Method for the preparation of a patterned substrate with a selective growth of a lead sulfide thin film on the surface

Abstract

The application discloses a preparation method of a surface selective growth of a lead sulfide film on a patterned substrate, and comprises the following steps: 1) surface modification of the patterned substrate in an oxidizing agent solution; 2) spin coating photoresist on the surface of the patterned substrate, no-mask exposure and photoresist removal, and the cycle is repeated for multiple times; and 3) the surface pretreated patterned substrate is put into a precursor solution for growing the lead sulfide film, and a chemical deposition reaction is carried out, and the method is completed. According to the preparation method, the lead sulfide film can be selectively grown on the substrate containing metal patterns through simple treatment of the substrate surface, without changing the proportion or conditions of the deposition solution, and the complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process are avoided; the preparation method overcomes the defect that the chemical water bath method for growing the lead sulfide film can only grow the film on the whole piece at the same time, greatly simplifies the technological process, and improves the success rate and yield of the detector preparation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of photoelectric detection, and particularly relates to a preparation method of selective growth of a lead sulfide film on a surface of a patterned substrate. BACKGROUND

[0002] Lead sulfide is a group IV-VI direct band gap semiconductor material, and is one of the earliest infrared detector materials, which is widely used in the field of infrared detection due to its high sensitivity in short-wave infrared, low Auger noise and room temperature operation. There are many preparation methods of lead sulfide film, for example, the preparation method includes electrochemical deposition method, microwave heating method, chemical vapor deposition method, and chemical water bath deposition method. Among them, the chemical water bath method is widely concerned because of its easy manufacturing, low cost, no need for complex equipment, and the ability to deposit thin films on different substrates. Moreover, the lead sulfide film synthesized by the chemical water bath method is compatible with the CMOS semiconductor process, which is conducive to realizing low-cost and high-performance area array detectors.

[0003] The chemical bath deposition method is a method for growing lead sulfide film based on a solution atmosphere, which includes two stages of nucleation and particle growth. Although the growth rate and film thickness can be controlled by adjusting the ratio of the deposition solution or the deposition environment and conditions to realize uniform growth of the film on the whole substrate. However, in the preparation process of large-area lead sulfide detector, the substrate usually includes different materials, such as electrodes and insulating substrates. The prior art usually grows the film directly on the surface of the whole substrate, and cannot selectively grow the film material on part of the material, so that after the film is grown, a complex etching process needs to be carried out in the whole manufacturing process of the detector, and in this process, over-etching or incomplete etching often occurs, resulting in complex manufacturing process of the detector, low yield, and great influence on the performance of the detector.

[0004] If a method can be found to selectively grow lead sulfide film material based on chemical water bath deposition method on a metal-containing patterned substrate, then the growth of lead sulfide film can be controlled only in the photosensitive area, and there is no need for very complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process, which is of great significance for preparing large-area lead sulfide detectors with excellent performance. SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the related art. To this end, the main purpose of the present application is to provide a preparation method of selective growth of a lead sulfide film on a surface of a patterned substrate, which realizes selective growth of a lead sulfide film on the surface of a Si / SiO2 substrate and a metal layer, can control the growth of the lead sulfide film only in the photosensitive area, thereby simplifying a variety of complex and expensive processes in the subsequent chip manufacturing process, and can be widely applied to the preparation of various lead sulfide-based area array detectors.

[0006] The object of the present application is achieved by the following technical solutions.

[0007] The application discloses a preparation method of a surface-selective growth of a lead sulfide film on a patterned substrate.

[0008] 1) The patterned substrate is placed in an oxidizing agent solution for surface modification to obtain a surface-modified patterned substrate.

[0009] 2) Photoresist is spin-coated on the surface of the patterned substrate, and no mask exposure and photoresist stripping are performed for multiple cycles to obtain a surface-preprocessed patterned substrate.

