An organic-inorganic hybrid heterojunction solar blind photodetector and a preparation method thereof

Abstract

The application provides an organic-inorganic hybrid heterojunction solar-blind photodetector and a preparation method thereof. The photodetector comprises an Al2O3 substrate, a Ga2O3 light absorption layer, a 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] layer, a first electrode and a second electrode. The Ga2O3 light absorption layer is located on the Al2O3 substrate, the 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] layer is located on the side of the Ga2O3 light absorption layer away from the Al2O3 substrate, the first electrode is located on the side of the 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] layer away from the Ga2O3 light absorption layer, the second electrode is located on the side of the Ga2O3 light absorption layer away from the Al2O3 substrate, and the first electrode and the second electrode do not directly contact. The Ga2O3 light absorption layer and the 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] layer form a heterojunction, form a built-in electric field, and can separate photo-generated carriers. The photodetector has the characteristics of zero power consumption.

Description

Technical Field

[0001] This invention belongs to the field of photoelectric conversion technology, specifically relating to an organic-inorganic hybrid heterojunction solar-blind photodetector and its preparation method. Background Technology

[0002] Solar-blind detection systems, characterized by high sensitivity and accuracy, have been designed for applications in optical communication, flame detection, deep ultraviolet imaging, missile guidance, and environmental monitoring. As a crucial component of solar-blind detection systems, solar-blind photodetectors have received widespread attention. As the most widely used photodetector, silicon-based solar-blind photodetectors require expensive filters to block high-wavelength photons due to silicon's narrow bandgap (1.12 eV). In recent decades, many ultra-wide bandgap semiconductors, such as diamond, AlN, and Al... x Ga 1-x N and Mg x Zn 1-x All three types of Ga2O3 meet the standards for solar-blind photodetectors, with a cutoff wavelength below 280 nm. However, the lack of mature epitaxial growth and bandgap modulation techniques limits their practical application. Ga2O3, especially the most stable β-Ga2O3, is a naturally solar-blind material due to its ultra-wide bandgap (~4.8 eV). Currently, Ga2O3 heterojunction photodetectors are mainly based on all-inorganic materials. Inorganic material manufacturing technology is highly dependent on expensive high-vacuum and high-temperature manufacturing infrastructure, which will limit the large-scale production of self-powered photodetectors. Summary of the Invention

[0003] To address the aforementioned technical problems, the purpose of this invention is to propose an organic-inorganic hybrid heterojunction solar-blind photodetector and its preparation method, which reduces production costs and has self-powered capability, and can be applied to photoelectric detection.

[0004] To solve the above-mentioned technical problems, the present invention provides a technical solution as follows: an organic-inorganic hybrid heterojunction solar-blind photodetector, characterized in that it comprises an Al2O3 substrate, a Ga2O3 light-absorbing layer, a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer, and a first electrode and a second electrode; wherein the Ga2O3 light-absorbing layer is located on the Al2O3 substrate, and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is located on the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate layer. The area of ​​the cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is smaller than that of the Ga2O3 light-absorbing layer. The first electrode is located on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer away from the Ga2O3 light-absorbing layer, and the second electrode is located on the side of the Ga2O3 light-absorbing layer away from the Al2O3 substrate. The first and second electrodes are not in direct contact. The Ga2O3 light-absorbing layer and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer form a heterojunction, creating a built-in electric field that can separate photogenerated carriers.

[0005] The first electrode and the second electrode are both Ti / Au composite electrodes. The Ti / Au composite electrode includes a Ti metal layer and an Au metal layer. The thickness of the Ti layer is 5-15 nm and the thickness of the Au layer is 45-55 nm.

[0006] The thickness of the Ga2O3 light-absorbing layer is 400 nm, and the thickness of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is 200 nm.

[0007] The area of ​​the 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] layer is 2 / 3 of the area of ​​the Ga2O3 light-absorbing layer.

[0008] The present invention also includes a second technical solution, a method for preparing the above-mentioned organic-inorganic hybrid heterojunction solar-blind photodetector, comprising the following steps: using Al2O3 as a substrate, a Ga2O3 thin film is grown on the Al2O3 substrate by metal-organic chemical vapor deposition, using trimethylgallium and oxygen as reaction raw materials, the substrate temperature is 790℃, thereby forming a Ga2O3 light-absorbing layer.

