length of the optical cavities of both devices 106 and 107. In the illustrated case, both devices 106 and 107 are arranged side by side with each other on a transparent first substrate 201 and are separated from the surroundings by a second substrate 202 in the form of a capsule. The first optoelectronic device 106 comprises a first mirror layer 11a, a second mirror layer 12a and two detector cells 21a and 22a, where a first optical cavity formed between said mirror layers 11a and 12a has a length L a The second optoelectronic device 107 has a first mirror layer 11b, a second mirror layer 12b, and two detector cells 21b and 22b, where a second optical cavity formed between the mirror layers 11b and 12b has a length L b In this case, in the illustrated case, L b <L aBoth optoelectronic devices 106 and 107 are devices of order 2, where, if the materials of the individual layers of the devices 106 and 107 are the same, the first optoelectronic device 106 can detect a first wavelength corresponding to the generated first resonant wave 13a and the second optoelectronic device 107 can detect a second wavelength corresponding to the generated second resonant wave 13b, where the first wavelength is greater than the second wavelength. However, these optoelectronic devices can also differ in terms of the order of the respective resonant waves, or in terms of the order of the respective resonant waves and in terms of the length of the optical cavities, in other embodiments, where the lengths of the optical cavities are the same. In the illustrated case, the first mirror layers 11a and 11b and the second mirror layers 12a and 12b serve to read out the electrical signals generated in the optoelectronic devices 106 and 107 and are for this purpose electrically conductively connected to an evaluation unit (not shown). In other embodiments, the electrical signal can also be sent to the evaluation unit via intermediate or contact layers or external contacts as illustrated with respect to Figures 1B and 3-4B, where the detection cells can be electrically isolated from one or both mirror layers of each device. In this case, the mirror layers of different photoactive devices that are electrically isolated from adjacent detection cells can also be formed jointly and connected to each other.

[0080] 5B shows an eighth embodiment 8 of a photodetector with two optoelectronic devices 108 and 109, which are arranged one on top of the other, i.e. the lengths of the first and second optical cavities of the optoelectronic devices 108 and 109 run along a common line, whereby the first and second optical cavities are connected to each other by a semi-transparent mirror layer. In other words, the optoelectronic devices 108 and 109 are stacked, so that the incident radiation reaches one of the optoelectronic devices only after it has passed through the other optoelectronic device. In the illustrated case, the incident radiation 301 enters the optoelectronic device 109 only after passing through the optoelectronic device 108.

[0081] The first optoelectronic device 108 comprises a semi-transparent mirror layer 11, a semi-transparent mirror layer 11' and two detector cells 21a and 22a, where a first optical cavity formed between the mirror layers 11 and 11' has a length L a The second optoelectronic device 109 comprises a semi-transparent mirror layer 11′, a second mirror layer 12 and two detector cells 21b and 22b, where a second optical cavity formed between the mirror layers 11′ and 12 has a length L b In this case, in the illustrated case, L b <L a However, L b >L a It is also possible that both optoelectronic devices 108 and 109 are order 2 devices, with the first optoelectronic device 108 being able to detect a first wavelength corresponding to the first resonant wave 13a created and the second optoelectronic device 109 being able to detect a second wavelength corresponding to the second resonant wave 13b created, with the first wavelength being greater than the second wavelength, if the materials of the individual layers of the devices 108 and 109 are the same. However, these optoelectronic devices can in other embodiments differ either with respect to the order of their respective resonant waves, or with respect to the order of their respective resonant waves and with respect to the length of their optical cavities, if the lengths of their optical cavities are the same.

[0082] Thereby, the eighth embodiment 8 of the photodetector can be used to conserve space while detecting two different wavelengths in the incident radiation 301. By stacking one or more further optoelectronic devices, more than two different wavelengths can be detected with a photodetector that only requires the lateral space of one optoelectronic device.

