Infrared narrow-band optoelectronic device and method for manufacturing same

Abstract

The application discloses an infrared narrow-band photoelectric device and a preparation method thereof, and comprises the following steps: after an electron transport layer is prepared on FTO glass, an active absorption layer is prepared on the electron transport layer, the active absorption layer is treated by cadmium chloride to passivate defects, a cuprous thiocyanate layer or a nickel oxide layer is prepared on the active absorption layer as a hole transport layer, when the hole transport layer is the nickel oxide layer, a cuprous thiocyanate layer is prepared on the hole transport layer, copper is diffused to the FTO glass interface by annealing the cuprous thiocyanate layer at 250±5 DEG C for 10-30 min, and a transparent electrode is prepared on the surface of the cuprous thiocyanate layer. After the cuprous thiocyanate layer is prepared, high-temperature annealing treatment is carried out, copper is fully diffused and doped into the active absorption layer, the P-type doping concentration is improved, an extremely narrow built-in electric field is obtained, the carrier collection is narrowed, and the infrared narrow-band photoelectric device has the advantages of high stability, long service life, fast response speed, high responsivity, strong waveband selectivity, wide and adjustable response waveband, narrow half-height width and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric devices, in particular to an infrared narrow-band photoelectric device and a preparation method thereof. BACKGROUND

[0002] The existing infrared narrow-band photoelectric device mainly realizes the narrow-band detection effect by integrating a band-pass filter with a common wide-band photoelectric device, but the introduction of the filter will cause additional optical loss, reduce the quantum efficiency, and the spectral tuning needs to be adjusted by a mechanical filter, which is difficult to realize dynamic adjustment.

[0003] Although the use of carrier collection narrowing mechanism to realize single infrared band selective detection can avoid the use of filters, the implementation of collection narrowing is highly dependent on a relatively thick active layer film (> 10 μm), which reduces the response speed (> 1 ms) and spectral selectivity (full width at half maximum FWHM > 50 nm), thereby limiting the detection accuracy and making it difficult to meet the high-precision detection requirements.

[0004] Therefore, it is of great significance to develop a narrow-band photoelectric device without filters to achieve excellent carrier collection narrowing effect, while obtaining good response speed and response band selectivity. SUMMARY

[0005] The present application aims at the deficiencies in the prior art, and provides an infrared narrow-band photoelectric device and a preparation method thereof, which uses a relatively thin absorption layer (1-6 μm) to realize carrier collection narrowing effect by regulating the width of the space charge region, while obtaining excellent light response (EQE > 30%) and detection band selectivity (full width at half maximum ~ 20 nm), and the response time is as low as about 300 ns. In addition, the band gap of the active absorption layer can be regulated to realize wide-range adjustment of the response band between 560 nm and 850 nm.

[0006] To solve the above technical problems, the first aspect of the present application provides a preparation method of an infrared narrow-band photoelectric device, comprising the following steps:

[0007] S1, after preparing an electron transport layer on an FTO glass, an active absorption layer is prepared on the electron transport layer;

[0008] The material of the active absorption layer is Cd 1-x Zn x Te or CdSe y Te 1-y , 0≤x≤1, 0≤y≤1;

[0009] S2, after the active absorption layer is treated with cadmium chloride to passivate defects, a cuprous thiocyanate layer or a nickel oxide layer is prepared on the active absorption layer as a hole transport layer.

[0010] wherein, when the hole transport layer is a nickel oxide layer, a cuprous thiocyanate layer is prepared on the hole transport layer;

[0011] S3, annealing at 250±5 DEG C for 10-30 min to diffuse copper to the FTO glass interface;

[0012] S4, preparing a transparent electrode on the surface of the cuprous thiocyanate layer.

[0013] The present application carries out high-temperature annealing treatment after preparing the cuprous thiocyanate layer, so that the copper is fully diffused to the FTO glass surface, the P-type doping concentration of the active absorption layer is improved, and an extremely narrow built-in electric field (<400 nm) is caused. At this time, the ultraviolet and visible light are absorbed by the neutral region and are difficult to penetrate to the space charge region, so as to be difficult to be collected by the external circuit; and the near-infrared spectrum has a deep penetration depth and can reach the built-in electric field region, so that the photo-generated electron / hole pairs can be efficiently separated and transported under the action of the built-in electric field, thereby realizing the response of the device to the narrow spectrum.