[0010] 3) The surface-preprocessed patterned substrate obtained in step 2) is placed in a precursor solution for growing a lead sulfide film to perform a chemical deposition reaction, so as to obtain a surface-selective growth of a lead sulfide film material on the patterned substrate.

[0011] In step 1), the surface modification time is 2-3 min. In this step, the surface modification time should be strictly controlled to avoid excessive damage to the Si / SiO2 substrate. The surface modification can change the hydrophilic property of the Si / SiO2 substrate, thereby affecting the quality of the lead sulfide film grown by the chemical water bath. Further, the surface modification in this step plays a very important role in the photoelectric performance of the lead sulfide photoactive film prepared by the subsequent chemical deposition method.

[0012] In some specific embodiments, the patterned substrate is obtained by the following preparation method: 5-15 nm of chromium and 50-150 nm of gold are deposited on the surface of the Si / SiO2 substrate by a magnetron sputtering method, and then a metal layer is left in the local area of the Si / SiO2 substrate by using a photolithography stripping process, so as to obtain the patterned substrate.

[0013] In some specific embodiments, the Si / SiO2 substrate in the preparation process of the patterned substrate is further pretreated, specifically: the Si / SiO2 substrate is ultrasonically cleaned with deionized water, acetone and alcohol for 5-15 min, respectively, and then dried with nitrogen for standby use.

[0014] In some specific embodiments, the oxidizing agent is a mixture of hydrogen peroxide and concentrated sulfuric acid with a mass ratio of 7:3.

[0015] In some specific embodiments, the photoresist in step 2) is spin-coated on the surface of the patterned substrate, specifically: two layers of photoresist are spin-coated on the surface of the patterned substrate, the first layer of photoresist is stripping glue, and the second layer of photoresist is ultraviolet glue.

[0016] The step can affect the wettability of the surface of the metal layer and change the contact angle of the surface of the metal layer by spin-coating two layers of photoresist on the surface of the graphic substrate, so that the surface of the metal layer presents certain hydrophobicity, the nucleation probability of the lead sulfide film grown by the water bath method on the surface of the metal layer is greatly reduced, and the growth of the lead sulfide film is inhibited.

[0017] In some embodiments, the coating conditions of the first layer of photoresist are as follows: the spin-coating speed is 500-4000 rpm, and after spin-coating, the photoresist is placed on a hot plate at 170 DEG C for drying for 10 minutes; the coating conditions of the second layer of stripping glue are as follows: the spin-coating speed is 500-5000 rpm, and then the stripping glue is placed on a hot plate at 100 DEG C for drying for 10 minutes, which can change the nucleation probability and growth speed of the lead sulfide film on the surface of the metal layer.

[0018] In some embodiments, the conditions of the maskless exposure in step 2) are as follows: the exposure time is 8-20 s; and the stripping is specifically as follows: the exposed graphic substrate is soaked in an acetone solution for 10 minutes, and then soaked in an AZ300 solution for 1-3 minutes, and in this step, the soaking time should be strictly controlled to avoid damage to the substrate.

[0019] In some embodiments, the temperature of the acetone solution is 40-60 DEG C.

[0020] In some embodiments, the precursor solution for growing the lead sulfide film is prepared by the following configuration method:

[0021] In some embodiments, lead acetate is configured into a solution A with a concentration of 0.01-1 mol / L; sodium hydroxide is configured into a solution B with a concentration of 0.1-10 mol / L; thiourea is configured into a solution C with a concentration of 0.01-1 mol / L; and sodium citrate is configured into a solution D with a concentration of 0.01-1 mol / L; and the solution A, the solution B, the solution C and the solution D are mixed in the order of ABCD to configure the precursor solution for growing the lead sulfide film.

[0022] In step 4), the thickness of the lead sulfide film can be controlled by controlling the deposition time and temperature, and the uniformity of the thickness of the lead sulfide film can be controlled by controlling the included angle between the soaking part and the liquid surface.