[0083] Moreover, by using this embodiment, a photodetector can be formed that is selectively responsive to the angle of incidence α of the incident radiation 301. In this case, for example, the optoelectronic device 108 will detect the presence of a first wavelength in the incident radiation 301 belonging to the wavelength of the first resonant wave 13a at a large angle of incidence α, while the optoelectronic device 109 will detect the presence of said first wavelength via detection of a second resonant wave 13b belonging to the first wavelength in the incident radiation 301 at a small angle of incidence α. In this case, the wavelengths of the first and second resonant waves 13a, 13b correspond to the first wavelength in the incident radiation 301 and the angle of incidence α.

[0084] In the illustrated case, the mirror layers 11, 11' and 12 serve for reading out the electrical signals generated in the optoelectronic devices 108 and 109 and are for this purpose electrically conductively connected to an evaluation unit (not shown). In other embodiments, the electrical signals can also be sent to the evaluation unit via intermediate or contact layers or external contacts as illustrated with respect to Figures 1B and 3-4B, whereby the detection cells can be electrically insulated from one or both mirror layers of the respective devices.

[0085] Of course, both embodiments described with respect to Figures 5A and 5B can be implemented in one photodetector, i.e., different optoelectronic devices can be arranged not only on top of each other, but also next to each other. Furthermore, these optoelectronic devices can also be formed according to one of the embodiments described with respect to Figures 1B and 2-4B, respectively, i.e., they can have spacer layers, optically absorbing intermediate layers, optically absorbing and electrically conductive intermediate layers, optically transparent and electrically conductive contact layers, and / or external electrical contacts, whereby the different optoelectronic devices can be configured in various ways.

[0086] Figure 6A shows a first embodiment 9 of a photodetector according to the invention according to a second aspect of the invention. According to the second aspect of the invention, this optoelectronic device can also have only one optoelectronic device of order 1. In Figure 6A, this is an optoelectronic device 110, which comprises a semi-transparent first mirror layer 11 and a second mirror layer 12, and a detector cell 21' in an optical cavity present between these mirror layers 11, 12. The detector cell 21' comprises a photoactive layer 210 but no charge transport layer. In this case, the photoactive layer 210 is arranged in the optical cavity such that the oscillation maximum of the resonant wave 15, which is a resonant wave of order 1, is in the photoactive layer 210. The photoactive layer 210 is separated from the mirror layer 11 or 12, respectively, by an optically transparent and electrically insulating spacer layer 40. The photoactive layer 210 can be connected to an evaluation unit via at least two external electrical contacts 60', similar to the external contacts 60 already described with reference to Figures 4A and 4B, so that the electrical signal generated in the detection cell 21 can be read. The external contacts 60' are made of an electrically conductive material, for example Ag, and are in contact with at least a part of the outer surface of the photoactive layer 210, which in this case extends along the length of the optical cavity and is not in contact with other layers of the optoelectronic device 110 other than the external contacts 60'. The external contacts 60' can either overlap a part of the photoactive layer 210, i.e. be in contact with the surface of the photoactive layer 210 that runs parallel to the mirror layers 11, 12, or extend into the photoactive layer 210. However, external contacts 60' do not extend across the entire lateral dimension of photoactive layer 210, but rather only a small portion, i.e., at most 10%, of the entire lateral dimension. Preferably, external contacts 60' surround the photoactive layer along the entire perimeter of the outer surface in a cross-section of the optoelectronic device, similar to that shown for external contacts 60 in FIG. 4B.In either case, one of the external contacts 60' is disposed on a first side of the photoactive layer 210 and the other of the external contacts 60' is disposed on a second side of the photoactive layer 210, the first and second sides being spaced apart and in opposing positions along the length of the optical cavity. In this case, the first side is near the first mirror layer 11, while the second side is near the second mirror layer 12. In this case, the photoactive layer 210 is made thick so that at least the external contact 60' on the first side of the photoactive layer 210 is electrically separated, i.e., insulated, from the external contact 60' on the second side of the photoactive layer 210. By separating the optical and electrical functions of the individual layers from each other, for example by separating the reflective function of the mirror layers 11, 12 from the electrical conductivity to the outside, all the components of the optoelectronic device 110 can be optimized either with respect to their optical properties or their electrical properties. By utilizing external contacts 60', optical losses in the optical cavity are further reduced, and therefore the detection quality and efficiency of the photodetector is further enhanced.

