Cu2O / InGaN heterojunction visible light detector and preparation method and application thereof

Abstract

The invention provides a Cu2O / InGaN heterojunction visible light detector and a preparation method and application thereof.The light detector comprises a substrate, a buffer layer, an InGaN functional layer, a Cu2O layer and precious metal nano-particles located on the Cu2O layer, Cu2O and InGaN form an II-type heterojunction, a built-in electric field is built on a contact interface, photo-induced electrons are made to flow towards the InGaN direction quickly, and therefore the photoelectric conversion efficiency is improved. Effective separation and transportation of carriers are promoted, the light current and responsivity are increased, and the response speed is increased; and the precious metal nanoparticles positioned on the Cu2O layer are further in resonance coupling with InGaN, so that the number of photon-generated carriers is increased, the photoelectric coupling efficiency of the detector is improved, and the visible light detector is simple in structure, high in sensitivity and high in light response speed. And the device can be prepared by adopting existing preparation methods of some devices, can be directly produced, and is simple in preparation method, time-saving and efficient.

Description

Technical Field

[0001] The present application belongs to the technical field of visible light detectors, and in particular, relates to a Cu2O / InGaN heterojunction visible light detector and a preparation method thereof. Background Art

[0002] The third generation compound semiconductor InGaN has high quantum efficiency and good wavelength signal selection. By adjusting the doping amount of In, the band gap can be continuously adjusted in the range of 0.7eV to 3.4eV. The application of InGaN materials in visible light detectors can match the wavelength of incident light with the wavelength received by the detector, thereby receiving the optical signal to the greatest extent. InGaN also has high carrier mobility, low dielectric constant, and stable chemical and thermal properties, making it an ideal detector for the next generation of visible light communications.

[0003] There are many types of InGaN-based visible light detectors, including PIN, APD, MSM, and heterojunction detectors. Although PIN and APD detectors have excellent performance such as low dark current and fast response speed, they are complex in structure, cumbersome in process, and not easy to prepare. The MSM detector is composed of two back-to-back Schottky barriers. The preparation process of this type of detector is simple, no p-type doping and etching are required, and it is easy to integrate into a single chip. The distance between its metal interdigitated electrodes is very small, the junction capacitance is small, and the response speed is fast. However, the prominent problem of the MSM detector is the relatively high dark current and the quantum efficiency is not high enough. In recent years, research on InGaN-based visible light detectors based on heterojunctions has made certain progress.

[0004] Cu2O is a direct narrow-bandgap p-type semiconductor with a bandgap width ranging from 1.9 to 2.38 eV. It has a visible light response and is expected to match InGaN to construct a pn heterojunction structure and prepare a Cu2O / InGaN heterojunction visible light detector. Summary of the invention

[0005] The embodiment of the present application provides a Cu2O / InGaN heterojunction visible light detector and a preparation method and application thereof to solve the problems existing in the related technology. The technical solution is as follows:

[0006] In a first aspect, an embodiment of the present application provides a Cu2O / InGaN heterojunction visible light detector, comprising a substrate, a buffer layer, an InGaN functional layer, a Cu2O layer and a layer, and noble metal nanoparticles located on the Cu2O layer, which are arranged in sequence from bottom to top.

[0007] In one embodiment, it also includes a first metal electrode and a second metal electrode, the Cu2O layer covers a portion of the InGaN, the first metal electrode is located on the Cu2O, the second metal electrode is located on the InGaN, and the first metal electrode forms an ohmic contact with the Cu2O, and the second metal electrode forms an ohmic contact with the InGaN.

[0008] In one embodiment, the molar fraction of the In component in the InGaN functional layer is 5-70%.

[0009] In one embodiment, the thickness of the InGaN layer is 50-200 nm, the thickness of the Cu2O layer is 50-250 nm, and the thickness of the first metal electrode and the second metal electrode is 50-100 nm.

[0010] In one embodiment, the substrate is Si.

[0011] In one embodiment, the buffer layer is an AlN layer, an AlGaN layer or a GaN layer.

[0012] In one embodiment, the first metal electrode and the second metal electrode are respectively Ti, Au, Ni, Au, or a combination of two or more thereof.

[0013] In one embodiment, the noble metal nanoparticles are Au and / or Ag.

