ACCZTSe short-wave infrared photoelectric detector based on silver doping and preparation method of ACCZTSe short-wave infrared photoelectric detector

Abstract

The invention relates to the technical field of photoelectric detectors, in particular to an ACCZTSe short-wave infrared photoelectric detector based on silver doping and a preparation method of the ACCZTSe short-wave infrared photoelectric detector based on silver doping, and the detector comprises a substrate, and a molybdenum back electrode, an absorption layer, an n-type layer, a window layer and a surface electrode which are sequentially stacked on the substrate; wherein the absorption layer is an ACCZTSe absorption layer; the material components of the absorption layer comprise six elements of silver, copper, cadmium, zinc, tin and selenium. According to the AgyCu2-yCdxZn1-xSnSe4 detector based on silver doping and the preparation method of the AgyCu2-yCdxZn1-xSnSe4 detector, the concentration of antiposition defects such as CuZn and CuSn can be effectively reduced, carrier recombination is reduced, and the purposes of reducing the dark current of a device and improving the photoelectric conversion efficiency are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of photoelectric detectors, and in particular to a silver-doped ACCZTSe short-wave infrared photoelectric detector and a preparation method thereof. Background Art

[0002] Short-wave infrared photoelectric detectors have good adaptability to working environments and work better than visible light at night and in inclement weather. They are also highly concealed and less susceptible to interference. They are also compact, lightweight, and consume little power. Consequently, infrared detectors have been widely researched and applied in numerous fields.

[0003] The detector material of current commercial short-wave infrared detectors is mainly indium gallium arsenide (InGaAs), which is very sensitive to short-wave infrared light and has the advantages of high detection sensitivity and fast response speed. However, its process requirements are high and the cost is too high, making it difficult to popularize in the civilian field.

[0004] Cu2Cd X Zn (1-X) SnSe4, a novel detector absorption layer material, has an adjustable bandgap, enabling its device to respond over a wavelength range of 400nm to 1700nm. The raw materials are relatively readily available, significantly reducing costs, and the process is relatively simple. However, the growth of this multicomponent compound presents numerous uncontrollable factors, including the coexistence of multiple phases, small grain size, and excessive defects and grain boundaries, leading to poor device performance, high dark current, and a need for improved photoelectric conversion efficiency. Summary of the Invention

[0005] The present invention provides a silver-doped ACCZTSe short-wave infrared photodetector and its preparation method to solve the existing Cu2Cd X Zn (1-X) The technical problems of SnSe4 detector material are large dark current and low photoelectric conversion efficiency.

[0006] In order to solve the above technical problems, in the first aspect, an embodiment of the present application provides a silver-doped ACCZTSe short-wave infrared photodetector, comprising: a substrate and a molybdenum back electrode, an absorption layer, an n-type layer, a window layer and a surface electrode stacked in sequence on the substrate; wherein the absorption layer is an ACCZTSe absorption layer; the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium.

[0007] In some exemplary embodiments, the material of the absorption layer is Ag formed by six elements: silver, copper, cadmium, zinc, tin and selenium. y Cu 2-y Cd x Zn 1-x SnSe4.

[0008] In some exemplary embodiments, the material composition of the absorption layer further includes a NaF source, and the thickness of the NaF source is 25 nm to 35 nm.

[0009] In some exemplary embodiments, the ratio of the silver content in the absorption layer to the total content of the silver and copper elements is between 0.12 and 0.16, and the Ag source temperature is between 890° C. and 920° C.

[0010] In some exemplary embodiments, the absorber layer has a thickness of approximately 1500 nm.

[0011] In some exemplary embodiments, the thickness of the molybdenum back electrode is 500 nm to 1000 nm.