[0023] Further, in step 4), the conditions of the chemical deposition are as follows: the deposition temperature is 40-60 DEG C, the deposition time is 0.5-2 h, and the included angle with the liquid surface is 65-75 DEG.

[0024] Compared with the prior art, the present application has at least the following advantages:

[0025] 1) The preparation method provided by the application first performs surface modification on the patterned substrate by using an oxidizing agent, changes the hydrophilic property of the Si / SiO2 substrate, and then affects the quality of the lead sulfide film grown by chemical water bath; then two layers of photoresist are spin-coated on the surface of the patterned substrate, the wettability of the metal layer surface in the patterned substrate is improved, and the contact angle of the metal layer surface is changed, that is, the affinity of the metal layer surface to water is reduced, so that the metal layer surface presents a certain hydrophobicity, thereby making the nucleation probability and growth rate of the lead sulfide on the surface of the Si / SiO2 substrate and the metal layer in the patterned substrate different, and the purpose of selectively growing the lead sulfide film on the substrate containing the metal pattern is achieved, and the lead sulfide film can be accurately covered on the photosensitive area outside the metal electrode;

[0026] 2) The preparation method provided by the application can achieve the purpose of selectively growing the lead sulfide film on the substrate containing the metal pattern only by simple treatment of the surface of the substrate, without changing the ratio of the deposition solution or the deposition environment and conditions, and avoiding complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process; the preparation method overcomes the defect that the lead sulfide film can only be grown on the whole piece at the same time when the chemical water bath method is used to grow the lead sulfide film, greatly simplifies the process flow, and improves the success rate and yield of the detector preparation. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the application, the drawings required to be used in the specific embodiments or prior art description will be briefly introduced below.

[0028] Figure 1 The surface morphology diagram (microscope measurement) of the lead sulfide film material deposited on the patterned substrate by chemical water bath for Comparative Example 1, wherein the square area is the gold substrate area, and the rest is the SiO2 substrate;

[0029] Figure 2 The surface morphology diagram (SEM measurement) of the lead sulfide film material deposited on the patterned substrate by chemical water bath for Comparative Example 1, wherein (a) is the surface morphology of the lead sulfide film grown on the metal, and (b) is the surface morphology of the lead sulfide film grown on the SiO2;

[0030] Figure 3 The process flow diagram of the preparation method of the surface selective growth of the lead sulfide film on the patterned substrate provided by the application;

[0031] Figure 4 The surface morphology diagram (microscope measurement) of the surface selective growth of the lead sulfide film on the patterned substrate obtained in Example 2 of the application, wherein the square area is the gold substrate area, and the rest is the SiO2 substrate;

[0032] Figure 5 The surface topography of the selectively grown lead sulfide thin film on the surface of the patterned substrate obtained in Example 2 is shown in (a) and (b), wherein (a) is the surface topography of the lead sulfide thin film grown on the metal, and (b) is the surface topography of the lead sulfide thin film grown on the SiO2. DETAILED DESCRIPTION

[0033] The application will be further described in the following detailed description with reference to the drawings and examples, which are described for illustrative purposes only and are not intended to limit the scope of the application.

[0034] When a range, preferably range, or preferred upper and lower limits of a value are expressed as a range, it is understood that any and every subrange between the upper and lower limits of that range is specifically contemplated, regardless of whether that subrange is explicitly disclosed. Unless otherwise indicated, numerical ranges are inclusive of the recited endpoints and all integer and fractions within that range.

[0035] All percentages, parts by weight, ratios, and other values are based on weight, unless otherwise specified.

[0036] The materials, methods, and examples provided herein are illustrative only and, unless otherwise indicated, are not intended to be limiting.

[0037] In the following examples, the index of the photoresist LOR raw material is Microchem LOR5A photoresist, which is specifically purchased from Xi'an Boyan Micro-nano Information Technology Co., Ltd.

[0038] The index of the photoresist S1805 raw material is DOW / Shipley S1805 photoresist, which is specifically purchased from Xi'an Boyan Micro-nano Information Technology Co., Ltd.