[0014] The active absorption layer of the present application adopts Cd 1-x Zn x Te or CdSe y Te 1-y , the values of x and y are adjusted to control the band gap of the active light absorption layer, and the purpose of wide adjustable response wavelength between 560-850 nm is achieved; in summary, the narrow-band photoelectric device of the present application can realize selective absorption and selective response of different wavebands.

[0015] Further, the thickness of the electron transport layer is 30-60 nm, the thickness of the active absorption layer is 1-6 microns, and the thickness of the hole transport layer is 30-60 nm.

[0016] Further, in S2, the cadmium chloride treatment is specifically: after coating the cadmium chloride solution on the active absorption layer, heat treatment is carried out at 390-420 DEG C and 600-700 torr for 20-60 min. Through the calcium chloride treatment, the defects are passivated, the grain growth is promoted, and the subsequent copper diffusion doping is facilitated.

[0017] Further, in S1, the material of the electron transport layer is cadmium sulfide, tin oxide or zinc magnesium oxide, and the electron transport layer is prepared by a radio frequency magnetron sputtering method, a chemical water bath deposition method or a spin coating method.

[0018] Further, in S1, the active absorption layer is prepared by a near-space sublimation method, a magnetron sputtering method, a thermal evaporation method or a chemical vapor deposition method.

[0019] Further, in S2, the cuprous thiocyanate layer and the nickel oxide layer are prepared by a magnetron sputtering method or a spin coating method.

[0020] Further, in S4, the transparent electrode material is ITO, which is prepared by a magnetron sputtering method.

[0021] The second aspect of the present application provides the infrared narrow-band optoelectronic device prepared by the preparation method of the first aspect.

[0022] Further, the infrared narrow-band optoelectronic device has a spectral half-width of 20±10 nm and a light response EQE>30%.

[0023] Further, the infrared narrow-band optoelectronic device can realize wide-range adjustment of the response waveband between 560 nm and 850 nm by adjusting the band gap of the active absorption layer.

[0024] Advantages of the present application:

[0025] The present application performs high-temperature annealing treatment after preparing the cuprous thiocyanate layer, so that copper is fully diffused and doped into the active absorption layer, the P-type doping concentration of the active absorption layer is improved, an extremely narrow built-in electric field is obtained, the carrier collection is narrowed, and the infrared narrow-band optoelectronic device has the advantages of high stability, long service life, fast response speed, high responsivity, strong waveband selectivity, wide-range adjustable response waveband, narrow half-width, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below are only embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0027] Figure 1 is a structural schematic diagram of the infrared narrow-band optoelectronic device of the present application;

[0028] Figure 2 is a spectral response schematic diagram of the copper fully diffused in the narrow-band optoelectronic device;

[0029] Figure 3 is a spectral response schematic diagram of the copper not fully diffused in the narrow-band optoelectronic device;

[0030] Figure 4 is a copper concentration change curve of the infrared narrow-band optoelectronic device of Example 1 perpendicular to the plane direction;

[0031] Figure 5 is the EDS test result of the active absorption layer of Example 2;

[0032] Figure 6 is the XRD test result of the active absorption layer of Example 3;

[0033] Figure 7is a spectral response graph of the infrared narrow-band optoelectronic device obtained in Example 1 and Comparative Examples 1-2;

[0034] Figure 8 is a spectral response graph of the narrow-band optoelectronic device of Example 1, Example 2 and Example 3. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described clearly and completely below in conjunction with specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] The present embodiment provides a preparation method of an infrared narrow-band optoelectronic device, comprising the following steps:

[0037] S1, after preparing an electron transport layer on FTO glass, the thickness of the electron transport layer is 30-60 nm, an active absorption layer is prepared on the electron transport layer, and the thickness of the active absorption layer is 1-6 μm;

[0038] The material of the active absorption layer is Cd 1-x Zn x Te or CdSe y Te 1-y , 0≤x≤1, 0≤y≤1;

[0039] S2, after passivating defects by cadmium chloride treatment on the active absorption layer, a cuprous thiocyanate layer or a nickel oxide layer is prepared on the active absorption layer as a hole transport layer, and the thickness of the hole transport layer is 30-60 nm;

[0040] When the hole transport layer is a nickel oxide layer, a cuprous thiocyanate layer is prepared on the hole transport layer.