[0014] In a second aspect, an embodiment of the present application provides a method for preparing a Cu2O / InGaN heterojunction visible light detector, comprising the following steps:

[0015] Step S1, growing a buffer layer and an InGaN functional layer on a substrate;

[0016] Step S2, photolithography of a Cu2O window on the InGaN surface and preparation of a Cu2O layer;

[0017] Step S3, photolithography electrode positions on the surfaces of Cu2O and InGaN, and preparation of electrodes;

[0018] Step S4, performing photolithography on the Cu2O surface, using electron beam evaporation of metal film to evaporate a precious metal film, and then using a thermal annealing process to prepare precious metal nanoparticles on the surface to obtain the Cu2O / InGaN heterojunction visible light detector.

[0019] In one embodiment, pulsed laser deposition and molecular beam epitaxy are used to grow the buffer layer and the InGaN functional layer on the substrate.

[0020] In one embodiment, the preparation of the Cu2O layer in step S2 and the preparation of the electrode in step S3 are both carried out using a physical vapor deposition process.

[0021] In one embodiment, the physical vapor deposition process includes evaporation and sputtering.

[0022] In one embodiment, the photolithography in step S2, step S3 and step S4 includes the following steps: surface coating, pre-baking, exposure, post-baking, full exposure and development.

[0023] In one embodiment, the pre-baking and post-baking temperatures are 95-115° C., the drying times are 80-100 s respectively; the exposure time is 30-40 s; the full exposure time is 50-70 s; and the development time is 20-40 s.

[0024] In one embodiment, in step S4, the rate of evaporating the precious metal film by the electron beam evaporation method is 0.10-0.15 nm / min; the thickness of the precious metal film is 5-20 nm; and the thermal annealing temperature is 200-700°C.

[0025] In one embodiment, the substrate is cleaned before use by ultrasonic cleaning with acetone, ethanol and deionized water for 3-8 minutes in sequence to obtain a clean substrate.

[0026] In a third aspect, an embodiment of the present application provides an application of the Cu2O / InGaN heterojunction visible light detector in blue light detection.

[0027] The advantages or beneficial effects of the above technical solution include at least:

[0028] The present invention discloses a Cu2O / InGaN heterojunction visible light detector, which includes a substrate, a buffer layer, an InGaN functional layer, a Cu2O layer, and a noble metal nanoparticle located on the Cu2O layer. The structure is simple and the detector is a highly sensitive and high-speed light-response visible light detector. Cu2O and InGaN form a type II heterojunction, and a built-in electric field is constructed at the contact interface, so that photogenerated electrons flow faster toward the InGaN direction, promote the effective separation and transport of carriers, increase the photocurrent and responsiveness, and improve the response speed; and the noble metal nanoparticles located on the Cu2O layer further resonate and couple with InGaN, increase the number of photogenerated carriers, and improve the photoelectric coupling efficiency of the detector.

[0029] The present invention discloses a method for preparing a Cu2O / InGaN heterojunction visible light detector, which is prepared by adopting some existing device preparation methods and can be directly produced. The preparation method is simple, time-saving and efficient.

[0030] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0032] Figure 1 A schematic cross-sectional view of the structure of a Cu2O / InGaN heterojunction visible light detector prepared according to an embodiment of the present invention; wherein 1 represents a Si substrate; 2 represents a buffer layer; 3 represents an InGaN functional layer; 4 represents a Cu2O layer; 5 represents a metal layer electrode; and 6 represents a noble metal nanoparticle;

[0033] Figure 2 The dark current curve of the Cu2O / InGaN heterojunction visible light detector prepared in Example 1 and the dark current curve of the MSM type and heterojunction type InGaN visible light detectors prepared in Comparative Examples 1 and 2;

[0034] Figure 3 The spectral response curve of the Cu2O / InGaN heterojunction visible light detector prepared in Example 1 and the spectral response curve of the MSM type and heterojunction type InGaN visible light detectors prepared in Comparative Examples 1 and 2;

[0035] Figure 4 The IT curve of the Cu2O / InGaN heterojunction visible light detector prepared in Example 1;

[0036] Figure 5 The IT curve of the MSM type InGaN visible light detector prepared in Comparative Example 1;

[0037] Figure 6 This is the IT curve of the Cu2O / InGaN heterojunction visible light detector without nanoparticles prepared in Comparative Example 2. DETAILED DESCRIPTION

[0038] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0039] An embodiment of the present application provides a Cu2O / InGaN heterojunction visible light detector, comprising a substrate, a buffer layer, an InGaN functional layer, a Cu2O layer and a layer, and noble metal nanoparticles located on the Cu2O layer, which are arranged in sequence from bottom to top.