[0087] FIG. 6B shows a second embodiment 9' of a photodetector according to the invention according to the second aspect of the invention. The second embodiment 9' is made similarly to the first embodiment 9. However, the detector cell 21 of the optoelectronic device 110' comprises, in addition to the photoactive layer 210, a first charge transport layer 211 and a second charge transport layer 212, similar to the previously described detector cell of the photodetector according to the first aspect. The charge transport layers 211 and 212 are separated from their adjacent mirror layer 11 or 12, respectively, by an optically transparent and electrically insulating spacer layer 40. The charge transport layers 211 and 212 can be connected to an evaluation unit via external electrical contacts 60, as already explained with reference to FIGS. 4A and 4B, respectively, so that the electrical signal generated in the detector cell 21 can be read. The photoactive layer 210 in this embodiment can be made relatively thinner than in the first embodiment 9. Again, all components of the photoactive device 110' can be optimized either with respect to their optical properties or with respect to their electrical properties. By utilizing external contacts 60, optical losses in the optical cavity are further reduced, thus further enhancing the detection quality and efficiency of the photodetector.

[0088] FIG. 7 shows an embodiment 10 of a photodetector according to the invention according to a third aspect of the invention. According to this third aspect of the invention, the photoactive detector comprises two optoelectronic devices arranged one on top of the other, similar to the eighth embodiment 8 of the photodetector according to the first aspect of the invention, but in this case both optoelectronic devices can be devices of order 1. Accordingly, the photodetector 10 in the illustrated embodiment comprises two optoelectronic devices 111 and 112 arranged one on top of the other, whereby the lengths of the optical cavities of both devices 111 and 112 extend along a common line. The first optoelectronic device 111 comprises a semi-transparent mirror layer 11 and a semi-transparent mirror layer 11' as well as a detector cell 21a arranged therebetween, with the corresponding photoactive layer of the detector cell 21a being at the oscillation maximum of the resonant wave 15a, which is a resonant wave of order 1. The optical cavity of the optoelectronic device 111 then has a length L 1 , which corresponds to a first wavelength to be detected in the incident radiation. a The second optoelectronic device 112 has a semi-transparent mirror layer 11' and a mirror layer 12 and a detector cell 21b arranged therebetween, with the corresponding photoactive layer of the detector cell 21b being at an oscillation maximum of a resonant wave 15b, which is also a resonant wave of order 1. The optical cavity of the optoelectronic device 112 corresponds to a second wavelength to be detected among the incident wavelengths and has a length L a Length shorter than L b However, in other embodiments, L b L a It can be larger than .

[0089] As described with respect to FIG. 5B, the dependence of the wavelength of the resonant waves 15a, 15b on the angle of incidence of the incident radiation can also be utilized for angle-selective detection of particular wavelengths in the incident radiation.

[0090] Both optoelectronic devices 111 and 112 have in common a semi-transparent mirror layer 11'. In the illustrated embodiment, the mirror layers 11, 11' and 12 serve for reading out the electrical signals generated in the detection cells 21a and 21b and can be electrically conductively connected to an evaluation unit for that purpose. Of course, in other embodiments, other possibilities for establishing electrical contact to the charge transport layers of the detection cells can also be realised, for example optically transparent and electrically conductive contact layers or external electrical contacts as described above, and / or the detection cells can be separated from the neighbouring mirror layers by spacer layers.

[0091] Within the meaning of the present invention, the embodiments or individual features of the various aspects or embodiments described above can be combined with one another for the construction of a photodetector, if these are not mutually exclusive. EXAMPLES

[0092] In the following, various examples are described based on the above description and illustrations.