[0012] In a second aspect, an embodiment of the present application also provides a method for preparing a silver-doped ACCZTSe short-wave infrared photodetector, comprising the following steps: first, providing a substrate; then, forming a molybdenum back electrode on the substrate; next, forming an absorption layer on the molybdenum back electrode; wherein the absorption layer is an ACCZTSe absorption layer; the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium; forming an n-type layer on the absorption layer; forming a window layer on the n-type layer; and forming a surface electrode on the window layer.

[0013] In some exemplary embodiments, a molybdenum back electrode is sequentially formed on a substrate, comprising: placing the substrate in a vacuum chamber, first evacuating the chamber to 2.0×10 -3 Pa, introduce 40kPa of argon, adjust the gas pressure to 0.5kPa, start at 120W, pre-sputter for 15 minutes, and then gradually increase to 160W; after the pre-sputtering is completed, introduce 4kPa of oxygen, open the baffle, sputter for 5.5 hours, then take out the sample, soak it in acetone for 15 minutes, then ultrasonicate for 6 minutes, rinse with acetone, put it in anhydrous ethanol and ultrasonicate for 6 minutes, rinse with anhydrous ethanol, blow off the anhydrous ethanol with nitrogen to obtain a molybdenum back electrode.

[0014] In some exemplary embodiments, forming an absorption layer on a molybdenum back electrode includes placing a sample having a molybdenum back electrode in an MBE vacuum coating chamber, and controlling the vacuum range to be 1×10 -5 Pa~1×10 -4 Pa, adjust the temperature of Cu, Cd, Zn, Sn, Se, Ag, and NaF sources, first open the sources except NaF on the sample to co-evaporate and deposit the ACCZTSe absorption layer for 20 minutes, after growing for 6.5 minutes, turn on the NaF source, continue to grow for 11.5 minutes, and turn off the NaF source when the last 2 minutes are left to finally obtain the precursor; after the film deposition is completed, annealing heat treatment is performed to obtain the ACCZTSe absorption layer.

[0015] In some exemplary embodiments, forming an n-type layer on the absorber layer includes: depositing the n-type layer on the absorber layer using a chemical water bath method; rinsing the n-type layer with deionized water, drying the sample surface with N2, and annealing in a 120°C oven for 2 minutes.

[0016] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0017] The embodiment of the present application provides a silver-doped ACCZTSe short-wave infrared photodetector and its preparation method, the detector comprising: a substrate and a molybdenum back electrode, an absorption layer, an n-type layer, a window layer and a surface electrode stacked in sequence on the substrate; wherein the absorption layer is an ACCZTSe absorption layer; the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium. The silver-doped ACCZTSe short-wave infrared photodetector provided in the embodiment of the present application, based on the existing CCZTSe photodetector preparation process, innovatively dopes Ag to replace part of Cu to control the Cu Zn 、Cu Sn The iso-inversion defect and the reduction of carrier recombination reduce the dark current of the photodetector and improve the external quantum efficiency, thereby improving the device performance of the photodetector.

[0018] The silver-doped ACCZTSe short-wave infrared photodetector provided in this application has a spectral response range of 400nm to 1700nm, covering the response bands of both Si and InGaAs. Ag is doped into the CCZTSe material through a co-evaporation growth process, partially replacing Cu with Ag. This reduces the concentration of antisite defects generated by Cu and optimizes its band structure, thereby reducing the device's dark current and improving photoelectric conversion efficiency. The method for preparing the short-wave infrared detector provided in this application features a simple process, controllable process, good repeatability, low cost, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0020] Figure 1 This is a schematic structural diagram of a silver-doped ACCZTSe short-wave infrared photodetector provided in an embodiment of the present application.

[0021] Figure 2 A schematic flow chart of a method for preparing a silver-doped ACCZTSe short-wave infrared photodetector provided in an embodiment of the present application.

[0022] Figure 3This is an IV curve diagram of the silver-doped ACCZTSe short-wave infrared photodetector provided in an embodiment of the present application.