[0041] S3, annealing at 250±5℃ for 10-30 min to diffuse copper to the interface of FTO glass;

[0042] S4, preparing a transparent electrode on the surface of the cuprous thiocyanate layer to obtain a narrow-band optoelectronic device, as shown in Figure 1 .

[0043] Reference Figure 2For example, taking CdTe active absorption layer, CdS electron transport layer and CuSCN hole transport layer as an example, after the preparation of the cuprous thiocyanate layer, high-temperature annealing treatment is performed, so that the copper is fully diffused to the surface of the FTO glass, the P-type doping concentration of the active absorption layer is improved, and an extremely narrow built-in electric field (<400 nm) is caused. At this time, the ultraviolet and visible light are absorbed by the neutral region and are difficult to penetrate to the space charge region, so as to be difficult to be collected by the external circuit. The near-infrared spectrum has a relatively deep penetration depth and can reach the built-in electric field region. Under the action of the built-in electric field, the photo-generated electron / hole pairs can be efficiently separated and transported, so that the device can respond to narrow spectrum. When the copper diffusion treatment is not performed or the diffusion is insufficient, the doping level is low, the built-in electric field is wide, and the neutral region is narrow. The light with low penetration depth can penetrate through the neutral region to reach the space charge region. The generated carriers can be collected under the action of the built-in electric field in the space charge region, so as to form a broadband response, as shown in FIG. 1. Figure 3 The active absorption layer is CdTe or CdSe 1-x Zn x Te or CdSe y Te 1-y The values of x and y are adjusted to control the band gap of the active light absorption layer, so as to realize the purpose of adjusting the response waveband in a wide range of 560-850 nm. In summary, the narrow-band photoelectric device can realize selective absorption and selective response of different wavebands.

[0044] As a preferred embodiment, in S2, the cadmium chloride treatment specifically includes: after the active absorption layer is coated with a cadmium chloride solution, heat treatment is performed at 390-420°C and 600-700 torr for 20-60 min. Through the calcium chloride treatment, defects are passivated, and grain growth is promoted, so as to facilitate subsequent copper diffusion doping.

[0045] As a preferred embodiment, the material of the electron transport layer is cadmium sulfide, tin oxide or zinc magnesium oxide, and the electron transport layer is prepared by a radio frequency magnetron sputtering method, a chemical water bath deposition method or a spin coating method. The active absorption layer is prepared by a near-space sublimation method, a magnetron sputtering method, a thermal evaporation method or a chemical vapor deposition method. The cuprous thiocyanate layer and the nickel oxide layer are prepared by a magnetron sputtering method or a spin coating method. The material of the transparent electrode is ITO, which is prepared by a magnetron sputtering method.

[0046] Another embodiment provides an infrared narrow-band photoelectric device prepared by the preparation method described in the above embodiment. The spectral half-width of the infrared narrow-band photoelectric device is 20±10 nm, and the light response EQE is greater than 30%. The response waveband of the infrared narrow-band photoelectric device can be adjusted in a wide range of 560-850 nm by adjusting the band gap of the active absorption layer.

[0047] Embodiment 1

[0048] The embodiment relates to a preparation method of an infrared narrow-band photoelectric device, and comprises the following steps:

[0049] (1) ultrasonic cleaning of FTO glass using deionized water mixed with Micro-90 cleaning agent.

[0050] (2) preparation of an electron transport layer by a magnetron sputtering method: the FTO glass is placed in a magnetron sputtering chamber for sputtering film deposition, the air pressure is stabilized to 1-10 Pa, the power is 50 W, the substrate is rotated (25 r / min), and a 40 nm-thick cadmium sulfide (CdS) film is deposited by sputtering film deposition.

