Preparation method of infrared photosensitive element, infrared photosensitive element and infrared spectrometer

Abstract

The present disclosure relates to a method for preparing an infrared photosensitive element, an infrared photosensitive element and an infrared spectrometer, the method comprising: providing a substrate; forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers; and forming an infrared absorption layer on the side of the Bragg reflector away from the substrate and in the optical resonant cavity. In this way, the optical resonant cavity with a Bragg reflector and an infrared absorption layer are integrated by using a solution and evaporation method, which, on the one hand, simplifies the optical path structure of the spectroscopic system and reduces the occupied space; on the other hand, simplifies the production process and reduces the cost; at the same time, the Bragg reflector has a specific frequency selectivity, so that the infrared light of the band to be detected passes through the Bragg reflector and is absorbed by the infrared absorption layer. The infrared photosensitive element prepared by this method is applied to the spectrometer, so that the spectrometer has the characteristics of miniaturization, compact structure, low power consumption and portability, and can measure single-band infrared light with high accuracy and rapidity.

Description

Technical Field

[0001] The present disclosure relates to the field of optical detection technology, and in particular to a method for preparing an infrared photosensitive element, an infrared photosensitive element and an infrared spectrometer. Background Art

[0002] Spectrum analyzer, also known as spectrometer, is a scientific instrument that decomposes complex composite light into spectral lines and performs measurements and calculations. It is widely used in the fields of radiometric analysis, color measurement, chemical composition analysis, etc., and plays an important role in industries such as metallurgy, geology, hydrology, medicine, petrochemicals, environmental protection, and space exploration. In the lighting industry, spectrometers are usually used to measure the light color parameters of light sources.

[0003] A spectrometer is generally composed of a spectroscopic system, a receiving system, and a data processing system. Its working principle is to separate the complex light emitted by the light source according to different wavelengths, measure the spectral line intensity with various photoelectric detection devices, obtain the spectral power (radiation) distribution, and then calculate the color coordinates, color temperature, color rendering index, luminous flux, radiation flux and other photochromatic performance parameters. The spectroscopic system is usually made into an integral structure, called a monochromator or a polychromator. A monochromator is an optical instrument that outputs a single color spectrum line. It usually works in conjunction with a receiving system with a photomultiplier tube (PMT) detector as the core. The data processing system then calculates and processes the measurement signal, and each part is relatively independent. The polychromator is structurally closely integrated with the detector and the data processing system, and can usually directly output spectral measurement data.

[0004] Spectrometers can be classified into prism spectrometers, grating spectrometers and filter spectrometers according to the type of spectroscopic system; they can be classified into single-channel spectrometers and multi-channel spectrometers according to the number of optical paths; they can be classified into detector types, which include: PMT spectrometers and charge coupled device (CCD) spectrometers in the visible light range, and special detector types in the ultraviolet and near-infrared ranges; they can be classified into mechanical scanning spectrometers and fast scanning spectrometers according to the scanning method; they can be classified into analytical spectrometers and spectrometers for light color measurement according to the measurement object and the purpose of the measurement results. However, no matter what kind of spectrometer, it is basically composed of a spectroscopic system, a receiving system and a data processing system. Some also require a light source. Due to the complexity of multiple components and the need for optical paths and optical lengths (such as Figure 1 As shown in the figure, these spectrometers are all large in size, complex in structure, high in power consumption, and not easy to carry. Summary of the invention

[0005] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a method for preparing an infrared photosensitive element, an infrared photosensitive element and an infrared spectrometer.

[0006] The present disclosure provides a method for preparing an infrared photosensitive element, the method comprising:

[0007] providing a substrate;

[0008] An optical resonant cavity including a Bragg reflector is formed on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers;

[0009] An infrared absorption layer is formed on a side of the Bragg reflector facing away from the substrate and in the optical resonant cavity.

[0010] In some embodiments, forming the Bragg reflector on one side of the substrate comprises:

[0011] Forming N stacked composite film layers on one side of the substrate; wherein 1≤N≤4, and N is an integer;

[0012] forming an additional layer on a side of the composite film layer facing away from the substrate;

[0013] Wherein, forming each layer of the composite film comprises:

[0014] forming a first film layer;

[0015] forming a second film layer on a side of the first film layer facing away from the substrate;

[0016] The refractive index of the first film layer is greater than the refractive index of the second film layer, and the refractive index of the additional layer is greater than the refractive index of the second film layer.