[0040] Cu2O is a direct narrow bandgap p-type semiconductor with a bandgap width ranging from 1.9 to 2.38 eV. It has visible light response and can be matched with InGaN to construct a pn heterojunction structure. Cu2O and InGaN form a type II heterojunction, and a built-in electric field is constructed at the contact interface, which accelerates the flow of photogenerated electrons toward InGaN, promotes the effective separation and transport of carriers, increases photocurrent and responsiveness, and improves response speed. Precious metal nanoparticles are further arranged on the Cu2O layer, and the precious metal nanoparticles further resonate with InGaN to increase the number of photogenerated carriers and improve the photoelectric coupling efficiency of the detector. The overall high-speed transport of carriers and the enhancement of the light absorption efficiency of the detector are achieved.

[0041] As one implementation method, Figure 1 As shown, the Cu2O / InGaN heterojunction visible light detector also includes a first metal electrode and a second metal electrode, the Cu2O layer covers a portion of the InGaN, the first metal electrode is located on the Cu2O, the second metal electrode is located on the InGaN, and the first metal electrode forms an ohmic contact with the Cu2O, and the second metal electrode forms an ohmic contact with the InGaN.

[0042] As one implementation method, the molar fraction of the In component in the InGaN functional layer is 5-70%. By adjusting the doping amount of In, the band gap can be continuously adjusted.

[0043] As one embodiment, the thickness of the InGaN layer is 50-200nm, the thickness of the Cu2O layer is 50-250nm, and the thickness of the first metal electrode and the second metal electrode is 50-100nm. Preferably, the thickness of the InGaN layer is 100nm, the thickness of the Cu2O layer is 150nm, and the thickness of the first metal electrode and the second metal electrode is 90nm.

[0044] As one embodiment, the substrate is Si.

[0045] As one embodiment, the buffer layer is an AlN layer, an AlGaN layer or a GaN layer.

[0046] As one embodiment, the first metal electrode and the second metal electrode are respectively Ti, Au, Ni, Au, or a combination of two or more thereof.

[0047] As one embodiment, the noble metal nanoparticles are Au and / or Ag.

[0048] The present application provides a method for preparing a Cu2O / InGaN heterojunction visible light detector, comprising the following steps:

[0049] Step S1, growing a buffer layer and an InGaN functional layer on a substrate;

[0050] Step S2, photolithography of a Cu2O window on the InGaN surface and preparation of a Cu2O layer;

[0051] Step S3, photolithography electrode positions on the surfaces of Cu2O and InGaN, and preparation of electrodes;

[0052] Step S4, performing photolithography on the Cu2O surface, using electron beam evaporation of metal film to evaporate a precious metal film, and then using a thermal annealing process to prepare precious metal nanoparticles on the surface to obtain the Cu2O / InGaN heterojunction visible light detector.

[0053] As one embodiment, before step S1, the substrate is cleaned by ultrasonic cleaning with acetone, ethanol and deionized water in sequence for 3-8 minutes to obtain a clean substrate.

[0054] As one of the implementation methods, when growing a buffer layer on a substrate, pulsed laser deposition is used to grow the buffer layer, and molecular beam epitaxy is used to grow an InGaN layer. When the buffer layer is an AlN layer, an AlGaN layer, or a GaN layer, pulsed laser deposition can be used to grow a buffer layer of a certain thickness, and molecular beam epitaxy can be used to grow an InGaN layer, and the thickness of the InGaN layer is 50 to 200 nm.

[0055] As one implementation method, a Cu2O layer is provided on the InGaN surface, and the Cu2O layer is prepared on the InGaN surface by a physical vapor deposition process. The physical vapor deposition process includes evaporation and sputtering. Before physical vapor deposition, a Cu2O window needs to be photolithographically formed on the InGaN surface.

[0056] As one of the embodiments, photolithography includes the following steps: surface coating, pre-baking, exposure, post-baking, full exposure and development; the specific preparation parameters are: the temperature of the pre-baking and post-baking is 95-115°C, and the drying time is 80-100s respectively; the exposure time is 30-40s; the full exposure time is 50-70s; and the development time is 20-40s.

[0057] As one of the implementation modes, the Cu2O layer covers a portion of the InGaN.

[0058] As one embodiment, the Cu2O layer covers a portion of InGaN; there are two metal electrodes, namely a first metal electrode and a second metal electrode, the first metal electrode is located on the Cu2O, the second metal electrode is located on the InGaN, and the first metal electrode forms an ohmic contact with the Cu2O, and the second metal electrode forms an ohmic contact with the InGaN.