[0023] Figure 4 This is a diagram of the external quantum efficiency of the silver-doped ACCZTSe short-wave infrared photodetector provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] As can be seen from the background technology, the existing Cu2Cd X Zn (1-X) The technical problems of SnSe4 detector material are large dark current and low photoelectric conversion efficiency.

[0025] In order to solve the above technical problems, the embodiment of the present application provides a silver-doped ACCZTSe short-wave infrared photodetector and its preparation method, the detector includes: a substrate and a molybdenum back electrode, an absorption layer, an n-type layer, a window layer and a surface electrode stacked in sequence on the substrate; wherein the absorption layer is an ACCZTSe absorption layer; the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium. The silver-doped ACCZTSe short-wave infrared photodetector and its preparation method provided by the present application solve the existing Cu2Cd X Zn (1-X) The technical problems of SnSe4 detector material are large dark current and low photoelectric conversion efficiency.

[0026] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0027] See Figure 1 The embodiment of the present application provides a silver-doped ACCZTSe short-wave infrared photodetector, comprising: a substrate 100 and a molybdenum back electrode 101, an absorption layer 102, an n-type layer 103, a window layer 104, and a surface electrode 105 sequentially stacked on the substrate 100; wherein the absorption layer 102 is an ACCZTSe absorption layer; the material composition of the absorption layer 102 includes six elements: silver, copper, cadmium, zinc, tin, and selenium; and the surface electrode 105 is arranged on the side of the window layer 104 away from the n-type layer 103.

[0028] In some embodiments, the material of the absorption layer 102 is Ag formed by six elements: silver, copper, cadmium, zinc, tin and selenium. y Cu 2-y Cd x Zn 1-xSnSe4.

[0029] In some embodiments, the material composition of the absorption layer 102 further includes a NaF source, and the thickness of the NaF source is 25 nm to 35 nm. For example, the thickness of the NaF source can be 25 nm, 28 nm, 30 nm, 32 nm, or 35 nm. In the actual preparation process, the thickness of the NaF source is set according to actual conditions.

[0030] In some embodiments, the ratio of the silver content in the absorption layer 102 to the total content of the silver and copper elements is between 0.12 and 0.16, that is, the range of Ag / (Ag+Cu) is between 0.12 and 0.16; the Ag source temperature is 890°C to 920°C.

[0031] In some embodiments, the absorber layer 102 has a thickness of about 1500 nm.

[0032] In some embodiments, the thickness of the molybdenum back electrode 101 is 500 nm to 1000 nm. For example, the thickness of the molybdenum back electrode 101 can be 500 nm, 800 nm, or 1000 nm. In the actual preparation process, the corresponding thickness is set according to the actual situation.

[0033] The material of the n-type layer 103 includes at least one of cadmium sulfide, zinc sulfide, and zinc oxide, but the present invention is not limited thereto.

[0034] In some embodiments, the thickness of the n-type layer 103 is 50 nm to 100 nm. For example, the thickness of the n-type layer 103 can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm. During the preparation process, the thickness can be set according to actual conditions.

[0035] In some embodiments, the window layer 104 is a transparent conductive window layer, and its material includes at least one of aluminum zinc oxide, indium tin oxide, and indium zinc oxide, but the present invention is not limited thereto.

[0036] In some embodiments, the material of the surface electrode 105 includes at least one of copper, aluminum, silver, and gold, but is not limited thereto.

[0037] In some embodiments, the short-wave infrared photodetector prepared in the present application absorbs light in the wavelength range of 400 nm to 1700 nm.

[0038] An embodiment of the present application also provides a method for preparing a silver-doped ACCZTSe short-wave infrared photodetector, comprising the following steps: first, providing a substrate; then, forming a molybdenum back electrode on the substrate; next, forming an absorption layer on the molybdenum back electrode; wherein the absorption layer is an ACCZTSe absorption layer; the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium; forming an n-type layer on the absorption layer; forming a window layer on the n-type layer; and forming a surface electrode on the window layer.