[0017] In some embodiments, the thickness of the first film layer, the thickness of the second film layer, and the thickness of the additional layer satisfy:

[0018] n H t H =n L t L =n F t F =λ0 / 4;

[0019] Among them, n H represents the thickness of the first film layer, t H Represents the refractive index of the first film layer, n L represents the thickness of the second film layer, t L Represents the refractive index of the second film layer, n F represents the thickness of the additional layer, t Frepresents the refractive index of the additional layer, and λ0 represents the central wavelength of the band to be detected.

[0020] In some embodiments, the first film layer and the additional layer are formed of the same material.

[0021] In some embodiments, after forming the infrared absorption layer, the method further comprises:

[0022] A total reflection electrode layer is formed on a side of the infrared absorption layer away from the Bragg reflector; the total reflection electrode layer is used to reflect the light passing through the infrared absorption layer.

[0023] In some embodiments, after forming the Bragg reflector and before forming the infrared absorption layer, the method further comprises: forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate;

[0024] or,

[0025] After forming the infrared absorption layer and before forming the total reflection electrode layer, the method further includes: forming an optical isolation layer on a side of the infrared absorption layer facing away from the Bragg reflector.

[0026] In some embodiments, the thickness of the optical isolation layer and the infrared absorption layer satisfies:

[0027] n G t G +n A t A =m×λ0;

[0028] Among them, n G represents the thickness of the optical isolation layer, t G Represents the refractive index of the optical isolation layer, n A represents the thickness of the infrared absorption layer, t A represents the refractive index of the infrared absorption layer, and λ0 represents the central wavelength of the band to be detected.

[0029] In some embodiments, after forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate and before forming the infrared absorption layer, the method further comprises:

[0030] On the side of the optical isolation layer away from the Bragg reflector, two opposite strip electrodes are formed at two opposite edge positions of the optical isolation layer; the thickness of the strip electrodes is equal to or less than the thickness of the infrared absorption layer;

[0031] After forming the infrared absorption layer, the method further comprises:

[0032] An electrical isolation layer is formed on a side of the infrared absorption layer facing away from the optical isolation layer, and the electrical isolation layer is used to electrically isolate the strip electrodes from the total reflection electrode layer.

[0033] The present disclosure also provides an infrared photosensitive element, which is prepared by any of the above methods.

[0034] The present disclosure also provides an infrared spectrometer, which includes at least one infrared photosensitive element of any one of the above.

[0035] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0036] The disclosed embodiments provide a method for preparing an infrared photosensitive element, an infrared photosensitive element, and an infrared spectrometer, the method comprising: providing a substrate; forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers; and forming an infrared absorption layer on the side of the Bragg reflector away from the substrate and in the optical resonant cavity. In this way, the optical resonant cavity with a Bragg reflector and an infrared absorption layer are integrated by using a solution and evaporation method, the preparation process is simple, and the yield is high; at the same time, in the infrared photosensitive element prepared by this method, on the one hand, the optical path structure of the spectroscopic system is simplified, and the occupied space is reduced; on the other hand, the production process is simplified and the cost is reduced; at the same time, the Bragg reflector has a specific frequency selectivity, so that the infrared light of the band to be detected passes through the Bragg reflector and is absorbed by the infrared absorption layer. The infrared photosensitive element prepared by this method is applied to the spectrometer, so that the spectrometer has the characteristics of miniaturization, compact structure, low power consumption, and portability, and can measure single-band infrared light with high accuracy and rapidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0039] Figure 1 A schematic diagram of the working principle of a CCD polychromator in the related art;

[0040] Figure 2 A schematic diagram of a process for preparing an infrared photosensitive element provided in an embodiment of the present disclosure;

[0041] Figure 3A schematic flow chart of another method for preparing an infrared photosensitive element provided in an embodiment of the present disclosure;

[0042] Figure 4 A schematic diagram of a process for preparing another infrared photosensitive element provided in an embodiment of the present disclosure;