[0093] Example 1 is a photodetector for spectrally selective detection of electromagnetic radiation comprising a first optoelectronic device for detection of a first wavelength of electromagnetic radiation, a first optical cavity formed by two parallel mirror layers spaced apart from each other, the length of which is designed such that, for a first wavelength, a resonant wave of order i belonging to it is formed in the first optical cavity; and at least one detection cell arranged in said first optical cavity, each detection cell including a photoactive layer, each photoactive layer being arranged in the first optical cavity such that exactly one oscillation maximum of the resonant wave is present in the photoactive layer; Including, Here, the resonant wave order of the first optoelectronic device is greater than 1 and is a photodetector.

[0094] Example 2 is a photodetector according to Example 1, wherein at least one detection cell disposed within the first optical cavity further comprises a first charge transport layer and a second charge transport layer with a photoactive layer disposed therebetween, wherein the first charge transport layer, the photoactive layer and the second charge transport layer are disposed in a stacked manner along a length of the first optical cavity.

[0095] In Example 3, the photodetector according to Examples 1 or 2 can have detection cells arranged in the first optical cavity in a number that corresponds to an order of the resonant wave.

[0096] In Example 4, in a photodetector according to one of Examples 1 to 5, at least one optically absorbing intermediate layer is disposed within the first optical cavity, respectively, such that a vibration node of the resonant wave is within the absorbing intermediate layer.

[0097] In Example 5, in the photodetector according to Example 4, at least one of the at least one optically absorbing intermediate layers is in direct contact with at least one of the at least one detection cell, is made of an electrically conductive material and is suitable for electrically conductive connection with an evaluation unit suitable for evaluating an electrical signal generated from the at least one detection cell of the first optoelectronic device.

[0098] In Example 6, in a photodetector according to one of Examples 1 to 4, at least one optically transparent contact layer is arranged in the first optical cavity, which contact layer is in direct contact with one of the at least one detection cell, made of an electrically conductive material and suitable for electrically conductive connection to an evaluation unit suitable for evaluating an electrical signal generated from the at least one detection cell of the first optoelectronic device.

[0099] In Example 7, the first optoelectronic device of the photodetector according to one of Examples 1 to 4 has at least one external contact in contact with an outer surface of one of the at least one detection cell, made of an electrically conductive material, and suitable for electrically conductive connection to an evaluation unit suitable for evaluating an electrical signal generated from the at least one detection cell of the first optoelectronic device.

[0100] In Example 8, in a photodetector according to one of Examples 1 to 7, at least one optically transmissive spacer layer is disposed within the first optical cavity, the spacer layer being disposed between one of the mirror layers and a detection cell adjacent to the mirror layer.

[0101] In Example 9, in a photodetector according to one of Examples 1 to 8, at least two detection cells are disposed within the first optical cavity, and an optically transmissive spacer layer is disposed between the two detection cells that are overlappingly disposed within the first optical cavity along the length of the first optical cavity.

[0102] In Example 10, the photodetector according to any one of Examples 1-9 includes a second optoelectronic device for detection of a second wavelength of electromagnetic radiation, wherein the second optoelectronic device comprises: a second optical cavity formed by two parallel mirror layers spaced apart from each other, the length of the second optical cavity being designed such that a resonant wave of order j is formed in the second optical cavity for a second wavelength; and at least one detection cell disposed in the second optical cavity, each detection cell including a photoactive layer, each photoactive layer being disposed in the second optical cavity such that exactly one oscillation maximum of the resonant wave is present in the photoactive layer; has.

[0103] In this case, the length of the first optical cavity is different from the length of the second optical cavity and / or the order of the resonant wave belonging to the second wavelength is different from the order of the resonant wave belonging to the first wavelength.

[0104] In Example 11, in the photodetector according to Example 10, the first and second optoelectronic devices are arranged alongside one another along a direction perpendicular to the lengths of the first and second optical cavities.

