Preparation method of inorganic / organic thin film heterojunction photoelectric detector

Abstract

The invention belongs to the field of new photoelectric materials, and particularly discloses a preparation method of an inorganic / organic thin film heterojunction photoelectric detector. Comprising the following steps: 1) material selection and preparation: selecting a two-dimensional inorganic material with high mobility and broadband photoresponse characteristics and a low-cost, flexible and tunable organic material; 2) preparing an inorganic film: preparing the inorganic film by adopting a molecular beam epitaxy (MBE) method or a thermal evaporation deposition (TED) method, and accurately controlling the thickness and the quality of the film; 3) constructing a heterostructure: uniformly covering the organic solution on the surface of the inorganic film by using a spraying method or a spin-coating method, and performing heat treatment curing to form an inorganic / organic film heterojunction; 4) preparing an electrode: preparing an electrode structure on the heterojunction through a photoetching or electron beam evaporation technical means; the detector provided by the invention has excellent photoelectric properties from ultraviolet to infrared bands, and can be applied to the fields of biological monitoring, machine vision, intelligent image chips and the like.

Description

Technical Field

[0001] The invention belongs to the field of new optoelectronic materials, and specifically discloses a method for preparing an inorganic / organic thin film heterojunction photoelectric detector. Background Art

[0002] Heterojunction photoelectric sensor is a sensor based on photoelectric conversion technology, which uses the difference in electrical and optical properties between different semiconductor materials to produce photoelectric effect. Principle: When light is irradiated to the heterojunction interface, photons are absorbed and excite electrons in the semiconductor to jump from the valence band to the conduction band, forming electron-hole pairs. Due to the different energy band structures of different materials, electrons and holes are separated and transported at the heterojunction interface, thereby generating photogenerated electromotive force or photocurrent. This photoelectric conversion process enables heterojunction photoelectric sensors to sensitively detect and respond to light signals. Heterojunction photodetectors have shown many advantages in the current scientific and technological development, such as high sensitivity, fast response, and wide spectral response. However, it also has some disadvantages that cannot be ignored, which limit its application and development in certain fields. The following is a summary of the main shortcomings of heterojunction photodetectors at present: 1. Short carrier lifetime: In heterojunction photodetectors composed of some two-dimensional materials, the lifetime of photogenerated carriers may be short due to the characteristics of the materials or interface effects. This will affect the signal stability and response time of the detector. 2. Lattice mismatch problem: When constructing a heterojunction, there may be differences in the lattice constants between different semiconductor materials, resulting in lattice mismatch. Lattice mismatch not only increases the defect density of the interface, but also may affect the transport performance of carriers, thereby reducing the efficiency of the detector. 3. Low light absorption coefficient: The light absorption capacity of some two-dimensional materials is relatively weak, especially in the long wavelength range. This will result in the detector's low utilization of incident light, which in turn affects its sensitivity and detection range. Summary of the invention

[0003] In view of the above problems, the present invention discloses a method for preparing an inorganic / organic thin film heterojunction photodetector.

[0004] The purpose of the present invention is achieved through the following technical solutions.

[0005] A method for preparing an inorganic / organic thin film heterojunction photodetector comprises the following steps:

[0006] 1) Material selection and preparation: Select two-dimensional inorganic materials with high mobility and broadband photoresponse characteristics and low-cost, flexible and tunable organic materials;

[0007] 2) Preparation of inorganic thin films: Molecular beam epitaxy (MBE) or thermal evaporation deposition (TED) is used to prepare inorganic thin films, and the thickness and quality of the films are precisely controlled;

[0008] 3) Heterostructure construction: The organic solution is evenly coated on the surface of the inorganic film by spraying or spin coating, and then cured by heat treatment to form an inorganic / organic film heterojunction;

[0009] 4) Preparation of electrodes: The electrode structure is prepared on the heterojunction by means of photolithography or electron beam evaporation, which is an inorganic / organic thin film heterojunction photodetector.