[0039] In some embodiments, a molybdenum back electrode is sequentially formed on a substrate, comprising: placing the substrate in a vacuum chamber, first evacuating the chamber to 2.0×10 -3 Pa, introduce 40kPa of argon, adjust the gas pressure to 0.5kPa, start at 120W, pre-sputter for 15 minutes, and then gradually increase to 160W; after the pre-sputtering is completed, introduce 4kPa of oxygen, open the baffle, sputter for 5.5 hours, then take out the sample, soak it in acetone for 15 minutes, then ultrasonicate for 6 minutes, rinse with acetone, put it in anhydrous ethanol and ultrasonicate for 6 minutes, rinse with anhydrous ethanol, blow off the anhydrous ethanol with nitrogen to obtain a molybdenum back electrode.

[0040] In some embodiments, forming an absorption layer on a molybdenum back electrode includes placing a sample having a molybdenum back electrode in an MBE vacuum coating chamber, and controlling the vacuum range to be 1×10 -5 Pa~1×10 -4 Pa, the temperature of Cu, Cd, Zn, Sn, Se, Ag, and NaF sources were adjusted. The ACCZTSe absorption layer was first deposited on the sample by co-evaporation with sources other than NaF for 20 minutes. After 6.5 minutes of growth, the NaF source was turned on and continued to grow for 11.5 minutes (NaF was about 30nm long). When the last 2 minutes were left, the NaF source was turned off to finally obtain the precursor. After the film deposition was completed, annealing heat treatment was performed to obtain the ACCZTSe absorption layer. It should be noted that by adjusting the different temperatures of the Ag source, different precursor samples with Ag / (Ag+Cu) ratios of 0.12 to 0.16 were obtained.

[0041] In some embodiments, the step of annealing the precursor to obtain the ACCZTSe absorption layer specifically includes the following steps: placing the above-mentioned precursor into an annealing furnace, placing the precursor in the annealing furnace, and introducing 2.5kPaH2Se and 50kPaN2 after evacuating the air. In the first stage, heating from 25°C to 310°C for 15min, and annealing at 310°C for 60min with 5% hydrogen selenide; in the second stage, heating from 310°C to 420°C for 15min, and annealing at 420°C for 60min with 5% hydrogen selenide; then cooling and evacuating the gas when cooling to 300°C, and waiting for cooling to be completed to obtain the ACCZTSe absorption layer.

[0042] In some embodiments, forming an n-type layer on the absorber layer includes: depositing the n-type layer on the absorber layer using a chemical water bath method; rinsing the n-type layer with deionized water, drying the sample surface with N2, and annealing in a 120°C oven for 2 minutes.

[0043] Figure 2 FIG1 is a flow chart of a method for manufacturing an ACCZTSe short-wave infrared photodetector according to an embodiment of the present invention, which includes the following steps S110 to S180 , and the implementation of each step is described in detail below.

[0044] In the following specific examples, the n-type layer is a CdS buffer layer, the window layer is an intrinsic zinc oxide / Al-doped zinc oxide window layer, and the surface electrode is a Ni / Al / Ni electrode. A molybdenum layer is deposited on a silicon wafer by magnetron sputtering to form a molybdenum back electrode. The CdS buffer layer is grown in a chemical bath. The intrinsic zinc oxide / Al-doped zinc oxide window layer is grown by magnetron sputtering. The Ni / Al / Ni electrode is formed using electron beam evaporation.

[0045] In step S110 , the silicon wafer substrate is first cleaned.

[0046] Specifically, prepare a 4-inch silicon wafer, ultrasonicate it with acetone, ethanol, and deionized water for 3 minutes respectively, then soak it in 2% hydrofluoric acid in a fume hood for 1 hour, and then observe whether there is any residual water on the surface of the silicon wafer. It is best if the water droplets slide down due to gravity without any residue. Finally, ultrasonicate it with deionized water and ethanol for 3 minutes respectively, and blow it dry.