[0043] Figure 5 A schematic diagram of a process for preparing another infrared photosensitive element provided in an embodiment of the present disclosure;

[0044] Figure 6 A schematic diagram of a process for preparing another infrared photosensitive element provided in an embodiment of the present disclosure;

[0045] Figure 7 A schematic diagram of a process for preparing another infrared photosensitive element provided in an embodiment of the present disclosure;

[0046] Figure 8 A schematic diagram of the structure of an infrared photosensitive element provided in an embodiment of the present disclosure;

[0047] Fig. 9 A schematic diagram of the structure of another infrared photosensitive element provided in an embodiment of the present disclosure;

[0048] Fig.10 A schematic diagram of the structure of another infrared photosensitive element provided in an embodiment of the present disclosure;

[0049] Fig.11 A schematic diagram of the structure of another infrared photosensitive element provided in an embodiment of the present disclosure;

[0050] Fig.12 A schematic diagram of the working principle of an infrared photosensitive element provided in an embodiment of the present disclosure;

[0051] Fig.13 A schematic diagram of the structure of a portable quantum dot infrared spectrometer provided in an embodiment of the present disclosure;

[0052] Fig.14 A schematic diagram of the structure of a wearable device provided in an embodiment of the present disclosure;

[0053] Fig.15 A schematic diagram of the structure of another wearable device provided in an embodiment of the present disclosure.

[0054] Among them, 1. substrate; 2. optical resonant cavity; 3. infrared absorption layer; 21. Bragg reflector, 22. optical isolation layer; 23. strip electrode; 24. electrical isolation layer; 25. total reflection electrode layer; 211. first film layer; 212. second film layer; 213 additional layer; 10. infrared photosensitive element; 20. infrared spectrometer housing; 30. base; 40. optical lens; 50. external light source; 100. portable quantum dot infrared spectrometer. DETAILED DESCRIPTION

[0055] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0056] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0057] In the related technology, the spectrometer is basically composed of a spectroscopic system, a receiving system and a data processing system, such as Figure 1 The figure shows the working principle of a CCD polychromator. Figure 1 The optical fiber is used as the light source, the grating, collimator and focusing mirror constitute the spectroscopic system, the CCD detector is used as the receiving system, and the data acquisition device and the PC constitute the data processing system. The light waves emitted by the optical fiber need to be reflected multiple times by the collimator, grating and focusing mirror before they can be received by the CCD detector. The optical path is long and the structure is complex, which makes the spectrometer large in size, complex in structure, high in power consumption and not easy to carry.

[0058] In order to improve at least one of the above-mentioned defects, the present invention discloses a method for preparing an infrared photosensitive element, an infrared photosensitive element and an infrared spectrometer, the method comprising: providing a substrate; forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers; and forming an infrared absorption layer on the side of the Bragg reflector away from the substrate and in the optical resonant cavity. In this way, the optical resonant cavity with a Bragg reflector and the infrared absorption layer are integrated by using a solution and evaporation method, which simplifies the optical path structure of the spectroscopic system and reduces the occupied space on the one hand; simplifies the production process and reduces the cost on the other hand; at the same time, the Bragg reflector has a specific frequency selectivity, so that the infrared light of the band to be detected passes through the Bragg reflector and is absorbed by the infrared absorption layer. The infrared photosensitive element prepared by this method is applied to the spectrometer, so that the spectrometer has the characteristics of miniaturization, compact structure, low power consumption and portability, and can measure single-band infrared light with high accuracy and rapidity.

[0059] Combine the following Figure 2-Figure 15 , an infrared photosensitive element preparation method, an infrared photosensitive element and an infrared spectrometer provided in an embodiment of the present disclosure are exemplarily described.

[0060] In some embodiments, Figure 2 FIG. 1 is a flow chart of a method for preparing an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 2 , the method comprising:

[0061] S110 , providing a substrate.

[0062] Among them, the substrate is selected from a material with high transmittance and low absorption rate for infrared light in the range of the detection band. The specific band range can be determined according to the central wavelength of the detection band. The substrate is preferably sapphire, and other materials known to technicians in this field can also be selected, which is not limited here.

[0063] S120, forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers.