[0039] Example 1

[0040] This example provides a preparation method of selectively growing a lead sulfide thin film on the surface of a patterned substrate, the process flow thereof is shown in Figure 3 The preparation method comprises the following steps:

[0041] 1) Pretreatment of Si / SiO2 substrate

[0042] The Si / SiO2 substrate was ultrasonically cleaned with deionized water, acetone and alcohol for 10 minutes respectively, and then dried with nitrogen for standby;

[0043] 2) Preparation of patterned substrate

[0044] The Si / SiO2 substrate surface pretreated in step 1) is deposited with 10 nm chromium and 100 nm gold by a magnetron sputtering method, and then a metal layer is left on a local area of the substrate by using a photolithography stripping process to obtain a patterned substrate;

[0045] 3) Surface pretreatment of the patterned substrate

[0046] 31) The patterned substrate obtained in step 2) is soaked in a mixed solution of hydrogen peroxide and concentrated sulfuric acid with a mass ratio of 7:3 for 2 min, then washed with deionized water and dried with nitrogen to obtain a patterned substrate with a surface modified;

[0047] 32) Two layers of photoresist are spin-coated on the surface of the patterned substrate with a surface modified, the first layer of photoresist is a stripping glue (LOR) with a spin-coating speed of 1500 rpm, and after spin-coating, the substrate is placed on a hot plate at 170℃ for 10 min for drying; the second layer of photoresist is a UV glue (AZ1500) with a spin-coating speed of 1000 rpm, and after spin-coating, the substrate is placed on a hot plate at 100℃ for 10 min for drying to obtain a patterned substrate coated with glue;

[0048] 33) The surface of the patterned substrate coated with glue is subjected to maskless exposure with an exposure time of 10 s;

[0049] 34) The exposed patterned substrate is soaked in an acetone solution at a constant temperature of 50℃ for 10 min, and then soaked in an AZ300 solution for 3 min; the steps 31) to 34) are cycled twice;

[0050] 4) Preparation of precursor solution

[0051] Lead acetate is configured into a solution A with a concentration of 0.20 mol / L, sodium hydroxide is configured into a solution B with a concentration of 0.5 mol / L, thiourea is configured into a solution C with a concentration of 0.15 mol / L, and sodium citrate is configured into a solution D with a concentration of 0.15 mol / L; then, the solutions A-D are mixed in the order of ABCD to configure a precursor solution;

[0052] 5) Deposition of lead sulfide film

[0053] The patterned substrate with a surface pretreated in step 3) is placed into the precursor solution in step 4), the water bath temperature is kept at 60℃, the deposition time is 0.5 h, and the included angle with the liquid surface is 75°, thereby obtaining a patterned substrate with a surface selectively grown lead sulfide film.

[0054] Example 2

[0055] The present embodiment provides a preparation method of a patterned substrate with a surface selectively grown lead sulfide film, which comprises the following steps:

[0056] 1) Pretreatment of Si / SiO2 substrate

[0057] The Si / SiO2 substrate was ultrasonically cleaned with deionized water, acetone and alcohol for 10 min, respectively, and then dried with nitrogen;

[0058] 2) Preparation of the patterned substrate

[0059] The Si / SiO2 substrate pretreated in step 1) was deposited with 10 nm chromium and 100 nm gold by magnetron sputtering, and then a metal layer was left on a local area of the substrate by using a photoresist stripping process to obtain a patterned substrate;

[0060] 3) Surface pretreatment of the patterned substrate

[0061] 31) The patterned substrate obtained in step 2) was immersed in a mixed solution of hydrogen peroxide and concentrated sulfuric acid with a mass ratio of 7:3 for 2 min, then washed with deionized water and dried with nitrogen to obtain a patterned substrate with a modified surface;