[0105] In Example 12, in a photodetector according to Example 10, the first and second optoelectronic devices (108, 109) are arranged on top of each other such that the lengths of the first optical cavity and the second optical cavity extend along a common line, where the first and second optical cavities are connected to each other by a semi-transparent mirror layer.

[0106] Example 13 provides a photodetector for spectrally selective detection of electromagnetic radiation, comprising a first optoelectronic device for detection of a first wavelength of electromagnetic radiation, a first optical cavity formed by two parallel mirror layers spaced apart from one another, the length of which is designed such that a resonant wave of order 1 associated with a first wavelength is formed in the first optical cavity; - a detection cell disposed in the first optical cavity and including a photoactive layer, the photoactive layer being disposed in the first optical cavity such that an oscillation maximum of a resonant wave is present within the photoactive layer; and at least one optically transparent spacer layer disposed in the first optical cavity between one of the mirror layers and the detector cell; having In this case, the first optoelectronic device is a photodetector having at least one external contact that is in contact with an outer surface of the detection cell, is made of an electrically conductive material, and is suitable for electrically conductive connection to an evaluation unit that is suitable for evaluating an electrical signal generated from the detection cell of the first optoelectronic device.

[0107] In Example 14, the detection cell of the photodetector according to Example 13 disposed in the first optical cavity further comprises a first charge transport layer and a second charge transport layer with a photoactive layer disposed therebetween, wherein the first charge transport layer, the photoactive layer and the second charge transport layer are disposed in a stacked manner along the length of the first optical cavity.

[0108] In Example 15, in a photodetector according to one of Examples 13 or 14, two optically transparent spacer layers are arranged in the first optical cavity, a first of which is arranged between a first one of the mirror layers and a detector cell, and a second of which is arranged between a second one of the mirror layers and a detector cell. Furthermore, the first optoelectronic device of the photodetector according to Example 15 has at least two external contacts, where each one of the external contacts is in contact with an outer surface of the detector cell on a first side and on an outer surface of the detector cell on a second side, where the first and second sides of the detector cell are opposite each other along the length of the first optical cavity.

[0109] Example 16 is a first optoelectronic device for detection of a first wavelength of electromagnetic radiation, comprising: a first optical cavity formed by two parallel mirror layers spaced apart from each other, the length of which is designed such that, for a first wavelength, a resonant wave of order i belonging to it is formed in the first optical cavity; and at least one detection cell arranged in said first optical cavity, each detection cell including a photoactive layer, each photoactive layer being arranged in the first optical cavity such that exactly one oscillation maximum of the resonant wave is present in the photoactive layer; A first optoelectronic device comprising: and a second optoelectronic device for detecting a second wavelength of electromagnetic radiation, a second optical cavity formed by two parallel mirror layers spaced apart from each other, the length of the second optical cavity being designed such that a resonant wave of order j is formed in the second optical cavity for a second wavelength; and at least one detection cell disposed in the second optical cavity, each detection cell including a photoactive layer, each photoactive layer being disposed in the second optical cavity such that exactly one oscillation maximum of the resonant wave is present in the photoactive layer; a second optoelectronic device comprising: 1. A photodetector for spectrally selective detection of electromagnetic radiation, comprising: In this case, the length of the second optical cavity is different from the length of the first optical cavity and / or the order of the resonant wave belonging to the second wavelength is different from the order of the resonant wave belonging to the first wavelength, and the first and second optoelectronic devices are arranged one on top of the other such that the lengths of the first and second optical cavities extend along a common line, and the first and second optical cavities are connected to each other by a semi-transparent mirror layer, which is one of the mirror layers of the first optical cavity and the second optical cavity, respectively. It is a photodetector.

[0110] In Example 17, at least one detection cell of the photodetector according to Example 16, which is disposed in the first optical cavity or in the second optical cavity, further comprises a first charge transport layer and a second charge transport layer, with a photoactive layer disposed therebetween, wherein the first charge transport layer, the photoactive layer and the second charge transport layer are arranged in a stacked manner along the length of the first optical cavity or the second optical cavity.