[0010] Furthermore, in the above-mentioned method for preparing an inorganic / organic thin film heterojunction photoelectric detector, the two-dimensional inorganic material in step 1) is Cd3As2

[0011] Furthermore, in the above-mentioned method for preparing an inorganic / organic thin film heterojunction photodetector, the organic material in step 1) is a phthalocyanine organic compound.

[0012] Furthermore, in the above-mentioned method for preparing an inorganic / organic thin film heterojunction photoelectric detector, the phthalocyanine organic compound is 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II).

[0013] Furthermore, in the above-mentioned method for preparing an inorganic / organic thin film heterojunction photoelectric detector, the step 2) comprises the following steps:

[0014] 21) Select GaAs as the substrate material, thoroughly clean and treat the substrate to remove surface impurities and contaminants, ensure surface cleanliness and flatness, and then preheat to 300-600°C;

[0015] 22) placing high-purity Cd and As source materials in their respective beam source furnaces and heating them to 800-1200°C to evaporate them into gaseous molecules or atoms;

[0016] 23) The Cd and As molecular beams collimated by the pinhole are sprayed onto the preheated substrate surface;

[0017] 24) Generate Cd3As2 thin films using layered growth;

[0018] 25) Use reflection high energy electron diffraction (RHEED) and Auger analyzer to monitor the growth process and crystal quality of thin films in real time;

[0019] 26) After the growth is completed, the sample is slowly cooled from the high temperature environment to room temperature to avoid cracks or deformation caused by thermal stress.

[0020] Furthermore, in the above-mentioned method for preparing an inorganic / organic thin film heterojunction photoelectric detector, the step 3) comprises the following steps:

[0021] 31) putting 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) into an organic solvent and stirring evenly with a magnetic force, wherein the organic solvent is DMSO, and 1 g of 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) is put into 15-20 mL of DMSO;

[0022] 32) Thoroughly clean the surface of the inorganic film using chemical or physical methods to remove oil, dust and other contaminants;

[0023] 33) Preheating the inorganic film to 80-150°C;

[0024] 34) using a spray gun to evenly spray the solution prepared in step 31) onto the surface of the inorganic film;

[0025] 35) The inorganic film sprayed with the organic solution is placed in a heating furnace for heat treatment and solidification at a temperature of 100-120° C. for 2-4 hours to form an inorganic / organic film heterojunction.

[0026] Furthermore, in the above-mentioned method for preparing an inorganic / organic thin film heterojunction photoelectric detector, the step 4) comprises the following steps:

[0027] 41) Prepare the electron beam evaporation system and the target metal silver, and design and make the corresponding mask according to the required electrode size and structure;

[0028] 42) Cleaning and drying the heterojunction surface;

[0029] 43) evacuating the electron beam evaporation system and preheating the heterojunction surface to 300-500° C.;

[0030] 44) Start the electron gun to generate a focused electron beam to bombard the target material. During this process, the kinetic energy of the electron beam is converted into heat energy, causing the target material to evaporate and deposit on the heterojunction to form a thin film. A mask is used to control the shape and size of the electrode. When the electron beam passes through the mask, only a specific area of ​​the substrate will be covered by the deposited material.

[0031] 45) Using a film thickness monitor to monitor the growth of the film in real time to achieve the desired thickness and uniformity;

[0032] 46) After the evaporation is completed, the sample is allowed to cool naturally to room temperature in a vacuum to avoid cracks or deformation caused by thermal stress.

[0033] The present invention also discloses an inorganic / organic thin film heterojunction photoelectric detector, which is prepared by any of the methods described above.

[0034] The invention also discloses an inorganic / organic thin film heterojunction photoelectric detector, wherein the thickness of the inorganic thin film is 20-50 μm, and the thickness of the organic thin film is 10-20 μm.