[0062] 32) Two layers of photoresist were spin-coated on the surface of the patterned substrate with a modified surface, the first layer of photoresist was a stripping resist (LOR) with a spin-coating speed of 4000 rpm, and after spin-coating, the substrate was placed on a hot plate at 170°C for 10 min for drying; the second layer of photoresist was an ultraviolet resist (AZ1500) with a spin-coating speed of 3000 rpm, and after spin-coating, the substrate was placed on a hot plate at 100°C for 10 min for drying to obtain a patterned substrate coated with photoresist;

[0063] 33) The surface of the patterned substrate coated with photoresist was subjected to maskless exposure with an exposure time of 15 s;

[0064] 34) The exposed patterned substrate was immersed in an acetone solution at a constant temperature of 50°C for 10 min, and then immersed in an AZ300 solution for 3 min; the steps 31) to 34) were repeated twice;

[0065] 4) Preparation of the precursor solution

[0066] Lead acetate was prepared into a solution A with a concentration of 0.40 mol / L, sodium hydroxide was prepared into a solution B with a concentration of 1.14 mol / L, thiourea was prepared into a solution C with a concentration of 0.3 mol / L, and sodium citrate was prepared into a solution D with a concentration of 0.3 mol / L; then, the solutions A-D were mixed in the order of ABCD to prepare a precursor solution;

[0067] 5) Deposition of lead sulfide film

[0068] The patterned substrate with a surface pretreated in step 3) was placed into the precursor solution in step 4), the water bath temperature was kept at 40°C, the deposition time was 2 h, and the included angle with the liquid surface was 70°, thereby obtaining a patterned substrate with a surface selectively grown lead sulfide film.

[0069] Example 3

[0070] The present embodiment provides a method for preparing a surface of a patterned substrate selectively growing a lead sulfide film, which comprises the following steps:

[0071] 1) Pretreatment of Si / SiO2 substrate

[0072] The Si / SiO2 substrate was ultrasonically cleaned with deionized water, acetone and alcohol respectively for 10 min, and then dried with nitrogen for standby;

[0073] 2) Preparation of patterned substrate

[0074] The Si / SiO2 substrate pretreated in step 1) was deposited with 10 nm chromium and 100 nm gold by magnetron sputtering, and then a metal layer was left in a local area of the substrate by using a photoresist stripping process to obtain a patterned substrate;

[0075] 3) Surface pretreatment of patterned substrate

[0076] 31) The patterned substrate obtained in step 2) was immersed in a mixed solution of hydrogen peroxide and concentrated sulfuric acid with a mass ratio of 7:3 for 2 min, then washed with deionized water and dried with nitrogen to obtain a patterned substrate with a modified surface;

[0077] 32) Two layers of photoresist were spin-coated on the surface of the patterned substrate with a modified surface, the first layer of photoresist was a stripping resist (LOR) with a spin-coating speed of 3000 rpm, and after spin-coating, it was placed on a hot plate at 170°C for 10 min for drying; the second layer of photoresist was an ultraviolet resist (AZ1500) with a spin-coating speed of 5000 rpm, and after spin-coating, it was placed on a hot plate at 100°C for 10 min for drying to obtain a patterned substrate coated with photoresist;

[0078] 33) The surface of the patterned substrate coated with photoresist was subjected to maskless exposure with an exposure time of 20 s;

[0079] 34) The exposed patterned substrate was immersed in an acetone solution at a constant temperature of 50°C for 10 min, and then immersed in an AZ300 solution for 3 min; the steps 31)-34) were repeated twice;

[0080] 4) Preparation of precursor solution

[0081] Lead acetate was configured into a 0.60 mol / L solution A, sodium hydroxide was configured into a 3.0 mol / L solution B, thiourea was configured into a 0.5 mol / L solution C, and sodium citrate was configured into a 0.5 mol / L solution D; then, the solutions A-D were mixed and configured into a precursor solution in the order of ABCD;

[0082] 5) depositing a lead sulfide film

[0083] The patterned substrate with surface pretreatment of step 3) is put into the precursor solution in step 4), the water bath temperature is kept at 50℃, the deposition time is 1h, and the angle with the liquid surface is 70°, thereby obtaining a patterned substrate with surface selective growth of a lead sulfide film.