[0051] (3) preparation of an active absorption layer by a close space sublimation method: cadmium telluride (CdTe) powder is poured into a graphite groove, a silicon nitride-coated graphite sheet is placed above the groove, and the graphite sheet is pressed by a graphite block, a cadmium telluride source is prepared by close space sublimation, wherein the upper temperature zone is set to 550 DEG C, the lower temperature zone is set to 700 DEG C, the air pressure is set to 5 torr, and the time is 40 min. The prepared cadmium telluride source is placed in the graphite groove, the FTO glass coated with the cadmium sulfide in step (2) is covered above the groove and compacted by the graphite block, and a cadmium telluride active absorption layer with a thickness of about 3 microns is prepared by close space sublimation, wherein the upper temperature zone is set to 550 DEG C, the lower temperature zone is set to 700 DEG C, and the air pressure is set to 15 torr.

[0052] (4) cadmium chloride treatment of the cadmium telluride: cadmium chloride methanol solution is coated on the surface of the cadmium telluride, and is baked on an 80 DEG C hot table, then the sample is inverted on the graphite groove for heat treatment, wherein the temperature is set to 400 DEG C, the air pressure is 650 torr, and the time is 20 min.

[0053] (5) spin coating of cuprous thiocyanate: the residual cadmium chloride on the surface of the cadmium telluride film treated by the cadmium chloride is washed away, then 3 mg / ml of cuprous thiocyanate aqueous ammonia solution is spin coated on the surface and is spun dry, finally, the product is annealed on a hot table at 250 DEG C for 20 min, so that copper is diffused to the front interface.

[0054] (6) magnetron sputtering of a transparent electrode: the annealed product is placed in a magnetron sputtering chamber for sputtering film deposition, the air pressure is stabilized to 0.3-1 Pa, the power is 70 W, the substrate is rotated (25 r / min), and an ITO transparent electrode is deposited by sputtering film deposition.

[0055] The copper concentration change of the infrared narrow-band photoelectric device obtained in the embodiment in the vertical direction of the plane is shown in FIG. 1. Figure 4 As shown in FIG. 1, through the annealing treatment in step (5), copper is fully diffused in the photoelectric device and is enriched on the FTO glass side.

[0056] Example 2

[0057] The embodiment is different from embodiment 1 in that the electron transport layer is replaced by tin oxide prepared by a chemical water bath deposition method, and the active absorption layer is replaced by CdSe prepared by a thermal evaporation method 0.23 Te 0.77 , other steps and parameters remain unchanged, specifically:

[0058] (1) The FTO glass is cleaned by ultrasonic cleaning with deionized water mixed with Micro-90 cleaning agent.

[0059] (2) The electron transport layer is prepared by a chemical water bath deposition method: a 0.1M tin tetrachloride deionized water solution is used, and 0.2M hydrogen peroxide solution is added to promote oxidation. The glass is vertically placed in the solution (the liquid level is 1-2 cm higher than the substrate), and a 40 nm thick tin oxide is deposited under the conditions of a temperature of 80°C and a magnetic stirring speed of 150 rpm;

[0060] (3) The active absorption layer is prepared by a thermal evaporation method: the sample is fixed in an evaporation chamber for thermal evaporation, and a CdSe layer with a thickness of about 3μm is prepared by a cadmium telluride and cadmium selenide evaporation source at a temperature of 250°C 0.23 Te 0.77 The EDS detection result of the active absorption layer is shown in Figure 5 .

[0061] (4) The CdSe 0.23 Te 0.77 is treated with cadmium chloride: cadmium chloride methanol solution is coated on the surface of the CdSe 0.23 Te 0.77 , and is baked on a hot stage at 80°C, and then the sample is inverted on a graphite groove for heat treatment, wherein the temperature is set at 400°C, the gas pressure is 650torr, and the time is 20 min.

[0062] (5) Cuprous thiocyanate is prepared by spin coating: the remaining cadmium chloride on the surface of the cadmium telluride film treated with cadmium chloride is washed away, then 3mg / ml cuprous thiocyanate aqueous ammonia solution is spin-coated on the surface and dried, and finally the hot stage is used for annealing at 250°C for 20 min to diffuse copper to the front interface.