[0111] In Example 18, the number of detection cells of the photodetector according to Example 16 or 17 arranged in the first optical cavity and / or in the second optical cavity corresponds to the order of the respective resonant wave.

[0112] [Explanation of symbols]

Table 1

Claims

1. A photodetector (1-8) for the spectrally selective detection of electromagnetic radiation, comprising a first optoelectronic device (100-106, 108) for the detection of a first wavelength of electromagnetic radiation, a first optical cavity formed by two parallel mirror layers (11, 11a, 11', 12, 12a) spaced apart from each other, with the length (L, L ａ ) is designed such that, for said first wavelength, a resonant wave (13, 13a, 14) of order i belonging thereto is formed in said first optical cavity; and at least one detection cell (21, 21a, 22, 22a, 23) arranged in said first optical cavity, each of said detection cells (21, 21a, 22, 22a, 23) comprising a photoactive layer (210, 220, 230), said photoactive layer (210, 220, 230) being arranged in said first optical cavity such that exactly one vibration maximum of said resonant wave (13, 13a, 14) is present in said photoactive layer (210, 220, 230), respectively; Including, wherein the order of the resonant wave (13, 13a, 14) of the first optoelectronic device (100-106, 108) is greater than 1; A photodetector (1-8), at least one optically absorbing intermediate layer (30, 31) is arranged in each of the first optical cavities such that a vibration node of the resonant wave (13, 13a, 14) is present in the optically absorbing intermediate layer (30, 31), whereby the optically absorbing intermediate layer (30, 31) is capable of absorbing the energy of a specific electromagnetic wave in the first optical cavity and dissipating the specific electromagnetic wave in the first optical cavity, whereby the specific electromagnetic wave in the first optical cavity has a wavelength different from the wavelength of the resonant wave belonging to the first wavelength, and / or the photodetector (1-8), characterized in that at least one optically transparent contact layer (50) is arranged in the first optical cavity, which contact layer (50) is in direct contact with one of the at least one detection cell (21, 21a, 22, 22a, 23), is made of an electrically conductive material and can be electrically conductively connected to an evaluation unit for evaluating an electrical signal originating from the at least one detection cell (21, 21a, 22, 22a, 23) of the first optoelectronic device (100-106, 108).

2. 2. The photodetector (1-8) of claim 1, characterized in that at least one of the detection cells (21, 21a, 22, 22a, 23) arranged in the first optical cavity further comprises a first charge transport layer (211, 221, 231) and a second charge transport layer (212, 222, 232) between which the photoactive layer (210, 220, 230) is arranged, wherein the first charge transport layer (211, 221, 231), the photoactive layer (210, 220, 230) and the second charge transport layer (212, 222, 232) are arranged in a stacked manner along the extension direction of the length of the first optical cavity.

3. 3. The optical detector (1-8) according to claim 1 or 2, wherein the number of detection cells (21, 21a, 22, 22a, 23) arranged in the first optical cavity corresponds to the order of the resonant wave (13, 13a, 14).

4. 4. The photodetector (1-8) according to claim 1, characterized in that the at least one optically absorbing intermediate layer (30, 31) is arranged in the first optical cavity and at least one of the at least one optically absorbing intermediate layer (30, 31) is in direct contact with one of the at least one detection cell (21, 21a, 22, 22a, 23), is made of an electrically conductive material and can be electrically conductively connected to an evaluation unit for evaluating an electrical signal generated by the at least one detection cell (21, 21a, 22, 22a, 23) of the first optoelectronic device (100-106, 108).

5. 5. The photodetector (1-8) according to claim 1, characterized in that the first optoelectronic device (100-106, 108) has at least one external contact (60), which is in contact with an outer surface of one of the at least one detection cell (21, 21a, 22, 22a, 23), is made of an electrically conductive material and can be electrically conductively connected to an evaluation unit for evaluating an electrical signal generated by the at least one detection cell (21, 21a, 22, 22a, 23) of the first optoelectronic device (100-106, 108).