[0035] The present invention also discloses the use of the inorganic / organic thin film heterojunction photoelectric detector in the preparation of biological monitoring, machine vision or intelligent image chips.

[0036] Compared with the existing technology, the present invention has the following advantages and beneficial effects:

[0037] The present invention discloses a method for preparing an inorganic / organic thin film heterojunction photodetector. The method realizes the construction of a high-performance photodetector through carefully designed steps and has the following obvious advantages: 1. Combination of material advantages: The two-dimensional inorganic material Cd3As2 with high mobility and broadband light response characteristics is selected and combined with low-cost, flexible and tunable phthalocyanine organic matter, which gives full play to the complementary advantages of the two in photoelectric performance and improves the comprehensive performance of the detector. 2. Precision preparation technology: The inorganic film is prepared by molecular beam epitaxy or thermal evaporation deposition, which ensures the high controllability of the thickness and quality of the film; at the same time, the organic solution is evenly covered on the inorganic film by spraying or spin coating, and cured by heat treatment to form a stable heterostructure, which improves the stability and reliability of the device. 3. Efficient electrode preparation: The electrode structure is accurately prepared on the heterojunction by photolithography or electron beam evaporation technology, which not only simplifies the process flow, but also improves the accuracy and consistency of the electrode, which is conducive to improving the photoelectric conversion efficiency and signal transmission quality of the detector. 4. Broad application prospects: The prepared inorganic / organic thin film heterojunction photodetector has excellent performance and can be widely used in biological monitoring, machine vision, intelligent image chips and other fields, providing strong technical support for the development of these fields. DETAILED DESCRIPTION

[0038] A method for preparing an inorganic / organic thin film heterojunction photodetector comprises the following steps:

[0039] 1) Material selection and preparation: Select two-dimensional inorganic materials with high mobility and broadband photoresponse characteristics and low-cost, flexible and tunable organic materials;

[0040] 2) Preparation of inorganic thin films: Molecular beam epitaxy (MBE) or thermal evaporation deposition (TED) is used to prepare inorganic thin films, and the thickness and quality of the films are precisely controlled;

[0041] 3) Heterostructure construction: The organic solution is evenly coated on the surface of the inorganic film by spraying or spin coating, and then cured by heat treatment to form an inorganic / organic film heterojunction;

[0042] 4) Preparation of electrodes: The electrode structure is prepared on the heterojunction by means of photolithography or electron beam evaporation, which is an inorganic / organic thin film heterojunction photodetector.

[0043] The two-dimensional inorganic material in step 1) is Cd3As2;

[0044] The organic material in step 1) is a phthalocyanine organic compound;

[0045] The phthalocyanine organic compound is 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II);

[0046] The step 2) comprises the following steps:

[0047] 21) Select GaAs as the substrate material, thoroughly clean and treat the substrate to remove surface impurities and contaminants, ensure surface cleanliness and flatness, and then preheat to 300-600°C;

[0048] 22) placing high-purity Cd and As source materials in their respective beam source furnaces and heating them to 800-1200°C to evaporate them into gaseous molecules or atoms;

[0049] 23) The Cd and As molecular beams collimated by the pinhole are sprayed onto the preheated substrate surface;

[0050] 24) Generate Cd3As2 thin films using layered growth;

[0051] 25) Use reflection high energy electron diffraction (RHEED) and Auger analyzer to monitor the growth process and crystal quality of thin films in real time;

[0052] 26) After the growth is completed, the sample is slowly cooled from the high temperature environment to room temperature to avoid cracks or deformation caused by thermal stress.

[0053] The step 3) comprises the following steps:

[0054] 31) putting 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) into an organic solvent and stirring evenly with a magnetic force, wherein the organic solvent is DMSO, and 1 g of 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) is put into 15-20 mL of DMSO;

[0055] 32) Thoroughly clean the surface of the inorganic film using chemical or physical methods to remove oil, dust and other contaminants;

[0056] 33) Preheating the inorganic film to 80-150°C;

[0057] 34) using a spray gun to evenly spray the solution prepared in step 31) onto the surface of the inorganic film;

[0058] 35) The inorganic film sprayed with the organic solution is placed in a heating furnace for heat treatment and solidification at a temperature of 100-120° C. for 2-4 hours to form an inorganic / organic film heterojunction.