[0063] (6) Transparent electrode by magnetron sputtering: the product after annealing is placed in a magnetron sputtering chamber for sputtering and film deposition, the gas pressure is stabilized to 0.3-1 Pa, the power is 70 W, the substrate is rotated (25 r / min), and the ITO transparent electrode is sputtered and deposited.

[0064] Embodiment 3

[0065] The embodiment is different from embodiment 1 in that the electron transport layer is zinc magnesium oxide, and the active absorption layer is Cd 1-x Zn xTe, the space transmission layer is nickel oxide, and cuprous thiocyanate is spin-coated on the surface of the nickel oxide, specifically:

[0066] (1) The FTO glass is cleaned by ultrasonic cleaning with deionized water mixed with Micro-90 cleaning agent.

[0067] (2) Electron transport layer prepared by magnetron sputtering method: The FTO glass is placed in the magnetron sputtering chamber for sputtering film deposition, the gas pressure is stabilized to 1-10 Pa, the power is 50 W, the substrate is rotated (25 r / min), and 40 nm thick zinc magnesium oxide is deposited by sputtering film deposition.

[0068] (3) Preparation of active absorption layer by near-space sublimation method: the prepared Cd 1-x Zn x Te source is placed in a graphite groove, the FTO glass coated with zinc magnesium oxide in step (2) is placed above the groove and compacted with a graphite block, and a Cd 1-x Zn x Te active absorption layer with a thickness of about 3 μm is prepared by near-space sublimation, wherein the upper temperature zone is set to 500℃, the lower temperature zone is set to 650℃, and the gas pressure is set to 15 torr; wherein x is 0, 0.05, 0.1, 0.2, 0.3, 0.4, 1, and part of the Cd 1-x Zn x Te XRD detection results are shown in Figure 6 It can be seen that the band gap can be adjusted by adjusting the material of the active absorption layer.

[0069] (4) CdCl2 treatment of Cd 1-x Zn x Te: CdCl2 methanol solution is coated on the surface of Cd 1-x Zn x Te, and baked on an 80℃ hot stage, then the sample is inverted on a graphite groove for heat treatment, wherein the temperature is set to 400℃, the gas pressure is 650 torr, and the time is 20 min.

[0070] (5) Spin coating method for preparing nickel oxide as a hole transport layer: the remaining CdCl2 on the surface of the cadmium telluride film treated with CdCl2 is washed off, then nickel oxide aqueous solution is spin-coated on the surface, then the sample is annealed on a 200℃ hot stage for 10 min, and finally the annealed sample is treated with 5-10 s of ultraviolet ozone.

[0071] (6) Spin coating of cuprous thiocyanate: spin-coat 3 mg / ml cuprous thiocyanate aqueous ammonia solution on the surface of the nickel oxide and dry, and finally use a hot stage to anneal at 250℃ for 20 min to diffuse copper to the front interface.

[0072] (7) Transparent electrode by magnetron sputtering: the product after annealing is placed in a magnetron sputtering chamber, the gas pressure is stabilized to 0.3-1 Pa, the power is 70 W, the substrate is rotated (25 r / min), and ITO transparent electrode is deposited by sputtering.

[0073] Comparative Example 1

[0074] The difference between the comparative example and Example 1 is that the annealing temperature in step (5) is 200℃, and other steps and parameters are unchanged.

[0075] Comparative Example 2

[0076] The difference between the comparative example and Example 1 is that the annealing and doping treatment in step (5) is not performed, and other steps and parameters are unchanged.

[0077] Figure 7 The spectral response test diagram of the infrared narrow-band photovoltaic device obtained in Example 1 and Comparative Examples 1-2 shows that the infrared narrow-band photovoltaic device obtained in Example 1 has excellent spectral selectivity, the external quantum efficiency tends to 0 below the wavelength of 800 nm, and the half-width is about 20 nm; however, the selectivity of the photovoltaic devices obtained in Comparative Example 1 with insufficient copper diffusion at a lower annealing temperature and Comparative Example 2 without annealing copper diffusion is poor, and has a higher external quantum efficiency below the wavelength of 800 nm.