[0064] Among them, two materials with different refractive indices for infrared light in the band to be detected are alternately grown on the substrate by evaporation, molecular epitaxial growth, etc., and smooth film layers with different thicknesses are made from the two materials respectively. They are alternately stacked to jointly construct a Bragg reflector that can transmit infrared light in the band to be detected.

[0065] Both materials used to construct the Bragg reflector have the characteristics of low absorption and high transmittance for infrared light in the detection band. At the same time, the refractive index of the two materials for the infrared light in the detection band has a high difference, with an absolute difference of 1 to 1.4 or a relative difference of 1. The two materials can be selected from silicon, germanium, silicon dioxide, silicon nitride, titanium oxide, indium tin oxide and other materials. The high refractive index layer is preferably titanium pentoxide, and high refractive index silicon, CaF2, MgF2 or other high refractive index film materials can be used. The low refractive index layer is preferably silicon dioxide, ZnSe or other low refractive index film materials.

[0066] The material requirements for the optical resonant cavity are similar to those for the Bragg reflector, requiring high transmittance and low absorption of infrared light in the detection band, and a certain refractive index for infrared light.

[0067] In other embodiments, the two materials for constructing the Bragg reflector may also be other materials known to those skilled in the art, which are not limited here.

[0068] S130, forming an infrared absorption layer on a side of the Bragg reflector facing away from the substrate and in the optical resonant cavity.

[0069] The infrared absorption layer is formed on the side of the Bragg reflector away from the substrate by mask spraying, drop coating or spin coating. The infrared absorption layer is an infrared quantum dot layer, which is set according to the corresponding band range of the infrared light transmitted by the Bragg reflector; the quantum dot material can be selected from perovskite, ZnSe, ZnS, HgTe, PbS, ZnSe / ZnS, ZnSe / ZnO, CdSe, CdTe, CdSe / CdS, InP / ZnS, InP / ZnSe / ZnS, InP / InAs, PbS, PbSe, PbTe, CuInS2, CuInSe2, etc.; the thickness of the infrared absorption layer is 100-1000nm.

[0070] The all-liquid phase method for synthesizing infrared quantum dots has a high success rate, high output, and low cost compared to other synthesis methods of infrared narrow-band semiconductor materials. It can be used to solve the problem of difficulty in producing infrared materials.

[0071] The method for preparing the infrared photosensitive element provided in the embodiment of the present disclosure includes providing a substrate; forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers; and forming an infrared absorption layer on the side of the Bragg reflector away from the substrate and in the optical resonant cavity. In this way, the optical resonant cavity with a Bragg reflector and the infrared absorption layer are integrated by using a solution and evaporation method, which simplifies the optical path structure of the spectroscopic system and reduces the occupied space on the one hand; simplifies the production process and reduces the cost on the other hand; at the same time, the Bragg reflector has a specific frequency selectivity, so that the infrared light of the band to be detected passes through the Bragg reflector and is absorbed by the infrared absorption layer. The infrared photosensitive element prepared by this method is applied to a spectrometer, so that the spectrometer has the characteristics of miniaturization, compact structure, low power consumption, and portability, and can measure single-band infrared light with high accuracy and rapidity.

[0072] In some embodiments, Figure 3 FIG. 1 is a flow chart of another method for preparing an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 2 Based on Figure 3 In S120, a Bragg reflector is formed on one side of the substrate, which may specifically include:

[0073] S121. Forming N stacked composite film layers on one side of the substrate; wherein 1≤N≤4, and N is an integer.

[0074] The formation of each composite film layer includes: forming a first film layer; forming a second film layer on the side of the first film layer away from the substrate; the number of layers is 1 to 4, which can be adjusted according to the center frequency of the waveband to be detected.

[0075] The refractive index of the first film layer is greater than that of the second film layer, and the absolute difference between the two refractive indices is 1 to 1.4 or the relative difference is 1 times; the first film layer is preferably titanium pentoxide, and can be made of high refractive index silicon, CaF2, MgF2 and other materials. The second film layer is preferably silicon dioxide or ZnSe.

[0076] S122, forming an additional layer on the side of the composite film layer facing away from the substrate.

[0077] The refractive index of the additional layer is greater than that of the second film layer; the material of the additional layer may be the same as or different from that of the first film layer, which is not limited here.