[0009] A shielding layer is fabricated on the side of the Ga2O3 light-absorbing layer away from the Al2O3 substrate, and the shielding layer covers part of the Ga2O3 light-absorbing layer.

[0010] A 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution was spin-coated onto the side of the Ga2O3 light-absorbing layer away from the Al2O3 substrate to form a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer. The shielding layer was then removed to form a Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer, which constituted a heterojunction.

[0011] Using a photomask, electrodes are fabricated on the side of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] opposite to the Ga2O3 light-absorbing layer and on the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate, respectively, to form the first electrode and the second electrode.

[0012] The electrode fabrication process includes: sequentially sputtering a Ti metal layer with a thickness of 5-15 nm and an Au metal layer with a thickness of 45-55 nm using magnetron sputtering.

[0013] The magnetron sputtering process conditions include: a cavity pressure of 1×10⁻⁶ after vacuuming. 4 The substrate temperature was room temperature, the working atmosphere was Ar gas, the working pressure was 1.2 Pa, the sputtering power was 40 W, the sputtering time of the Ti metal layer was 2 minutes, and the sputtering time of the Au metal layer was 5 minutes.

[0014] The shielding layer is a heat-release tape. Removing the shielding layer involves heating on an 80°C heating table for 20 minutes to remove the heat-release tape.

[0015] The spin coating conditions are: 500 r / min for 5 seconds; or 3000 r / min for 40 seconds.

[0016] The preparation process of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution is as follows: 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] is dispersed in tetrahydrofuran solution and sonicated for 20 minutes. The mass-to-volume ratio of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] to tetrahydrofuran solution is 10 mg: 1 ml.

[0017] The shielding layer covers one-third of the Ga2O3 light-absorbing layer;

[0018] The Al2O3 substrate undergoes pretreatment, which includes immersing the substrate sequentially in acetone, ethanol, and deionized water, and then sonicating it for 10 minutes each. After removal, the substrate is rinsed with deionized water and finally dried with dry air to obtain the pretreated Al2O3 substrate.

[0019] The beneficial effects of this invention are as follows:

[0020] 1) The method of the present invention has a simple preparation process. It uses metal-organic chemical vapor deposition to grow Ga2O3 thin films, which has strong process controllability. The organic compound 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] prepared by spin coating is used to construct a heterojunction with Ga2O3. The resulting organic layer film has a dense surface, stable and uniform thickness, can be prepared on a large area, has good repeatability and strong stability, and the equipment used to prepare the organic compound has low cost.

[0021] 2) The organic-inorganic hybrid heterojunction solar-blind photodetector of the present invention, Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction, can operate at 0V bias voltage and has the characteristics of zero power consumption. Its self-powered and spectral selectivity have potential application prospects in the field of solar-blind detection.

[0022] 3) The organic-inorganic hybrid heterojunction solar-blind photodetector of the present invention has a synergistic effect in the organic-inorganic hybrid heterojunction, that is, the material has the advantages of both inorganic and organic components. It utilizes the superior electronic properties of inorganic materials as a way to improve device performance, while maintaining some properties of the organic part, such as flexibility and biocompatibility, so that the detector has a wider range of application prospects.

[0023] 4) The organic-inorganic hybrid heterojunction solar-blind photodetector of the present invention, 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline], has a simple manufacturing process, high conductivity, and high hole mobility. 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] has suitable energy levels. The HOMO energy level of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] is higher than the valence band of Ga2O3, ensuring efficient hole transport, while the LUMO energy level is higher than the conduction band of Ga2O3, blocking electron transport. 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] has an appropriate absorption range. 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] has a high hole mobility, ensuring rapid hole transport and separation. 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] has good thermal stability, hydrophobicity, and good solubility in common solutions. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the organic-inorganic hybrid heterojunction solar-blind photodetector according to an embodiment of the present invention;

[0025] Figure 2 The image shows the IV curves of the organic-inorganic hybrid heterojunction solar-blind photodetector of this invention under darkness and different light intensities at 254 nm.

[0026] Figure 3This invention relates to an organic-inorganic hybrid heterojunction solar-blind photodetector operating at 0 bias and 1000 μW / cm². 2 It curve at a light intensity of 254nm;

[0027] Figure 4 This is the spectral response curve of the organic-inorganic hybrid heterojunction solar-blind photodetector according to an embodiment of the present invention. Detailed Implementation

[0028] The present invention will now be illustrated by the following embodiments, but these are not intended to limit the scope of the invention. Unless otherwise specified, the means used in the embodiments are conventional means in the art.