[0078] The spectral response test of the photovoltaic devices of Example 1 with the active absorption layer of CdTe, Example 2 with the active absorption layer of CdSe 0.23 Te 0.77 , and Example 3 with the active absorption layers of ZnTe and Cd 0.95 Zn 0.05 Te respectively shows that the response wavelength can be adjusted between 560-850 nm by adjusting the active absorption layer. Figure 8

[0079] In summary, the present application performs high-temperature annealing treatment after preparing the cuprous thiocyanate layer, so that the copper is fully diffused to the surface of the FTO glass, the P-type doping concentration of the active absorption layer is improved, resulting in an extremely narrow built-in electric field (<400 nm), the ultraviolet and visible light is absorbed by the neutral region and is difficult to penetrate to the space charge region, resulting in difficulty in being collected by the external circuit; the near-infrared spectrum has a deeper penetration depth and can reach the built-in electric field region, under the action of the built-in electric field, the photo-generated electron / hole pairs can be efficiently separated and transported, thereby realizing the response of the device to narrow spectrum; the active absorption layer uses Cd 1-x Zn x Te or CdSe y Te 1-y ​The x and y values are adjusted to regulate the band gap of the active light-absorbing layer, so as to achieve the purpose of wide-range adjustment of the response wavelength band between 560 nm and 850 nm.

[0080] The present application is described in detail above with reference to the specific embodiments and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that the technical solutions and embodiments of the present application can be variously replaced, modified or improved without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

Claims

1. A method for fabricating an infrared narrowband optoelectronic device, characterized in that, Includes the following steps: S1. After preparing an electron transport layer on FTO glass, prepare an active absorption layer on the electron transport layer. The active absorber layer is made of Cd. 1-x Zn x Te or CdSe y Te 1-y , 0≤x≤1, 0≤y≤1; S2. After treating the active absorber layer with cadmium chloride, prepare a cuprous thiocyanate layer or a nickel oxide layer on the active absorber layer as a hole transport layer. When the hole transport layer is a nickel oxide layer, a cuprous thiocyanate layer is prepared on the hole transport layer. S3. Anneal at 250±5℃ for 10-30 min to diffuse copper to the FTO glass interface; S4. Prepare a transparent electrode on the surface of the cuprous thiocyanate layer.

2. The method for fabricating the infrared narrowband optoelectronic device as described in claim 1, characterized in that, The electron transport layer has a thickness of 30-60 nm, the active absorption layer has a thickness of 1-6 μm, and the hole transport layer has a thickness of 30-60 nm.

3. The method for fabricating the infrared narrowband optoelectronic device as described in claim 1, characterized in that, In S2, the cadmium chloride treatment specifically involves coating the active absorber layer with a cadmium chloride solution and then heat-treating it at 390-420℃ and 600-700 torr for 20-60 minutes.

4. The method for fabricating the infrared narrowband optoelectronic device as described in claim 1, characterized in that, In S1, the electron transport layer is made of cadmium sulfide, tin oxide, or zinc magnesium oxide, and is prepared by radio frequency magnetron sputtering, chemical bath deposition, or spin coating.

5. The method for fabricating the infrared narrowband optoelectronic device as described in claim 1, characterized in that, In S1, the active absorber layer is prepared by near-space sublimation, magnetron sputtering, thermal evaporation or chemical vapor deposition.

6. The method for fabricating the infrared narrowband optoelectronic device as described in claim 1, characterized in that, In S2, the cuprous thiocyanate layer and the nickel oxide layer are prepared by magnetron sputtering or spin coating.

7. The method for fabricating the infrared narrowband optoelectronic device as described in claim 1, characterized in that, In S4, the transparent electrode is made of ITO and is prepared by magnetron sputtering.

8. An infrared narrowband optoelectronic device prepared by the preparation method according to any one of claims 1-7.

9. The infrared narrowband optoelectronic device as described in claim 8, characterized in that, The infrared narrowband optoelectronic device has a spectral half-width of 20±10nm and a photoresponse EQE>30%.

10. The infrared narrowband optoelectronic device as described in claim 8, characterized in that, The infrared narrowband optoelectronic device can achieve a wide range of response band adjustment between 560 and 850 nm by adjusting the band gap of the active absorption layer.

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