[0078] In the method for preparing the infrared photosensitive element provided by the embodiment of the present disclosure, the film layer structure of the Bragg reflector is formed by alternating the first film layer with a high refractive index and the second film layer with a low refractive index, and an additional layer with a high refractive index is formed on the last second film layer with a low refractive index. In this way, the formed Bragg reflector structure is formed by alternating periodic film layers with high refractive index and low refractive index, and each film layer boundary will cause partial reflection of the light wave. The infrared light in the band to be detected is reflected multiple times in the Bragg reflector structure, so that more infrared light in the band to be detected passes through the Bragg reflector, and then more infrared light in the band to be detected is absorbed by the infrared absorption layer.

[0079] In some embodiments, the thickness of the first film layer, the thickness of the second film layer, and the thickness of the additional layer satisfy: n H t H =n L t L =n F t F =λ0 / 4; where n H represents the thickness of the first film layer, t H Represents the refractive index of the first film layer, n L represents the thickness of the second film layer, t L Represents the refractive index of the second film layer, n F represents the thickness of the additional layer, t F represents the refractive index of the additional layer, and λ0 represents the central wavelength of the band to be detected.

[0080] In this way, the thickness of the first film layer, the thickness of the second film layer and the thickness of the additional layer of the Bragg reflector satisfy n H t H =n L t L =n F t F =λ0 / 4, the optical path difference of the reflected light at the interface of adjacent film layers is half a wavelength, and the sign of the reflection coefficient at the interface will also change. Therefore, all the reflected light at the interface undergoes destructive interference, resulting in strong reflected light.

[0081] In some embodiments, the first film layer and the additional layers are formed from the same material.

[0082] The additional layer and the first film layer are made of the same material and both have a high refractive index. The structure of the Bragg reflector formed in this way changes regularly, and the film layers with high refractive index and low refractive index are arranged alternately and periodically.

[0083] In some embodiments, Figure 4 FIG. 1 is a flow chart of another method for preparing an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 2 Based on Figure 4 After forming the infrared absorption layer in S130, the method may further include:

[0084] S140, forming a total reflection electrode layer on a side of the infrared absorption layer away from the Bragg reflector; the total reflection electrode layer is used to reflect light passing through the infrared absorption layer.

[0085] The full-emission electrode layer has a high reflectivity to infrared light; the full-emission electrode layer can be a metal layer, preferably gold, with a film thickness of 100-1000nm.

[0086] In this way, the fully emitting electrode layer reflects the infrared light that has passed through the infrared absorption layer but has not been absorbed back to the infrared absorption layer, and the infrared light in two opposite directions in the infrared absorption layer undergoes constructive interference, thereby enhancing the intensity of the infrared light and further enhancing the infrared absorption layer's absorption rate of the infrared light.

[0087] In some embodiments, after forming the Bragg reflector and before forming the infrared absorption layer, the method may further include forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate.

[0088] For example, Figure 5 FIG. 1 is a flow chart of another method for preparing an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 5 , the method may include:

[0089] S210 , providing a substrate.

[0090] S220, forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers.

[0091] S230, forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate.

[0092] Among them, the function of the optical isolation layer is to adjust the optical path of infrared light between the Bragg reflector-optical isolation layer-infrared absorption layer-total reflection electrode layer, so that the infrared light can oscillate and interfere and enhance here, thereby increasing the absorption rate of the infrared absorption layer; the thickness of the optical isolation layer is determined by the central wavelength of the band to be detected and the thickness of the infrared absorption layer.

[0093] The optical isolation layer is made of a material with a low refractive index and extremely low or no absorption of infrared light, preferably silicon dioxide; and is produced by mask evaporation, molecular epitaxial growth, and the like.

[0094] S240, forming an infrared absorption layer on a side of the optical isolation layer facing away from the substrate and in the optical resonant cavity.

[0095] S250, forming a total reflection electrode layer on a side of the infrared absorption layer facing away from the Bragg reflector.

[0096] At this point, the infrared photosensitive element is formed.

[0097] In some embodiments, after forming the infrared absorption layer and before forming the total reflection electrode layer, the method may further include: forming an optical isolation layer on a side of the infrared absorption layer facing away from the Bragg reflector.