6. 6. The photodetector (1-8) according to claim 1, wherein at least one optically transparent spacer layer (40) is arranged in the first optical cavity, the spacer layer (40) being arranged between one of the mirror layers (11, 11a, 11', 12, 12a) and the detection cell (21, 21a, 22, 22a, 23) adjacent to this mirror layer (11, 11a, 11', 12, 12a).

7. 7. A photodetector (1-8) according to claim 1, characterized in that at least two of the detection cells (21, 21a, 22, 22a, 23) are arranged in the first optical cavity and a further optically transparent spacer layer (40) is arranged between two of the detection cells (21, 21a, 22, 22a, 23) arranged one above the other in the first optical cavity along the extension of the length of the first optical cavity.

8. A photodetector (1-8) according to any one of claims 1 to 7, said photodetector (1-8) comprises a second optoelectronic device (107, 109) for detecting a second wavelength of said electromagnetic radiation, wherein said second optoelectronic device (107, 109) a second optical cavity formed by two parallel mirror layers (11b, 12b, 11', 12) spaced apart from one another, the length of which is designed such that for said second wavelength a resonant wave (13b) of order j belonging thereto is formed in said second optical cavity; and at least one detection cell (21b, 22b) arranged in the second optical cavity, where each of the detection cells (21b, 22b) comprises a photoactive layer (210, 220), where each of the photoactive layers (210, 220) is arranged in the second optical cavity such that exactly one vibration maximum of the resonant wave (13b) is present in the photoactive layer (210, 220); and - the length of the first optical cavity (L ａ ) is the length (L ｂ ) and / or the order of the resonant wave (13b) belonging to the second wavelength is different from the order of the resonant wave (13, 13a, 14) belonging to the first wavelength; The photodetector (1 to 8),

9. 9. The photodetector (1-8) according to claim 8, characterized in that the first optoelectronic device (100-106, 108) and the second optoelectronic device (107, 109) are arranged side by side along a direction perpendicular to the extension direction of the length (L a ) of the first optical cavity and to the extension direction of the length (L b ) of the second optical cavity.

10. 9. The photodetector (1-8) according to claim 8, characterized in that the first optoelectronic device (100-106, 108) and the second optoelectronic device (107, 109) are arranged one on top of the other such that the extension direction of the length (L a ) of the first optical cavity and the extension direction of the length (L b ) of the second optical cavity extend along a common line, and in that the first and second optical cavities are connected to each other by a semi-transparent mirror layer (11') which is one of the mirror layers (11 b, 12b, 11', 12).

11. A photodetector (9, 9') for the spectrally selective detection of electromagnetic radiation, comprising a first optoelectronic device (110, 110') for the detection of a first wavelength of electromagnetic radiation, a first optical cavity formed by two parallel mirror layers (11, 12) spaced apart from one another, the length of which is designed such that, for said first wavelength, a resonant wave (15) of order i belonging thereto is formed in said first optical cavity, said order of said resonant wave (15) being equal to or greater than 1; a detection cell (21, 21') arranged in said first optical cavity and comprising a photoactive layer (210), said photoactive layer (210) being arranged in said first optical cavity such that an oscillation maximum of said resonant wave (15) is present in said photoactive layer (210); and at least one optically transparent spacer layer (40) arranged in said first optical cavity between one of said mirror layers (11, 12) and said detection cell (21, 21'), A photodetector (9, 9') having The photodetector (9, 9'), characterized in that the first optoelectronic device (110, 110') has at least one external contact (60, 60'), which is in contact with an outer surface of the detection cell (21, 21'), is made of an electrically conductive material and can be electrically conductively connected to an evaluation unit for evaluating an electrical signal generated by the detection cell (21, 21') of the first optoelectronic device (110, 110').