[0029] Example 1:

[0030] A method for fabricating an organic-inorganic hybrid heterojunction solar-blind photodetector includes the following steps:

[0031] Using Al2O3 as a substrate, a Ga2O3 thin film is grown on the Al2O3 substrate by metal-organic chemical vapor deposition, using trimethylgallium and oxygen as reactants, and the substrate temperature is 790℃, thus forming a Ga2O3 light-absorbing layer.

[0032] A shielding layer is formed on the side of the Ga2O3 light-absorbing layer away from the Al2O3 substrate, and the shielding layer covers a portion of the Ga2O3 light-absorbing layer.

[0033] A 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution was spin-coated onto the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate to form a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer. The shielding layer was then removed to form a Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer, constituting a heterojunction.

[0034] Using a photomask, electrodes are fabricated on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] opposite to the Ga2O3 light-absorbing layer and on the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate, respectively, to form a first electrode and a second electrode.

[0035] To facilitate a clear understanding of the present invention, specific embodiments are as follows: A method for fabricating an organic-inorganic hybrid heterojunction solar-blind photodetector includes the following steps:

[0036] A 10mm × 10mm × 0.5mm Al2O3 substrate with its C-side surface was used as a substrate. The substrate was sequentially immersed in acetone, ethanol, and deionized water, each ultrasonically cleaned for 10 minutes. After removal, it was rinsed with deionized water and finally dried with dry air to obtain the treated Al2O3 substrate, ready for use. The treated Al2O3 substrate was placed in a deposition chamber, and a Ga2O3 thin film was grown on the Al2O3 substrate using organometallic chemical vapor deposition (GMCVD). Trimethylgallium and oxygen were used as reactants, and the substrate temperature was 790℃, forming a Ga2O3 light-absorbing layer with a thickness of 400nm.

[0037] 10 mg of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC) powder was dispersed in 1 ml of tetrahydrofuran solution and sonicated for 20 minutes to disperse the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC) powder, forming a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution (TAPC solution), which was set aside for later use. One-third of the prepared Ga2O3 film was covered with heat-release tape, and 100 μL of TAPC solution was pipetted onto the uncovered area. The film was rotated at 500 rpm for 5 seconds and then at 3000 rpm for 40 seconds to obtain a Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction. The obtained Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction was heated on an 80°C heating stage for 20 minutes, and the heat-release tape was removed. The resulting Ga2O3 / TAPC heterojunction was then masked with a perforated mask, and a 10 nm thick Ti metal layer and a 50 nm thick Au metal layer were successively sputtered using magnetron sputtering to obtain an electrode with a diameter of 3 mm. The sputtering process conditions were as follows: after vacuuming, the cavity pressure was 1 × 10⁻⁶. 4 Pa, substrate temperature is room temperature, working atmosphere is Ar gas, working pressure is 1.2 Pa, sputtering power is 40 W, sputtering time of Ti metal layer is 2 minutes, sputtering time of Au metal layer is 5 minutes, forming Ti / Au composite electrode, i.e., obtaining the first electrode and the second electrode, both of which are made of Ti / Au composite electrode.

[0038] The organic-inorganic hybrid heterojunction solar-blind photodetector prepared in this application embodiment has the following structure: Figure 1As shown, the electrode includes an Al2O3 substrate 1, a Ga2O3 light-absorbing layer 2, a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3, a first electrode 4, and a second electrode 5; wherein the Ga2O3 light-absorbing layer 2 is located on the Al2O3 substrate 1, the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is located on the side of the Ga2O3 light-absorbing layer 2 facing away from the Al2O3 substrate 1, and the area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is smaller than that of the Al2O3 substrate 1. The area of ​​the Ga2O3 light-absorbing layer 2 is such that the first electrode 4 is located on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 away from the Ga2O3 light-absorbing layer 2, and the second electrode 5 is located on the side of the Ga2O3 light-absorbing layer 2 away from the Al2O3 substrate 1. The first electrode 4 and the second electrode 5 are not in direct contact. The Ga2O3 light-absorbing layer 2 and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 form a heterojunction, which creates a built-in electric field that can separate photogenerated carriers.