[0098] For example, Figure 6 FIG. 1 is a flow chart of another method for preparing an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 6 , the method may include:

[0099] S310 , providing a substrate.

[0100] S320, forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers.

[0101] S330, forming an infrared absorption layer on a side of the Bragg reflector facing away from the substrate and in the optical resonant cavity.

[0102] S340, forming an optical isolation layer on a side of the infrared absorption layer facing away from the Bragg reflector.

[0103] Among them, the function of the optical isolation layer is to adjust the optical path of infrared light between the Bragg reflector-infrared absorption layer-optical isolation layer-total reflection electrode layer, so that it can oscillate and interfere and enhance here, thereby increasing the absorption rate of the infrared absorption layer; its thickness is determined by the central wavelength of the band to be detected and the thickness of the infrared absorption layer.

[0104] The optical isolation layer is made of a material with a low refractive index and extremely low or no absorption of infrared light, preferably silicon dioxide; and is produced by mask evaporation, molecular epitaxial growth, and the like.

[0105] S350, forming a total reflection electrode layer on a side of the optical isolation layer away from the Bragg reflector.

[0106] At this point, the infrared photosensitive element is formed.

[0107] In some embodiments, the thickness of the optical isolation layer and the infrared absorption layer satisfies:

[0108] n G t G +n A t A =m×λ0.

[0109] Among them, n G represents the thickness of the optical isolation layer, t G Represents the refractive index of the optical isolation layer, n A represents the thickness of the infrared absorption layer, t A represents the refractive index of the infrared absorption layer, and λ0 represents the central wavelength of the band to be detected.

[0110] Wherein, m is a positive integer, indicating that the sum of the optical paths of the infrared light in the optical isolation layer and the infrared absorption layer is an integer multiple of the central wavelength of the band to be detected.

[0111] In some embodiments, after forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate and before forming the infrared absorption layer, the method may further include: forming two opposite strip electrodes at two opposite edge positions of the optical isolation layer on the side of the optical isolation layer facing away from the Bragg reflector; the thickness of the strip electrodes is equal to or less than the thickness of the infrared absorption layer; and further, after forming the infrared absorption layer, the method may further include: forming an electrical isolation layer on a side of the infrared absorption layer facing away from the optical isolation layer, the electrical isolation layer being used to electrically isolate the strip electrodes from the total reflection electrode layer.

[0112] For example, Figure 7 FIG. 1 is a flow chart of another method for preparing an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 7 , the method may include:

[0113] S410 , providing a substrate.

[0114] S420, forming an optical resonant cavity including a Bragg reflector on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers.

[0115] S430, forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate.

[0116] S440, forming two opposite strip electrodes at two opposite edge positions of the optical isolation layer on a side of the optical isolation layer away from the Bragg reflector; the thickness of the strip electrodes is equal to or less than the thickness of the infrared absorption layer.

[0117] Exemplarily, the strip electrodes may be made of a metal material with high conductivity and strong stability, such as aluminum, silver, gold, copper, etc., preferably silver.

[0118] Exemplarily, the strip electrodes can be manufactured by mask evaporation, magnetron sputtering, etc., with a thickness of 100 nm to 1000 nm.

[0119] S450, forming an infrared absorption layer on a side of the optical isolation layer away from the Bragg reflector and in the optical resonant cavity.

[0120] S460, forming an electrical isolation layer on a side of the infrared absorption layer away from the optical isolation layer.

[0121] The electrical isolation layer is used to achieve electrical isolation between the total reflection electrode layer and the strip electrodes to prevent short circuit between the two.

[0122] Exemplarily, the electrical isolation layer can be made by spin coating or molecular epitaxial growth method; epoxy resin (PMMA) is preferred, and the film thickness is as thin as possible to completely electrically isolate the strip electrodes from the total reflection electrode layer.

[0123] At the same time, the electrical isolation layer has very low or no absorption of infrared light.

[0124] S470, forming a total reflection electrode layer on a side of the electrical isolation layer facing away from the Bragg reflector.

[0125] At this point, the optical photosensitive element is formed.

[0126] On the basis of the above-mentioned embodiments, the embodiments of the present disclosure further provide an infrared photosensitive element, which can be prepared by any of the preparation methods provided in the above-mentioned embodiments and has corresponding beneficial effects. The similarities can be understood by referring to the above and will not be repeated here.