[0059] The step 4) comprises the following steps:

[0060] 41) Prepare the electron beam evaporation system and the target metal silver, and design and make the corresponding mask according to the required electrode size and structure;

[0061] 42) Cleaning and drying the heterojunction surface;

[0062] 43) evacuating the electron beam evaporation system and preheating the heterojunction surface to 300-500° C.;

[0063] 44) Start the electron gun to generate a focused electron beam to bombard the target material. During this process, the kinetic energy of the electron beam is converted into heat energy, causing the target material to evaporate and deposit on the heterojunction to form a thin film. A mask is used to control the shape and size of the electrode. When the electron beam passes through the mask, only a specific area of ​​the substrate will be covered by the deposited material.

[0064] 45) Using a film thickness monitor to monitor the growth of the film in real time to achieve the desired thickness and uniformity;

[0065] 46) After the evaporation is completed, the sample is allowed to cool naturally to room temperature in a vacuum to avoid cracks or deformation caused by thermal stress.

[0066] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below through embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0067] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0068] Example 1

[0069] A method for preparing an inorganic / organic thin film heterojunction photodetector comprises the following steps:

[0070] 1) Material selection and preparation: Select two-dimensional inorganic materials with high mobility and broadband photoresponse characteristics and low-cost, flexible and tunable organic materials;

[0071] 2) Preparation of inorganic thin films: Molecular beam epitaxy (MBE) or thermal evaporation deposition (TED) is used to prepare inorganic thin films, and the thickness and quality of the films are precisely controlled;

[0072] 3) Heterostructure construction: The organic solution is evenly coated on the surface of the inorganic film by spraying or spin coating, and then cured by heat treatment to form an inorganic / organic film heterojunction;

[0073] 4) Preparation of electrodes: The electrode structure is prepared on the heterojunction by means of photolithography or electron beam evaporation, which is an inorganic / organic thin film heterojunction photodetector.

[0074] The two-dimensional inorganic material in step 1) is Cd3As2;

[0075] The organic material in step 1) is a phthalocyanine organic compound;

[0076] The phthalocyanine organic compound is 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II);

[0077] The step 2) comprises the following steps:

[0078] 21) Select GaAs as the substrate material, clean and treat the substrate thoroughly to remove impurities and contaminants on the surface, ensure surface cleanliness and flatness, and then preheat to 300°C;

[0079] 22) High-purity Cd and As source materials are placed in their respective beam source furnaces and heated to 800°C to evaporate them into gaseous molecules or atoms;

[0080] 23) The Cd and As molecular beams collimated by the pinhole are sprayed onto the preheated substrate surface;

[0081] 24) Generate Cd3As2 thin films using layered growth;

[0082] 25) Use reflection high energy electron diffraction (RHEED) and Auger analyzer to monitor the growth process and crystal quality of thin films in real time;

[0083] 26) After the growth is completed, the sample is slowly cooled from the high temperature environment to room temperature to avoid cracks or deformation caused by thermal stress.

[0084] The step 3) comprises the following steps:

[0085] 31) putting 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) into an organic solvent and stirring evenly with a magnetic force, wherein the organic solvent is DMSO, and 1 g of 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) is put into 15 mL of DMSO;

[0086] 32) Thoroughly clean the surface of the inorganic film using chemical or physical methods to remove oil, dust and other contaminants;

[0087] 33) Preheating the inorganic film to 80° C.

[0088] 34) using a spray gun to evenly spray the solution prepared in step 31) onto the surface of the inorganic film;

[0089] 35) The inorganic film sprayed with the organic solution is placed in a heating furnace for heat treatment and solidification at a temperature of 120° C. for 2 hours to form an inorganic / organic film heterojunction.