[0039] In this design, both the first electrode 4 and the second electrode 5 are Ti / Au composite electrodes, comprising a Ti metal layer and an Au metal layer. The thickness of the Ti metal layer is 10 nm, and the thickness of the Au metal layer is 50 nm. Both the first electrode 4 and the second electrode 5 have a diameter of 30 nm. The Ga2O3 light-absorbing layer 2 has a thickness of 400 nm, and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 has a thickness of 200 nm. The area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is two-thirds the area of ​​the Ga2O3 light-absorbing layer 2.

[0040] like Figure 4 As shown, the organic-inorganic hybrid heterojunction solar-blind photodetector prepared in this embodiment exhibits a sharp increase in current and rectification characteristics under 254nm illumination, demonstrating excellent spectral selectivity. Figure 2 As shown, under dark conditions, it exhibits extremely low dark current. This heterojunction solar-blind photodetector can operate at 0 bias voltage and has the characteristic of zero power consumption. Figure 3 The Ga2O3 / TAPC organic-inorganic hybrid heterojunction solar-blind photodetector is presented at 0 bias and 1000 μW / cm. 2 The It curve at a wavelength of 254 nm under light intensity. Multiple cycles of testing were performed, and the device exhibited good repeatability. In darkness, the dark current of the detector is 10. -14 A, when 1000 μW / cm 2 After irradiation with 254nm light, the current rapidly increased to 10.-8 A, the contrast ratio is close to 10. 6 .

[0041] Example 2

[0042] A method for fabricating an organic-inorganic hybrid heterojunction solar-blind photodetector includes the following steps:

[0043] A 10mm × 10mm × 0.5mm Al2O3 substrate with its C-side surface was used as a substrate. The substrate was sequentially immersed in acetone, ethanol, and deionized water, each ultrasonically cleaned for 10 minutes. After removal, it was rinsed with deionized water and finally dried with dry air to obtain the treated Al2O3 substrate, ready for use. The treated Al2O3 substrate was placed in a deposition chamber, and a Ga2O3 thin film was grown on the Al2O3 substrate using organometallic chemical vapor deposition (GMCVD). Trimethylgallium and oxygen were used as reactants, and the substrate temperature was 790℃, forming a Ga2O3 light-absorbing layer with a thickness of 400nm.

[0044] 10 mg of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC) powder was dispersed in 1 ml of tetrahydrofuran solution and sonicated for 20 minutes to form a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution (TAPC solution), which was then set aside. One-third of the prepared Ga2O3 film was covered with heat-release tape, and 100 μL of TAPC solution was pipetted onto the uncovered area. The film was then rotated at 500 rpm for 5 seconds to obtain a Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction. The obtained Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction was heated on an 80°C heating stage for 20 minutes, and the heat-release tape was removed. The resulting Ga2O3 / TAPC heterojunction was then masked with a perforated mask, and a 5 nm thick Ti metal layer and a 45 nm thick Au metal layer were successively sputtered using magnetron sputtering to obtain a Ti / Au composite electrode with a diameter of 3 mm. The sputtering process conditions were as follows: after vacuuming, the cavity pressure was 1 × 10⁻⁶. 4 Pa, substrate temperature is room temperature, working atmosphere is Ar gas, working pressure is 1.2 Pa, sputtering power is 40 W, sputtering time of Ti metal layer is 1 minute, sputtering time of Au metal layer is 4 minutes, forming Ti / Au composite electrode, i.e., obtaining the first electrode and the second electrode, both of which are made of Ti / Au composite electrode.

[0045] The organic-inorganic hybrid heterojunction solar-blind photodetector prepared in this application embodiment has the following structure: Figure 1As shown, the electrode includes an Al2O3 substrate 1, a Ga2O3 light-absorbing layer 2, a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3, a first electrode 4, and a second electrode 5; wherein the Ga2O3 light-absorbing layer 2 is located on the Al2O3 substrate 1, the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is located on the side of the Ga2O3 light-absorbing layer 2 facing away from the Al2O3 substrate 1, and the area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is smaller than that of the Al2O3 substrate 1. The area of ​​the Ga2O3 light-absorbing layer 2 is such that the first electrode 4 is located on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 away from the Ga2O3 light-absorbing layer 2, and the second electrode 5 is located on the side of the Ga2O3 light-absorbing layer 2 away from the Al2O3 substrate 1. The first electrode 4 and the second electrode 5 are not in direct contact. The Ga2O3 light-absorbing layer 2 and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 form a heterojunction, which creates a built-in electric field that can separate photogenerated carriers.