[0127] Combine the following Figure 8-Figure 12 , an infrared photosensitive element provided in an embodiment of the present disclosure is exemplarily described.

[0128] For example, Figure 8 FIG. 1 is a schematic diagram of the structure of an infrared photosensitive element provided by an embodiment of the present disclosure. Figure 8 The infrared photosensitive element includes a substrate 1, an optical resonant cavity 2 and an infrared absorption layer 3; the optical resonant cavity 2 is arranged on one side of the substrate 1, and the optical resonant cavity 2 includes a Bragg reflector 21 composed of stacked film layers; the infrared absorption layer 3 is arranged in the optical resonant cavity 2.

[0129] For example, Fig. 9 or Fig.10FIG. 1 is a schematic diagram of the structure of another infrared photosensitive element provided by an embodiment of the present disclosure. Fig. 9 or Fig.10 In the infrared photosensitive element, the film layers are, from bottom to top, a substrate 1, a Bragg reflector 21, an optical isolation layer 22, a strip electrode 23, an infrared absorption layer 3, an electrical isolation layer 24, and a total reflection electrode layer 25. The optical isolation layer 22 is arranged between the Bragg reflector 21 and the infrared absorption layer 3; wherein the Bragg reflector 21 is composed of three composite film layers and one additional layer 213, each composite film layer is composed of a first film layer 211 and a second film layer 212, and the first film layer 211 is located on the side of the second film layer 212 facing the substrate 1; two strip electrodes 23 are arranged at two opposite edge positions of the infrared absorption layer, and are in electrical contact with the infrared absorption layer 3.

[0130] For example, Fig.11 FIG. 1 is a schematic diagram of the structure of another infrared photosensitive element provided by an embodiment of the present disclosure. Fig.11 From bottom to top, there are substrate 1, Bragg reflector 21, strip electrode 23, infrared absorption layer 3, optical isolation layer 22, and total reflection electrode layer 25. The infrared absorption layer 3 is arranged between the optical isolation layer 22 and the Bragg reflector 21. Among them, the Bragg reflector 21 is composed of 3 composite film layers and 1 additional layer 213. Each composite film layer is composed of a first film layer 211 and a second film layer 212. The first film layer 211 is located on the side of the second film layer 212 facing the substrate 1. Two strip electrodes 23 are arranged at the opposite edge positions of the infrared absorption layer and are in electrical contact with the infrared absorption layer 3.

[0131] It is understandable that Figure 9-11 The Bragg reflector 21 is shown as including three composite film layers, but does not limit the infrared photosensitive element provided by the embodiment of the present disclosure. In other embodiments, the Bragg reflector 21 may also include 1, 2, 4 or more composite film layers, which is not limited here.

[0132] For example, Fig.12 FIG. 1 is a schematic diagram showing the working principle of an infrared photosensitive element provided by an embodiment of the present disclosure. Fig.12, an external light source provides illumination and projects infrared light to the detection object. The infrared light reflected by the detection object passes through the substrate and then passes through the Bragg reflector in the optical resonant cavity. The infrared light of a specific center frequency passes through the Bragg reflector and constructively interferes at the back, thereby enhancing the intensity of its center frequency wavelength, thereby narrowing the spectrum of the incident infrared light; the infrared light with a narrowed spectrum width passes through the optical isolation layer and is partially absorbed by the infrared absorption layer, and the rest is reflected on the total reflection electrode layer and returns to the infrared absorption layer area, where the infrared lights in two opposite directions in the infrared absorption layer constructively interfere, thereby enhancing the intensity of the infrared light, further narrowing the spectrum width, and thereby enhancing the absorptivity of the infrared absorption layer.

[0133] In some embodiments, Fig.13 FIG. 1 is a schematic diagram of the structure of an infrared spectrometer provided by an embodiment of the present disclosure. Fig.13 , the infrared spectrometer includes at least one of the above-mentioned infrared photosensitive elements.

[0134] For example, Fig.13 As shown, four infrared photosensitive elements 10 of different wavebands are spliced ​​and combined, and the infrared photosensitive element 10, the base 30, and the optical lens 40 are installed in the infrared spectrometer housing 20 in sequence; in this way, the infrared spectrometer can detect four different infrared bands at the same time.