[0090] The step 4) comprises the following steps:

[0091] 41) Prepare the electron beam evaporation system and the target metal silver, and design and make the corresponding mask according to the required electrode size and structure;

[0092] 42) Cleaning and drying the heterojunction surface;

[0093] 43) evacuating the electron beam evaporation system and preheating the heterojunction surface to 300° C.;

[0094] 44) Start the electron gun to generate a focused electron beam to bombard the target material. During this process, the kinetic energy of the electron beam is converted into heat energy, causing the target material to evaporate and deposit on the heterojunction to form a thin film. A mask is used to control the shape and size of the electrode. When the electron beam passes through the mask, only a specific area of ​​the substrate will be covered by the deposited material.

[0095] 45) Using a film thickness monitor to monitor the growth of the film in real time to achieve the desired thickness and uniformity;

[0096] 46) After the evaporation is completed, the sample is allowed to cool naturally to room temperature in a vacuum to avoid cracks or deformation caused by thermal stress.

[0097] Performance Testing:

[0098] After the preparation, the device was tested for light and dark current-voltage characteristics. In the dark state, the dark current of the device was 1.03nA under 0V bias; at a wavelength of 325nm and a light intensity of 420mW / cm 2Under ultraviolet light irradiation, the photocurrent of the device is 1.71μA at 0V bias, and the light-to-dark current ratio of the device is 1660.

[0099] Example 2

[0100] A method for preparing an inorganic / organic thin film heterojunction photodetector comprises the following steps:

[0101] 1) Material selection and preparation: Select two-dimensional inorganic materials with high mobility and broadband photoresponse characteristics and low-cost, flexible and tunable organic materials;

[0102] 2) Preparation of inorganic thin films: Molecular beam epitaxy (MBE) or thermal evaporation deposition (TED) is used to prepare inorganic thin films, and the thickness and quality of the films are precisely controlled;

[0103] 3) Heterostructure construction: The organic solution is evenly coated on the surface of the inorganic film by spraying or spin coating, and then cured by heat treatment to form an inorganic / organic film heterojunction;

[0104] 4) Preparation of electrodes: The electrode structure is prepared on the heterojunction by means of photolithography or electron beam evaporation, which is an inorganic / organic thin film heterojunction photodetector.

[0105] The two-dimensional inorganic material in step 1) is Cd3As2;

[0106] The organic material in step 1) is a phthalocyanine organic compound;

[0107] The phthalocyanine organic compound is 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II);

[0108] The step 2) comprises the following steps:

[0109] 21) Select GaAs as the substrate material, thoroughly clean and treat the substrate to remove surface impurities and contaminants, ensure surface cleanliness and flatness, and then preheat to 450°C;

[0110] 22) High-purity Cd and As source materials are placed in their respective beam source furnaces and heated to 1000°C to evaporate them into gaseous molecules or atoms;

[0111] 23) The Cd and As molecular beams collimated by the pinhole are sprayed onto the preheated substrate surface;

[0112] 24) Generate Cd3As2 thin films using layered growth;

[0113] 25) Use reflection high energy electron diffraction (RHEED) and Auger analyzer to monitor the growth process and crystal quality of thin films in real time;

[0114] 26) After the growth is completed, the sample is slowly cooled from the high temperature environment to room temperature to avoid cracks or deformation caused by thermal stress.

[0115] The step 3) comprises the following steps:

[0116] 31) putting 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) into an organic solvent and stirring evenly with a magnetic force, wherein the organic solvent is DMSO, and 1 g of 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) is put into 17.5 mL of DMSO;

[0117] 32) Thoroughly clean the surface of the inorganic film using chemical or physical methods to remove oil, dust and other contaminants;

[0118] 33) Preheating the inorganic film to 110° C.;

[0119] 34) using a spray gun to evenly spray the solution prepared in step 31) onto the surface of the inorganic film;

[0120] 35) The inorganic film sprayed with the organic solution is placed in a heating furnace for heat treatment and solidification at a temperature of 110° C. for 3 hours to form an inorganic / organic film heterojunction.