[0047] In step S120 , the clean silicon wafer substrate is patterned.

[0048] Specifically, a cleaned silicon wafer is placed on the spin coater turntable, a negative photoresist is applied to the wafer, the spin coater is turned on, and the negative photoresist is evenly applied. After spin coating, a pre-bake treatment is performed for 30 seconds. After baking, the sample is exposed to ultraviolet light under the photolithography machine for 20 seconds, followed by a post-bake treatment for 60 seconds. The sample is then placed in a developer for 20 seconds, followed by an etchant for 30 seconds. Finally, the sample is placed in an acetone solution to remove the negative photoresist, ultimately obtaining a grid patterned structure. The patterned silicon wafer is then immersed in a strong acid solution to remove the oxide layer on the surface of the silicon wafer.

[0049] In step S130, a Mo back electrode is plated on the patterned silicon wafer.

[0050] The specific operation is as follows: Place the patterned silicon wafer in a vacuum chamber and pump the air to 2.0×10 -3Pa, pass 40kPa of argon, adjust the gas pressure to 0.5kPa, ignite at 120W, pre-sputter for 15 minutes, gradually increase to 160w during the period, pass 4kPa of oxygen after pre-sputtering, open the baffle, sputter for 5.5 hours, then take it out, soak it in acetone for 15 minutes, then ultrasonicate for 6 minutes, rinse with acetone, put it in anhydrous ethanol for 6 minutes, rinse with anhydrous ethanol, blow off the anhydrous ethanol with nitrogen, and a Mo back electrode with a thickness of 800nm ​​is obtained.

[0051] In step S140 , an absorption layer is grown on the Mo back electrode.

[0052] Specifically, the multi-source co-evaporation growth method was used to prepare ACCZTSe precursors with four different Ag / (Ag+Cu) ratios, namely 0 (undoped control group), 0.12, 0.14, and 0.16. After the sample with Mo back electrode was placed in the MBE vacuum coating chamber, the vacuum range was controlled at 1×10 -5 Pa~1×10 -4 Pa, first open the source except NaF on the sample to co-evaporate and deposit the ACCZTSe absorption layer for 20 minutes. After growing for 6.5 minutes, open the NaF source and continue to grow for 11.5 minutes (NaF is about 30nm long). When the last 2 minutes are left, turn off the NaF source. Adjust and fix the temperatures of Cu, Cd, Zn, Sn, and Se sources to 1188℃, 272℃, 350℃, 1174℃, and 259℃ respectively. By adjusting the different temperatures of the Ag source to 896℃, 903℃, and 910℃ respectively, different precursor samples with silver content and silver plus copper content ratio Ag / (Ag+Cu) of 0.12, 0.14, and 0.16 were obtained; by turning off the Ag source and following the same procedure as above, an undoped precursor sample was obtained.

[0053] After obtaining the precursor, the precursors with silver element content and silver plus copper element content ratios Ag / (Ag+Cu) of 0, 0.12, 0.14, and 0.16, respectively, were placed in an annealing furnace. After the air was evacuated, 2.5kPa H2Se and 50kPaN2 were introduced. In the first stage, the precursors were heated from 25°C to 310°C for 15min, and annealed at 310°C for 60min with 5% hydrogen selenide; in the second stage, the precursors were heated from 310°C to 420°C for 15min, and annealed at 420°C for 60min with 5% hydrogen selenide; then the temperature was lowered and the gas was evacuated when it was cooled to 300°C, and the ACCZTSe absorption layer was obtained after cooling was completed.

[0054] In step S150 , CdS (n-type layer) is deposited on the ACCZTSe absorption layer using a chemical water bath method.