[0059] As one embodiment, the metal electrode is prepared by a physical vapor deposition process. Similarly, in this embodiment, the physical vapor deposition process includes evaporation and sputtering; before the physical vapor deposition electrode, it is necessary to first photolithographically form electrode windows on the InGaN surface and Cu2O.

[0060] As one of the embodiments, the photolithography electrode window includes the following steps: surface coating, pre-baking, exposure, post-baking, full exposure and development; the specific preparation parameters are: the pre-baking and post-baking temperatures are 95-115°C, and the drying times are 80-100s respectively; the exposure time is 30-40s; the full exposure time is 50-70s; and the development time is 20-40s.

[0061] As one embodiment, the noble metal nanoparticles are prepared by first preparing a noble metal film and then performing a thermal annealing process. In this embodiment, the noble metal is Au and / or Ag, and the noble metal film is deposited by electron beam evaporation.

[0062] The electron beam evaporation method evaporates the precious metal film at a rate of 0.10-0.15 nm / min, and the thickness of the evaporated precious metal film is 5-20 nm, and then undergoes thermal annealing at 200-700° C. The precious metal film forms precious metal nanoparticles.

[0063] The following is a further description with reference to specific embodiments.

[0064] Example 1

[0065] This embodiment provides a Cu2O / InGaN heterojunction visible light detector, such as Figure 1 As shown, the structure includes Si substrate 1, AlN buffer layer 2, InGaN functional layer 3, Cu2O layer 4, metal layer electrode 5 and Ag nanoparticles 6 from bottom to top; the Ag nanoparticles are located on the Cu2O layer not covered by the metal layer electrode; the Cu2O layer covers part of the InGaN, the thickness of the InGaN layer 3 is 100nm, and the thickness of the Cu2O layer 4 is 150nm;

[0066] The Cu2O / InGaN heterojunction visible light detector is prepared by a method comprising the following steps:

[0067] Acetone, ethanol and deionized water were used for ultrasonic cleaning for 5 min in sequence to obtain a clean Si substrate;

[0068] An AlN buffer layer was grown on a Si substrate using pulsed laser deposition, and a 100nm thick InGaN layer was grown using molecular beam epitaxy.

[0069] A Cu2O window was photolithographically formed on the surface of the InGaN functional layer using a negative resist process, and a 150nm thick Cu2O layer was prepared using an evaporation process at a speed of 0.10nm / min.

[0070] The electrode positions were photolithographically formed on the Cu2O / InGaN surface using a negative photoresist process, and Au electrodes were sputtered on the Cu2O and InGaN surfaces not covered with Cu2O using a sputtering process, with a thickness of 90nm respectively.

[0071] The position of the Ag metal film is photoetched on the Cu2O surface by using a negative resist process, and a 10nm thick Ag film is evaporated at 0.10nm / min by using an electron beam evaporation metal film process, and an annealing treatment is performed at 300°C after the evaporation is completed; thereby obtaining the Cu2O / InGaN heterojunction visible light detector;

[0072] In the preparation process, the steps of negative photoresist process include: surface photoresist, pre-baking at 105°C for 95 seconds, exposure for 35 seconds, post-baking for 90 seconds, full exposure for 60 seconds and development for 30 seconds.

[0073] Example 2

[0074] This embodiment provides a Cu2O / InGaN heterojunction visible light detector, such as Figure 1 As shown, the structure includes Si substrate 1, AlGaN buffer layer 2, InGaN functional layer 3, Cu2O layer 4, metal layer electrode 5 and Ag nanoparticles 6 from bottom to top; the Ag nanoparticles are located on the Cu2O layer not covered by the metal layer electrode; the Cu2O layer covers part of the InGaN, the thickness of the InGaN layer 3 is 50nm, and the thickness of the Cu2O layer 4 is 50nm;

[0075] The Cu2O / InGaN heterojunction visible light detector is prepared by a method comprising the following steps:

[0076] Acetone, ethanol and deionized water were used for ultrasonic cleaning for 5 min in sequence to obtain a clean Si substrate;

[0077] An AlGaN buffer layer was grown on a Si substrate using pulsed laser deposition, and a 50nm thick InGaN layer was grown using molecular beam epitaxy;

[0078] A Cu2O window was photolithographically formed on the surface of the InGaN functional layer using a negative resist process, and a 50nm thick Cu2O layer was deposited at a speed of 0.15nm / min using an evaporation process.