[0121] The step 4) comprises the following steps:

[0122] 41) Prepare the electron beam evaporation system and the target metal silver, and design and make the corresponding mask according to the required electrode size and structure;

[0123] 42) Cleaning and drying the heterojunction surface;

[0124] 43) evacuating the electron beam evaporation system and preheating the heterojunction surface to 400° C.;

[0125] 44) Start the electron gun to generate a focused electron beam to bombard the target material. During this process, the kinetic energy of the electron beam is converted into heat energy, causing the target material to evaporate and deposit on the heterojunction to form a thin film. A mask is used to control the shape and size of the electrode. When the electron beam passes through the mask, only a specific area of ​​the substrate will be covered by the deposited material.

[0126] 45) Using a film thickness monitor to monitor the growth of the film in real time to achieve the desired thickness and uniformity;

[0127] 46) After the evaporation is completed, the sample is allowed to cool naturally to room temperature in a vacuum to avoid cracks or deformation caused by thermal stress.

[0128] After the preparation, the device was tested for light and dark current-voltage characteristics. In the dark state, the dark current of the device was 1.10nA under 0V bias; at a wavelength of 325nm and a light intensity of 420mW / cm 2 Under ultraviolet light irradiation, the photocurrent of the device is 1.65μA at 0V bias, and the light-to-dark current ratio of the device is 1500.

[0129] Example 3

[0130] A method for preparing an inorganic / organic thin film heterojunction photodetector comprises the following steps:

[0131] 1) Material selection and preparation: Select two-dimensional inorganic materials with high mobility and broadband photoresponse characteristics and low-cost, flexible and tunable organic materials;

[0132] 2) Preparation of inorganic thin films: Molecular beam epitaxy (MBE) or thermal evaporation deposition (TED) is used to prepare inorganic thin films, and the thickness and quality of the films are precisely controlled;

[0133] 3) Heterostructure construction: The organic solution is evenly coated on the surface of the inorganic film by spraying or spin coating, and then cured by heat treatment to form an inorganic / organic film heterojunction;

[0134] 4) Preparation of electrodes: The electrode structure is prepared on the heterojunction by means of photolithography or electron beam evaporation, which is an inorganic / organic thin film heterojunction photodetector.

[0135] The two-dimensional inorganic material in step 1) is Cd3As2;

[0136] The organic material in step 1) is a phthalocyanine organic compound;

[0137] The phthalocyanine organic compound is 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II);

[0138] The step 2) comprises the following steps:

[0139] 21) Select GaAs as the substrate material, clean and treat the substrate thoroughly to remove surface impurities and contaminants, ensure surface cleanliness and flatness, and then preheat to 600°C;

[0140] 22) High-purity Cd and As source materials are placed in their respective beam source furnaces and heated to 1200°C to evaporate them into gaseous molecules or atoms;

[0141] 23) The Cd and As molecular beams collimated by the pinhole are sprayed onto the preheated substrate surface;

[0142] 24) Generate Cd3As2 thin films using layered growth;

[0143] 25) Use reflection high energy electron diffraction (RHEED) and Auger analyzer to monitor the growth process and crystal quality of thin films in real time;

[0144] 26) After the growth is completed, the sample is slowly cooled from the high temperature environment to room temperature to avoid cracks or deformation caused by thermal stress.

[0145] The step 3) comprises the following steps:

[0146] 31) putting 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) into an organic solvent and stirring evenly with a magnetic force, wherein the organic solvent is DMSO, and 1 g of 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) is put into 20 mL of DMSO;

[0147] 32) Thoroughly clean the surface of the inorganic film using chemical or physical methods to remove oil, dust and other contaminants;

[0148] 33) Preheating the inorganic film to 150° C.