[0084] Comparative Example 1

[0085] The present comparative example provides a method for preparing a patterned substrate with surface growth of a lead sulfide film, which is basically the same as that of Example 2, except that step 3) is omitted, i.e., the patterned substrate is not surface pretreated, and specifically:

[0086] 1) pretreating a Si / SiO2 substrate

[0087] The Si / SiO2 substrate is ultrasonically cleaned with deionized water, acetone and alcohol for 10 min respectively, and then dried with nitrogen for standby;

[0088] 2) preparation of a patterned substrate

[0089] A 10nm chromium and 100nm gold layer is deposited on the surface of the Si / SiO2 substrate pretreated in step 1) by magnetron sputtering, and then a metal layer is left in the local area of the substrate by using a photoetching stripping process;

[0090] 3) preparation of a precursor solution

[0091] Lead acetate is prepared into a 0.40mol / L solution A, sodium hydroxide is prepared into a 1.14mol / L solution B, thiourea is prepared into a 0.3mol / L solution C, and sodium citrate is prepared into a 0.3mol / L solution D; then, the solutions A-D are mixed and prepared into a precursor solution in the order of ABCD;

[0092] 4) depositing a lead sulfide film

[0093] The patterned substrate prepared in step 2) is put into the precursor solution in step 3), the water bath temperature is kept at 40℃, the deposition time is 2h, and the angle with the liquid surface is 70°, thereby obtaining a patterned substrate with surface selective growth of a lead sulfide film.

[0094] Performance test:

[0095] The present application takes Example 2 as an example to test the performance of the prepared patterned substrate with surface selective growth of a lead sulfide film, and the results are as follows:

[0096] 1) appearance and morphology

[0097] The appearance of the patterned substrate prepared in Example 2 and Comparative Example 1 was tested, and the results are shown in Figures 1-4 , Figure 1 is a surface morphology diagram (microscope measurement) of the lead sulfide thin film material deposited on the patterned substrate by chemical water bath in Comparative Example 1, wherein the square area is the area where the gold substrate is located, and the rest is the SiO2 substrate; Figure 2 is a surface morphology diagram (SEM measurement) of the lead sulfide thin film material deposited on the patterned substrate by chemical water bath in Comparative Example 1, wherein Figure 2 (a) is the surface morphology of the lead sulfide thin film grown on the metal, Figure 2 (b) is the surface morphology of the lead sulfide thin film grown on the SiO2; Figure 4 is a surface morphology diagram (microscope measurement) of the lead sulfide thin film material deposited on the patterned substrate obtained in Example 2 by chemical water bath, wherein the square area is the area where the gold substrate is located, and the rest is the SiO2 substrate; Figure 5 is a surface morphology diagram (SEM measurement) of the lead sulfide thin film material deposited on the patterned substrate obtained in Example 2 by chemical water bath, wherein Figure 5 (a) is the surface morphology of the lead sulfide thin film grown on the metal, Figure 5 (b) is the surface morphology of the lead sulfide thin film grown on the SiO2.

[0098] Comparative Example 1 Figure 1 and Figure 4 , Figure 4 in which no silver-gray lead sulfide thin film as shown in Figure 1 was found on the surface of the metal substrate. Comparative Example 1 Figure 2 and Figure 5 , Figure 5 in which no shaped lead sulfide grains were found on the surface of the metal substrate, indicating that there was no lead sulfide material attached, which is in sharp contrast to Figure 2 in which the surface of the metal substrate is uniformly and densely covered with lead sulfide grains. By special treatment of the surface of the patterned substrate, the surface properties of the patterned substrate are changed, the nucleation probability and growth rate of lead sulfide on different material surfaces are greatly different, and thus selective growth of lead sulfide thin film on the surface of the patterned substrate is realized.