[0046] In this design, both the first electrode 4 and the second electrode 5 are Ti / Au composite electrodes, comprising a Ti metal layer and an Au metal layer. The thickness of the Ti metal layer is 5 nm, and the thickness of the Au metal layer is 45 nm. Both the first electrode 4 and the second electrode 5 have a diameter of 30 nm. The Ga2O3 light-absorbing layer 2 has a thickness of 400 nm, and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 has a thickness of 200 nm. The area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is two-thirds the area of ​​the Ga2O3 light-absorbing layer 2.

[0047] The performance test results of the organic-inorganic hybrid heterojunction solar-blind photodetector are similar to those in Example 1.

[0048] Example 3

[0049] A method for fabricating an organic-inorganic hybrid heterojunction solar-blind photodetector includes the following steps:

[0050] A 10mm × 10mm × 0.5mm Al2O3 substrate with its C-side surface was used as a substrate. The substrate was sequentially immersed in acetone, ethanol, and deionized water, each ultrasonically cleaned for 10 minutes. After removal, it was rinsed with deionized water and finally dried with dry air to obtain the treated Al2O3 substrate, ready for use. The treated Al2O3 substrate was placed in a deposition chamber, and a Ga2O3 thin film was grown on the Al2O3 substrate using organometallic chemical vapor deposition (GMCVD). Trimethylgallium and oxygen were used as reactants, and the substrate temperature was 790℃, forming a Ga2O3 light-absorbing layer with a thickness of 400nm.

[0051] 10 mg of 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC) powder was dispersed in 1 ml of tetrahydrofuran solution and sonicated for 20 minutes to form a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution (TAPC solution), which was then set aside. One-third of the prepared Ga2O3 film was covered with heat-release tape, and 100 μL of TAPC solution was pipetted onto the uncovered area. The film was then rotated at 3000 r / min for 40 seconds to obtain a Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction. The obtained Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] heterojunction was heated on an 80°C heating stage for 20 minutes, and the heat-release tape was removed. The resulting Ga2O3 / TAPC heterojunction was then masked with a perforated mask, and a 15 nm thick Ti metal layer and a 55 nm thick Au metal layer were successively sputtered using magnetron sputtering to obtain a Ti / Au composite electrode with a diameter of 3 mm. The sputtering process conditions were as follows: after vacuuming, the cavity pressure was 1 × 10⁻⁶. 4 Pa, substrate temperature is room temperature, working atmosphere is Ar gas, working pressure is 1.2 Pa, sputtering power is 40 W, sputtering time of Ti metal layer is 3 minutes, sputtering time of Au metal layer is 6 minutes, forming Ti / Au composite electrode, i.e., obtaining the first electrode and the second electrode, both of which are made of Ti / Au composite electrode.

[0052] The organic-inorganic hybrid heterojunction solar-blind photodetector prepared in this application embodiment has the following structure: Figure 1As shown, the electrode includes an Al2O3 substrate 1, a Ga2O3 light-absorbing layer 2, a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3, a first electrode 4, and a second electrode 5; wherein the Ga2O3 light-absorbing layer 2 is located on the Al2O3 substrate 1, the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is located on the side of the Ga2O3 light-absorbing layer 2 facing away from the Al2O3 substrate 1, and the area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is smaller than that of the Al2O3 substrate 1. The area of ​​the Ga2O3 light-absorbing layer 2 is such that the first electrode 4 is located on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 away from the Ga2O3 light-absorbing layer 2, and the second electrode 5 is located on the side of the Ga2O3 light-absorbing layer 2 away from the Al2O3 substrate 1. The first electrode 4 and the second electrode 5 are not in direct contact. The Ga2O3 light-absorbing layer 2 and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 form a heterojunction, which creates a built-in electric field that can separate photogenerated carriers.

[0053] In this design, both the first electrode 4 and the second electrode 5 are Ti / Au composite electrodes, comprising a Ti metal layer and an Au metal layer. The thickness of the Ti metal layer is 15 nm, and the thickness of the Au metal layer is 45 nm. Both the first electrode 4 and the second electrode 5 have a diameter of 30 nm. The Ga2O3 light-absorbing layer 2 has a thickness of 400 nm, and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 has a thickness of 200 nm. The area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer 3 is two-thirds the area of ​​the Ga2O3 light-absorbing layer 2.