[0135] It is understandable that Fig.13 The splicing and combination of four infrared photosensitive elements is only exemplified, but does not constitute a limitation on the infrared spectrometer provided by the embodiment of the present disclosure. In other embodiments, the number of splicing and combination of infrared photosensitive elements can be set according to the requirements of the multi-band infrared spectrometer and is not limited here.

[0136] For example, Fig.14 or Fig.15 As shown, the portable quantum dot infrared spectrometer 100 is embedded on the edge of a watch dial (i.e., a structural form of a wearable device), and an external light source 50 is arranged on the dial to provide lighting for the portable quantum dot infrared spectrometer 100.

[0137] It should be noted that the portable quantum dot infrared spectrometer can also be applied to other wearable devices known to technicians in this field, such as smart bracelets, glasses, headwear, jewelry, and clothing, or applied to other terminal devices with detection functions, which are not limited here.

[0138] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0139] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an infrared photosensitive element, characterized in that: include: providing a substrate; An optical resonant cavity including a Bragg reflector is formed on one side of the substrate; wherein the Bragg reflector is formed by stacking film layers; forming an infrared absorption layer on a side of the Bragg reflector facing away from the substrate and in the optical resonant cavity; After forming the infrared absorption layer, the method further comprises: A total reflection electrode layer is formed on a side of the infrared absorption layer away from the Bragg reflector; the total reflection electrode layer is used to reflect light passing through the infrared absorption layer; After forming the Bragg reflector and before forming the infrared absorption layer, the method further includes: forming an optical isolation layer on the side of the Bragg reflector away from the substrate, or, after forming the infrared absorption layer and before forming the total reflection electrode layer, the method further includes: forming an optical isolation layer on the side of the infrared absorption layer away from the Bragg reflector; the thicknesses of the optical isolation layer and the infrared absorption layer satisfy: nG tG+nA tA=m×λ0; wherein nG represents the thickness of the optical isolation layer, tG represents the refractive index of the optical isolation layer, nA represents the thickness of the infrared absorption layer, tA represents the refractive index of the infrared absorption layer, and λ0 represents the center wavelength of the band to be detected; wherein m is a positive integer, indicating that the sum of the optical paths of the infrared light in the optical isolation layer and the infrared absorption layer is an integer multiple of the center wavelength of the band to be detected.

2. The method according to claim 1, characterized in that Forming the Bragg reflector on one side of the substrate comprises: Forming N stacked composite film layers on one side of the substrate; wherein 1≤N≤4, and N is an integer; forming an additional layer on a side of the composite film layer facing away from the substrate; Wherein, forming each layer of the composite film comprises: forming a first film layer; forming a second film layer on a side of the first film layer facing away from the substrate; The refractive index of the first film layer is greater than the refractive index of the second film layer, and the refractive index of the additional layer is greater than the refractive index of the second film layer.

3. The method according to claim 2, characterized in that The thickness of the first film layer, the thickness of the second film layer and the thickness of the additional layer satisfy: n H t H =n L t L =n F t F =λ0 / 4; Among them, n H represents the thickness of the first film layer, t H Represents the refractive index of the first film layer, n L represents the thickness of the second film layer, t L Represents the refractive index of the second film layer, n F represents the thickness of the additional layer, t F represents the refractive index of the additional layer, and λ0 represents the central wavelength of the band to be detected.

4. The method according to claim 2, characterized in that: The first film layer and the additional layer are formed of the same material.

5. The method according to claim 1, characterized in that After forming an optical isolation layer on a side of the Bragg reflector facing away from the substrate and before forming the infrared absorption layer, the method further comprises: On the side of the optical isolation layer away from the Bragg reflector, two opposite strip electrodes are formed at two opposite edge positions of the optical isolation layer; the thickness of the strip electrodes is equal to or less than the thickness of the infrared absorption layer; After forming the infrared absorption layer, the method further comprises: An electrical isolation layer is formed on a side of the infrared absorption layer facing away from the optical isolation layer, and the electrical isolation layer is used to electrically isolate the strip electrodes from the total reflection electrode layer.

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