12. 12. The photodetector (9, 9') of claim 11, characterized in that the detection cell (21, 21') arranged in the first optical cavity further comprises a first charge transport layer (211) and a second charge transport layer (212) between which the photoactive layer (210) is arranged, wherein the first charge transport layer (211), the photoactive layer (210) and the second charge transport layer (212) are arranged one on top of the other along the length of the first optical cavity.

13. A photodetector (9, 9') according to claim 11 or 12, - a first spacer layer (40) and a second spacer layer (40) are arranged in the first optical cavity as the optically transparent spacer layer (40), the first spacer layer (40) being arranged between a first one of the mirror layers (11, 12) and the detection cell (21, 21') and the second spacer layer (40) being arranged between a second one of the mirror layers (11, 12) and the detection cell (21, 21'), and the first optoelectronic device (110, 110') has as the at least one external contact (60, 60') at least two external contacts (60, 60'), whereby each one of the external contacts (60, 60') is in contact with an outer surface of the detection cell (21, 21') on a first side and with an outer surface of the detection cell (21, 21') on a second side, whereby the first side and the second side of the detection cell (21, 21') are opposite each other along the extension direction of the length of the first optical cavity, The photodetector (9, 9'),

14. In a photodetector (10) for the spectrally selective detection of electromagnetic radiation, a first optoelectronic device (111) for detecting said first wavelength of electromagnetic radiation, A first optical cavity formed by two parallel mirror layers (11, 11') spaced apart from each other, where the length (L ａ ) is designed such that, for said first wavelength, a resonant wave (15a) of order i belonging thereto is formed in said first optical cavity; and the first optoelectronic device (111), comprising at least one detection cell (21 a) arranged in the first optical cavity, each of the detection cells (21 a) including a photoactive layer (210), each of the photoactive layers (210) being arranged in the first optical cavity such that exactly one vibration maximum of the resonant wave (15 a) is present in the photoactive layer (210); and a second optoelectronic device (112) for detecting a second wavelength of said electromagnetic radiation, A second optical cavity formed by two parallel mirror layers (11', 12) spaced apart from each other, where the length of this second optical cavity (L ｂ ) is designed such that a resonant wave (15b) of order j is formed in the second optical cavity for the second wavelength; and the second optoelectronic device (112) comprising at least one detection cell (21b) arranged in the second optical cavity, each of the detection cells (21b) comprising a photoactive layer (210), each of the photoactive layers (210) being arranged in the second optical cavity such that exactly one vibration maximum of the resonant wave (15b) is present in the photoactive layer (210); A photodetector (10) comprising: the length of the second optical cavity (L ｂ ) is the length (L ａ ) and / or the order of the resonant wave (15b) belonging to the second wavelength is different from the order of the resonant wave (15a) belonging to the first wavelength, and the first optoelectronic device (111) and the second optoelectronic device (112) are arranged one on top of the other such that the extension direction of the length (L a ) of the first optical cavity and the extension direction of the length (L b ) of the second optical cavity extend along a common line, the first and second optical cavities being connected to each other by a semi-transparent mirror layer (11′) which is one of the mirror layers (11, 11′, 12) of the first optical cavity and the second optical cavity, respectively; A photodetector (10).

15. 15. The photodetector (10) according to claim 14, characterized in that the at least one detection cell (21a) arranged in the first optical cavity or the at least one detection cell (21b) arranged in the second optical cavity further comprises a first charge transport layer (211) and a second charge transport layer (212) between which the photoactive layer (210) is arranged, wherein the first charge transport layer (211), the photoactive layer (210) and the second charge transport layer (212) are arranged one on top of the other along the extension direction of the length (L a ) of the first optical cavity or along the extension direction of the length (L b ) of the second optical cavity.

16. 16. The photodetector (10) according to claim 14 or 15, characterized in that the number of detection cells (21 a) arranged in the first optical cavity and / or the number of detection cells (21 b) arranged in the second optical cavity corresponds to the order of the resonant wave (15 a) belonging to the first wavelength or the resonant wave (15 b) belonging to the second wavelength, respectively.

Images