[0079] The electrode positions were photolithographically formed on the Cu2O / InGaN surface using a negative photoresist process, and Au electrodes were sputtered on the Cu2O and InGaN surfaces not covered with Cu2O using a sputtering process, with a thickness of 60nm respectively.

[0080] The position of the Ag metal film is photoetched on the Cu2O surface by using a negative resist process, and a 5nm thick Ag film is evaporated at 0.15nm / min by using an electron beam evaporation metal film process, and an annealing treatment is performed at 700°C after the evaporation is completed; thereby obtaining the Cu2O / InGaN heterojunction visible light detector;

[0081] In the preparation process, the steps of negative photoresist process include: surface photoresist, pre-baking at 95°C for 100 seconds, exposure for 30 seconds, post-baking for 80 seconds, full exposure for 50 seconds and development for 20 seconds.

[0082] Example 3

[0083] This embodiment provides a Cu2O / InGaN heterojunction visible light detector, such as Figure 1 As shown, the structure includes Si substrate 1, GaN buffer layer 2, InGaN functional layer 3, Cu2O layer 4, metal layer electrode 5 and Ag nanoparticles 6 from bottom to top; the Ag nanoparticles are located on the Cu2O layer not covered by the metal layer electrode; the Cu2O layer covers part of the InGaN, the thickness of the InGaN layer 3 is 200nm, and the thickness of the Cu2O layer 4 is 250nm;

[0084] The Cu2O / InGaN heterojunction visible light detector is prepared by a method comprising the following steps:

[0085] Acetone, ethanol and deionized water were used for ultrasonic cleaning for 5 min in sequence to obtain a clean Si substrate;

[0086] The GaN buffer layer was grown on the Si substrate by pulsed laser deposition, and the 200nm thick InGaN layer was grown by molecular beam epitaxy;

[0087] A Cu2O window was photolithographically formed on the surface of the InGaN functional layer using a negative resist process, and a 250nm thick Cu2O layer was prepared using an evaporation process at a rate of 0.15nm / min.

[0088] The electrode positions were photolithographically formed on the Cu2O / InGaN surface using a negative photoresist process, and Ag electrodes were sputtered on the Cu2O surface and Au electrodes were sputtered on the InGaN surface not covered with Cu2O using a sputtering process, with a thickness of 75nm respectively.

[0089] The position of the Ag metal film is photoetched on the Cu2O surface by using a negative resist process, and a 20nm thick Ag film is evaporated at 0.15nm / min by using an electron beam evaporation metal film process, and an annealing treatment is performed at 200°C after the evaporation is completed; thereby obtaining the Cu2O / InGaN heterojunction visible light detector;

[0090] In the preparation process, the steps of negative photoresist process include: surface photoresist, pre-baking at 115°C for 80 seconds, exposure for 40 seconds, post-baking for 100 seconds, full exposure for 70 seconds and development for 40 seconds.

[0091] Comparative Example 1

[0092] Comparative Example 1 provides an MSM type InGaN visible light detector, the composition and preparation method of which are the same as those of Example 1, except that the Cu2O layer and Ag nanoparticles in Example 1 are removed.

[0093] Comparative Example 2

[0094] Comparative Example 2 provides a Cu2O / InGaN heterojunction visible light detector, the composition and preparation method of which are the same as those of Example 1, except that the Ag nanoparticles in Example 1 are removed.

[0095] Performance Testing:

[0096] The Cu2O / InGaN heterojunction visible light detector prepared in Example 1 and the MSM type and heterojunction type InGaN visible light detectors prepared in Comparative Examples 1 and 2 were tested for dark current at -1 to 1V. The dark current curve of the visible light detector is shown in FIG. Figure 2 As shown;

[0097] from Figure 2 It can be seen that under a reverse bias voltage of -1 V, the dark current of the Cu2O / InGaN heterojunction visible light detector prepared in Example 1 is 4.27×10 -8 A, compared with the dark current of the MSM type InGaN visible light detector prepared in Example 1, 2.65×10 -7 A is one order of magnitude lower, but the dark current of the Cu2O / InGaN heterojunction visible light detector prepared in Comparative Example 2 without nanoparticles is 2.37×10 -8 A is high, indicating that the construction of Cu2O / InGaN heterojunction promotes lateral carrier transport, reduces carrier recombination, and can reduce the dark current of the device. However, due to the influence of thermal ion emission and tunnel current, the dark current of the nanoparticle-enhanced device will be slightly increased.