[0149] 34) using a spray gun to evenly spray the solution prepared in step 31) onto the surface of the inorganic film;

[0150] 35) The inorganic film sprayed with the organic solution is placed in a heating furnace for heat treatment and solidification at a temperature of 120° C. for 2 hours to form an inorganic / organic film heterojunction.

[0151] The step 4) comprises the following steps:

[0152] 41) Prepare the electron beam evaporation system and the target metal silver, and design and make the corresponding mask according to the required electrode size and structure;

[0153] 42) Cleaning and drying the heterojunction surface;

[0154] 43) evacuating the electron beam evaporation system and preheating the heterojunction surface to 500° C.;

[0155] 44) Start the electron gun to generate a focused electron beam to bombard the target material. During this process, the kinetic energy of the electron beam is converted into heat energy, causing the target material to evaporate and deposit on the heterojunction to form a thin film. A mask is used to control the shape and size of the electrode. When the electron beam passes through the mask, only a specific area of ​​the substrate will be covered by the deposited material.

[0156] 45) Using a film thickness monitor to monitor the growth of the film in real time to achieve the desired thickness and uniformity;

[0157] 46) After the evaporation is completed, the sample is allowed to cool naturally to room temperature in a vacuum to avoid cracks or deformation caused by thermal stress.

[0158] After the preparation, the device was tested for light and dark current-voltage characteristics. In the dark state, the dark current of the device was 1.08nA under 0V bias; at a wavelength of 325nm and a light intensity of 420mW / cm 2 Under ultraviolet light irradiation, the photocurrent of the device is 1.75μA at 0V bias, and the light-to-dark current ratio of the device is 1620.

[0159] It can be seen from the above embodiments that the method for preparing the inorganic / organic thin film heterojunction photodetector of the present invention has significant advantages. First, by selecting the two-dimensional Cd3As2 inorganic material with high mobility and broadband light response and the low-cost, flexible and tunable phthalocyanine organic matter as the material basis, the dual optimization of performance and cost is achieved. Secondly, the inorganic film is prepared by molecular beam epitaxy or thermal evaporation deposition, which ensures that the thickness and quality of the film are accurately controllable, laying a solid foundation for the construction of high-performance photodetectors. In the process of heterostructure construction, the organic solution is evenly covered on the surface of the inorganic film by spraying or spin coating, and cured by heat treatment to form a stable inorganic / organic thin film heterojunction. This method not only simplifies the preparation process, but also improves the interface quality of the heterojunction, which is conducive to improving the photoelectric conversion efficiency of the device. In addition, the present invention also uses photolithography or electron beam evaporation technology to prepare the electrode structure, which further improves the performance and reliability of the device. The photodetector finally prepared shows excellent photocurrent response characteristics under ultraviolet light irradiation, and the light-to-dark current ratio is as high as 1660, showing good application prospects. In summary, the method of the present invention has the advantages of reasonable material selection, simple preparation process, low cost, superior performance, etc., and is expected to promote the further development of the field of photoelectric detectors.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Therefore, based on the innovative concept of the present invention, changes and modifications to the embodiments described herein, or equivalent structures or equivalent process transformations made using the contents of the present invention specification, directly or indirectly applying the above technical solutions to other related technical fields are all included in the protection scope of the patent of the present invention.

Claims

1. A method for preparing an inorganic / organic thin film heterojunction photodetector, characterized in that: The following steps are involved: 1) Material selection and preparation: Select two-dimensional inorganic materials with high mobility and broadband photoresponse characteristics and low-cost, flexible and tunable organic materials; 2) Preparation of inorganic thin films: Molecular beam epitaxy (MBE) or thermal evaporation deposition (TED) is used to prepare inorganic thin films, and the thickness and quality of the films are precisely controlled; 3) Heterostructure construction: The organic solution is evenly coated on the surface of the inorganic film by spraying or spin coating, and then cured by heat treatment to form an inorganic / organic film heterojunction; 4) Preparation of electrodes: The electrode structure is prepared on the heterojunction by means of photolithography or electron beam evaporation, which is an inorganic / organic thin film heterojunction photodetector.