[0099] In summary, the present application uses a specific solution treatment and a photolithography process to simply treat the surface of the patterned substrate, so as to selectively grow lead sulfide thin film on SiO2 and metal without changing the ratio of the deposition solution or the deposition environment and conditions. The method provided by the present application enables the lead sulfide thin film to precisely cover the photosensitive area and avoid the electrode area, avoiding the very complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process, and providing a reference value for improving the yield and performance of low-cost lead sulfide detectors.

[0100] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A method for preparing a patterned substrate with a selective growth of a lead sulfide thin film on the surface of the substrate, characterized in that, The method comprises the following steps: 1) surface modification of the patterned substrate in an oxidant solution to obtain a surface-modified patterned substrate; 2) spin coating photoresist on the surface of the patterned substrate, unmasked exposure and photoresist removal, repeated for multiple times to obtain a surface-preprocessed patterned substrate; 3) placing the surface-preprocessed patterned substrate obtained in step 2) into a precursor solution for growing lead sulfide film to perform a chemical deposition reaction, thereby obtaining a patterned substrate with selectively grown lead sulfide film material on the surface, wherein the patterned substrate is prepared by the following method: depositing 5-15 nm chromium and 50-150 nm gold on the surface of a Si / SiO2 substrate by magnetron sputtering, and then leaving the metal layer in the local area of the Si / SiO2 substrate by using a photolithography lift-off process to obtain the patterned substrate; the oxidant is a mixture of hydrogen peroxide and concentrated sulfuric acid with a mass ratio of 7:3; and the spin-coated photoresist in step 2) is: spin coating two layers of photoresist on the surface of the patterned substrate, the first layer of photoresist being a lift-off resist, and the second layer of photoresist being an ultraviolet resist. The method further comprises preprocessing the Si / SiO2 substrate in the preparation process of the patterned substrate, specifically: ultrasonically cleaning the Si / SiO2 substrate with deionized water, acetone and alcohol for 5-15 min, respectively, and then blowing dry with nitrogen for standby use.

2. The method for preparing a selectively grown lead sulfide thin film on a patterned substrate according to claim 1, characterized in that, The coating conditions of the first layer of photoresist are: spin coating at a speed of 500-4000 rpm, and then placing on a hot plate at 170℃ for drying for 10 min; the coating conditions of the second layer of photoresist are: spin coating at a speed of 500-5000 rpm, and then placing on a hot plate at 100℃ for drying for 10 min.

3. The method for preparing a selectively grown lead sulfide thin film on a patterned substrate according to claim 1, characterized in that, The unmasked exposure conditions in step 2) are: exposure time of 8-20 s; and the photoresist removal is specifically: soaking the exposed patterned substrate in an acetone solution for 10 min, and then soaking in an AZ300 solution for 1-3 min.

4. The method for preparing a selectively grown lead sulfide thin film on a patterned substrate according to claim 2, characterized in that, The temperature of the acetone solution is 40-60℃.

5. The method for preparing a selectively grown lead sulfide thin film on a patterned substrate according to claim 2, characterized in that, The precursor solution for growing lead sulfide film is prepared by the following configuration method:

6. The method of claim 5, wherein the patterned substrate is a glass substrate. configuring lead acetate into a solution A with a concentration of 0.01-1 mol / L; configuring sodium hydroxide into a solution B with a concentration of 0.1-10 mol / L; configuring thiourea into a solution C with a concentration of 0.01-1 mol / L; and configuring sodium citrate into a solution D with a concentration of 0.01-1 mol / L; mixing and configuring the solution A, the solution B, the solution C and the solution D in the order of ABCD to obtain the precursor solution for growing lead sulfide film. The chemical deposition conditions in step 4) are: deposition temperature of 40-60℃, deposition time of 0.5-2 h, and an included angle of 65-75° with the liquid surface.

7. The method of claim 6, wherein the patterned substrate is a glass substrate. ​

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