[0054] The performance test of the organic-inorganic hybrid heterojunction solar-blind photodetector is similar to that in Example 1.

[0055] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An organic-inorganic hybrid heterojunction solar-blind photodetector, characterized in that, The system comprises an Al2O3 substrate, a Ga2O3 light-absorbing layer, a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer, a first electrode, and a second electrode; wherein the Ga2O3 light-absorbing layer is located on the Al2O3 substrate, the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is located on the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate, and the area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is smaller than that of the first electrode and the second electrode. The area of ​​the a2O3 light-absorbing layer is such that the first electrode is located on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer away from the Ga2O3 light-absorbing layer, and the second electrode is located on the side of the Ga2O3 light-absorbing layer away from the Al2O3 substrate. The first electrode and the second electrode are not in direct contact. The Ga2O3 light-absorbing layer and the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer form a heterojunction, creating a built-in electric field that can separate photogenerated carriers.

2. The organic-inorganic hybrid heterojunction solar-blind photodetector according to claim 1, characterized in that, Both the first electrode and the second electrode are Ti / Au composite electrodes. The Ti / Au composite electrode includes a Ti metal layer and an Au metal layer. The thickness of the Ti layer is 5-15 nm, and the thickness of the Au layer is 45-55 nm.

3. The organic-inorganic hybrid heterojunction solar-blind photodetector according to claim 1, characterized in that, The thickness of the Ga2O3 light-absorbing layer is 400 nm, and the thickness of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is 200 nm.

4. The organic-inorganic hybrid heterojunction solar-blind photodetector according to claim 1, characterized in that, The area of ​​the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer is 2 / 3 of the area of ​​the Ga2O3 light-absorbing layer.

5. A method for preparing the organic-inorganic hybrid heterojunction solar-blind photodetector according to any one of claims 1-4, characterized in that, Includes the following steps: Using Al2O3 as a substrate, a Ga2O3 thin film is grown on the Al2O3 substrate by metal-organic chemical vapor deposition, using trimethylgallium and oxygen as reaction raw materials, and the substrate temperature is 790℃, thus forming a Ga2O3 light-absorbing layer. A shielding layer is formed on the side of the Ga2O3 light-absorbing layer away from the Al2O3 substrate, and the shielding layer covers a portion of the Ga2O3 light-absorbing layer; A 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution was spin-coated onto the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate to form a 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer. The shielding layer was then removed to form a Ga2O3 / 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] layer, constituting a heterojunction. Using a photomask, electrodes are fabricated on the side of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] opposite to the Ga2O3 light-absorbing layer and on the side of the Ga2O3 light-absorbing layer opposite to the Al2O3 substrate, respectively, to form a first electrode and a second electrode.

6. The method according to claim 5, characterized in that, The electrode fabrication process includes: sequentially sputtering a Ti metal layer with a thickness of 5-15 nm and an Au metal layer with a thickness of 45-55 nm using magnetron sputtering. The magnetron sputtering process conditions include: a cavity pressure of 1×10 after vacuuming. 4 Pa, substrate temperature is room temperature, working atmosphere is Ar gas, working pressure is 1.2 Pa, sputtering power is 40 W, sputtering time of Ti metal layer is 2 minutes, sputtering time of Au metal layer is 5 minutes.

7. The method according to claim 5, characterized in that, The shielding layer is heat-release adhesive tape. The removal of the shielding layer includes: heating on an 80°C heating table for 20 minutes to remove the heat-releasing tape.

8. The method according to claim 5, characterized in that, The spin coating conditions are: 500 r / min for 5 seconds; or / and 3000 r / min for 40 seconds.

9. The method according to claim 5, characterized in that, The preparation process of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] solution is as follows: 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] is dispersed in a tetrahydrofuran solution and sonicated for 20 minutes. The mass-to-volume ratio of the 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] to the tetrahydrofuran solution is 10 mg: 1 ml.

10. The method according to claim 5, characterized in that, The shielding layer covers one-third of the Ga2O3 light-absorbing layer; The Al2O3 substrate is pretreated by immersing it in acetone, ethanol and deionized water in sequence, sonicating it for 10 minutes each, rinsing it with deionized water, and finally drying it with dry air to obtain the pretreated Al2O3 substrate.

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