2. The method for preparing an inorganic / organic thin film heterojunction photodetector according to claim 1, characterized in that: The two-dimensional inorganic material in step 1) is Cd3As2.

3. The method for preparing an inorganic / organic thin film heterojunction photodetector according to claim 1, characterized in that: The organic material in step 1) is a phthalocyanine organic compound.

4. The method for preparing an inorganic / organic thin film heterojunction photodetector according to claim 3, characterized in that: The phthalocyanine organic compound is 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II).

5. The method for preparing an inorganic / organic thin film heterojunction photodetector according to claim 1, characterized in that: The step 2) comprises the following steps: 21) Select GaAs as the substrate material, thoroughly clean and treat the substrate to remove surface impurities and contaminants, ensure surface cleanliness and flatness, and then preheat to 300-600°C; 22) placing high-purity Cd and As source materials in their respective beam source furnaces and heating them to 800-1200°C to evaporate them into gaseous molecules or atoms; 23) The Cd and As molecular beams collimated by the pinhole are sprayed onto the preheated substrate surface; 24) Generate Cd3As2 thin films using layered growth; 25) Use reflection high energy electron diffraction (RHEED) and Auger analyzer to monitor the growth process and crystal quality of thin films in real time; 26) After the growth is completed, the sample is slowly cooled from the high temperature environment to room temperature to avoid cracks or deformation caused by thermal stress.

6. The method for preparing an inorganic / organic thin film heterojunction photodetector according to claim 1, characterized in that: The step 3) comprises the following steps: 31) putting 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) into an organic solvent and stirring evenly with a magnetic force, wherein the organic solvent is DMSO, and 1 g of 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine zinc (II) is put into 15-20 mL of DMSO; 32) Thoroughly clean the surface of the inorganic film using chemical or physical methods to remove oil, dust and other contaminants; 33) Preheating the inorganic film to 80-150°C; 34) using a spray gun to evenly spray the solution prepared in step 31) onto the surface of the inorganic film; 35) The inorganic film sprayed with the organic solution is placed in a heating furnace for heat treatment and solidification at a temperature of 100-120° C. for 2-4 hours to form an inorganic / organic film heterojunction.

7. The method for preparing an inorganic / organic thin film heterojunction photodetector according to claim 1, characterized in that: The step 4) comprises the following steps: 41) Prepare the electron beam evaporation system and the target metal silver, and design and make the corresponding mask according to the required electrode size and structure; 42) Cleaning and drying the heterojunction surface; 43) evacuating the electron beam evaporation system and preheating the heterojunction surface to 300-500° C.; 44) Start the electron gun to generate a focused electron beam to bombard the target material. During this process, the kinetic energy of the electron beam is converted into heat energy, causing the target material to evaporate and deposit on the heterojunction to form a thin film. A mask is used to control the shape and size of the electrode. When the electron beam passes through the mask, only a specific area of ​​the substrate will be covered by the deposited material. 45) Using a film thickness monitor to monitor the growth of the film in real time to achieve the desired thickness and uniformity; 46) After the evaporation is completed, the sample is allowed to cool naturally to room temperature in a vacuum to avoid cracks or deformation caused by thermal stress.

8. An inorganic / organic thin film heterojunction photodetector, characterized in that: The method is prepared by any one of claims 1 to 7.

9. The inorganic / organic thin film heterojunction photodetector according to claim 9, characterized in that: The thickness of the inorganic film is 20-50 μm, and the thickness of the organic film is 10-20 μm.

10. Use of the inorganic / organic thin film heterojunction photodetector according to claim 9 in the preparation of biological monitoring, machine vision or intelligent image chips.