[0055] Specifically, the prepared reaction solution was poured into the center of a glass container and stirred evenly. The reaction temperature was controlled at 67.5°C and the growth time was 9.5 minutes, depositing an n-type layer approximately 50 nm thick on the absorber layer. After the n-type layer was deposited, it was rinsed with deionized water, dried with nitrogen, and placed in a 120°C constant temperature oven for 2 minutes.

[0056] In step S160, an i-ZnO / AZO window layer is magnetron sputtered on the n-type layer.

[0057] The specific operation is to place the obtained sample in a vacuum i-ZnO / AZO sputtering chamber, introduce Ar and O2, start i-ZnO at 120W, sputter for 4 rounds, adjust the power to 220W, sputter for 4 rounds, and then adjust the power to 350W for 16 rounds; turn off O2, introduce H2, start AZO at 120W, pre-sputter at 500W for 15 minutes, and sputter for 10 rounds at 500W to obtain a window layer i-ZnO / AZO.

[0058] In step S170, a Ni / Al / Ni electrode is formed on the window layer.

[0059] The specific operation is to move the above samples into the electron beam coating chamber and control the vacuum range to 1×10 -3 Pa~1×10 -2 Pa, a surface electrode was prepared on the transparent conductive window layer by high vacuum thermal evaporation, and Ni / Al / Ni surface electrodes were uniformly evaporated in sequence according to the pattern through a mask with an electrode pattern. The first layer of Ni had a thickness of 100nm, the Al had a thickness of 1000nm, and the last layer of Ni had a thickness of 100nm, resulting in a surface electrode with a thickness of about 1000nm.

[0060] In step S180, the device is finally divided into a device array by wet photolithography.

[0061] The specific operation is as follows: the surface of the above-grown functional layer is spin-coated with negative photoresist, pre-baked for 20 seconds, exposed, post-baked for 60 seconds, developed for 20 seconds, etched with hydrochloric acid solution for 40 seconds, and then de-bonded with acetone to form multiple devices on a four-inch silicon wafer. The device size is 2.5mm×2.5mm.

[0062] Figure 3 The IV curves of the ACCZTSe short-wave infrared photodetectors with different Ag / (Ag+Cu) ratios produced in the above specific embodiments are shown in FIG. Figure 4The corresponding external quantum efficiency graph is shown below. The results show that the silver-doped device has lower dark current than the undoped device and higher external quantum efficiency than the undoped device. Specifically, the device with a silver content and a silver-to-copper ratio (Ag / (Ag+Cu)) of 0.12 significantly reduces dark current, achieves the highest external quantum efficiency (approximately 85%), and achieves the best performance.

[0063] Based on the above technical solution, the embodiment of the present application provides a silver-doped ACCZTSe short-wave infrared photodetector and its preparation method, the detector includes: a substrate and a molybdenum back electrode, an absorption layer, an n-type layer and a window layer stacked in sequence on the substrate; wherein the absorption layer is an ACCZTSe absorption layer; the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium. The silver-doped ACCZTSe short-wave infrared photodetector provided in the embodiment of the present application, based on the existing preparation process of CCZTSe photodetector, innovatively dopes Ag to replace part of Cu to control the Cu Zn 、Cu Sn The iso-inversion defect and the reduction of carrier recombination reduce the dark current of the photodetector and improve the external quantum efficiency, thereby improving the device performance of the photodetector.

[0064] The silver-doped ACCZTSe short-wave infrared photodetector provided in this application has a spectral response range of 400nm to 1700nm, covering the response bands of both Si and InGaAs. Ag is doped into the CCZTSe material through a co-evaporation growth process, partially replacing Cu with Ag. This reduces the concentration of antisite defects generated by Cu and optimizes its band structure, thereby reducing the device's dark current and improving photoelectric conversion efficiency. The method for preparing the short-wave infrared detector provided in this application features a simple process, controllable process, good repeatability, low cost, and is suitable for large-scale production.

[0065] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A silver-doped ACCZTSe short-wave infrared photodetector, characterized in that: include: A substrate and a molybdenum back electrode, an absorption layer, an n-type layer, a window layer and a surface electrode sequentially stacked on the substrate; wherein, The absorption layer is an ACCZTSe absorption layer; the material components of the absorption layer include six elements: silver, copper, cadmium, zinc, tin and selenium.

2. The silver-doped ACCZTSe short-wave infrared photodetector according to claim 1, characterized in that: The material of the absorption layer is Ag formed by six elements: silver, copper, cadmium, zinc, tin and selenium. y Cu 2-y Cd x Zn 1-x SnSe4.

3. The silver-doped ACCZTSe short-wave infrared photodetector according to claim 1, characterized in that: The material composition of the absorption layer also includes a NaF source, and the thickness of the NaF source is 25nm to 35nm.

4. The silver-doped ACCZTSe short-wave infrared photodetector according to claim 1, characterized in that: The ratio of the silver content in the absorption layer to the total content of the silver and copper elements is between 0.12 and 0.16, and the Ag source temperature is between 890° C. and 920° C.

5. The silver-doped ACCZTSe short-wave infrared photodetector according to claim 1, characterized in that: The thickness of the absorption layer is about 1500 nm.

6. The silver-doped ACCZTSe short-wave infrared photodetector according to claim 1, characterized in that: The thickness of the molybdenum back electrode is 500nm-1000nm.

7. A method for preparing a silver-doped ACCZTSe short-wave infrared photodetector, characterized in that: The following steps are involved: providing a substrate; forming a molybdenum back electrode on the substrate; An absorption layer is formed on the molybdenum back electrode; wherein the absorption layer is an ACCZTSe absorption layer; and the material composition of the absorption layer includes six elements: silver, copper, cadmium, zinc, tin and selenium; forming an n-type layer on the absorption layer; forming a window layer on the n-type layer; A surface electrode is formed on the window layer.

8. The method for preparing the silver-doped ACCZTSe short-wave infrared photodetector according to claim 7, characterized in that: A molybdenum back electrode is sequentially formed on the substrate, comprising: The substrate was placed in a vacuum chamber and the pressure was first pumped down to 2.0 × 10 -3 Pa, introduce 40kPa of argon, adjust the gas pressure to 0.5kPa, start at 120W, pre-sputter for 15 minutes, and then gradually increase to 160W; after the pre-sputtering is completed, introduce 4kPa of oxygen, open the baffle, sputter for 5.5 hours, then take out the sample, soak it in acetone for 15 minutes, then ultrasonicate for 6 minutes, rinse with acetone, put it in anhydrous ethanol and ultrasonicate for 6 minutes, rinse with anhydrous ethanol, blow off the anhydrous ethanol with nitrogen to obtain a molybdenum back electrode.

9. The method for preparing the silver-doped ACCZTSe short-wave infrared photodetector according to claim 7, characterized in that: An absorption layer is formed on the molybdenum back electrode, comprising: The sample with Mo back electrode was placed in MBE vacuum coating chamber and the vacuum range was controlled at 1×10 -5 Pa~1×10 - 4 Pa, adjust the temperature of Cu, Cd, Zn, Sn, Se, Ag, and NaF sources, first open the sources except NaF on the sample to co-evaporate and deposit the ACCZTSe absorption layer for 20 minutes, after growing for 6.5 minutes, turn on the NaF source, continue to grow for 11.5 minutes, and turn off the NaF source when the last 2 minutes are left to finally obtain the precursor; after the film deposition is completed, annealing heat treatment is performed to obtain the ACCZTSe absorption layer.

10. The method for preparing the silver-doped ACCZTSe short-wave infrared photodetector according to claim 9, characterized in that: forming an n-type layer on the absorption layer, comprising: depositing an n-type layer on the absorber layer by a chemical water bath method; The n-type layer was rinsed with deionized water, and the sample surface was dried with N2, and then annealed in an oven at 120°C for 2 minutes.

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