[0098] The spectral response test was conducted on the Cu2O / InGaN heterojunction visible light detector prepared in Example 1 and the MSM type and heterojunction type InGaN visible light detectors prepared in Comparative Examples 1 and 2. The visible spectrum response curve is shown in FIG. Figure 3 As shown;

[0099] Figure 3 It shows that the Cu2O / InGaN heterojunction visible light detector prepared in Example 1 has a peak responsivity of 0.762A / W at 420nm, the MSM-type InGaN visible light detector prepared in Comparative Example 1 has a peak responsivity of 0.166A / W at 420nm, and the Cu2O / InGaN heterojunction visible light detector without nanoparticles prepared in Comparative Example 2 has a peak responsivity of 0.547A / W at 420nm, indicating that heterojunction devices have higher spectral response and higher quantum efficiency in the blue-violet light band, and the nanoparticle-enhanced Cu2O / InGaN heterojunction device has a higher responsivity.

[0100] The Cu2O / InGaN heterojunction visible light detector prepared in Example 1 and the MSM type and heterojunction type InGaN visible light detectors prepared in Comparative Examples 1 and 2 were tested for IT curves. The IT curve of the Cu2O / InGaN heterojunction visible light detector prepared in Example 1 is shown in FIG. Figure 4 As shown; the IT curve of the MSM type InGaN visible light detector prepared in Comparative Example 1 is as shown Figure 5 As shown; the IT curve of the Cu2O / InGaN heterojunction visible light detector without nanoparticles prepared in Comparative Example 2 is as shown Figure 6 shown.

[0101] Depend on Figure 4 It can be seen that under 420nm wavelength light irradiation and -1V reverse bias, the rise / fall time of the Cu2O / InGaN heterojunction visible light detector is 15.1 / 9.6ms.

[0102] Depend on Figure 5 It can be seen that under 420nm wavelength light irradiation and -1V reverse bias, the rise / fall time of the MSM type InGaN visible light detector is 52.6 / 194.1ms.

[0103] Depend on Figure 6 It can be seen that under 420nm wavelength light irradiation and -1V reverse bias, the rise / fall time of the Cu2O / InGaN heterojunction visible light detector without nanoparticles is 43.1 / 104.6ms. The results show that compared with the MSM type and heterojunction InGaN visible light detectors, the prepared nanoparticle enhanced Cu2O / InGaN heterojunction visible light detector has a faster response speed.

[0104] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0105] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0106] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A Cu2O / InGaN heterojunction visible light detector, characterized in that: The invention comprises a substrate, a buffer layer, an InGaN functional layer, a Cu2O layer and noble metal nanoparticles located on the Cu2O layer, which are arranged in sequence from bottom to top.

2. The Cu2O / InGaN heterojunction visible light detector according to claim 1, characterized in that: It also includes a first metal electrode and a second metal electrode, the Cu2O layer covers a portion of the InGaN, the first metal electrode is located on the Cu2O, the second metal electrode is located on the InGaN, and the first metal electrode forms an ohmic contact with the Cu2O, and the second metal electrode forms an ohmic contact with the InGaN.

3. A Cu2O / InGaN heterojunction visible light detector according to claim 1 or 2, characterized in that: The molar fraction of the In component in the InGaN functional layer is 5 to 70%; The thickness of the InGaN layer is 50-200 nm, the thickness of the Cu2O layer is 50-250 nm, and the thickness of the first metal electrode and the second metal electrode is 50-100 nm.

4. A Cu2O / InGaN heterojunction visible light detector according to claim 1 or 2, characterized in that: The substrate is Si; the buffer layer is an AlN layer, an AlGaN layer or a GaN layer; The first metal electrode and the second metal electrode are respectively Ti, Au, Ni, Au, or a combination of two or more thereof; The noble metal nanoparticles are Au and / or Ag.

5. A method for preparing a Cu2O / InGaN heterojunction visible light detector, characterized in that: The following steps are involved: Step S1, growing a buffer layer and an InGaN functional layer on a substrate; Step S2, photolithography of a Cu2O window on the InGaN surface and preparation of a Cu2O layer; Step S3, photolithography electrode positions on the surfaces of Cu2O and InGaN, and preparation of electrodes; Step S4, performing photolithography on the Cu2O surface, using electron beam evaporation of metal film to evaporate a precious metal film, and then using a thermal annealing process to prepare precious metal nanoparticles on the surface to obtain the Cu2O / InGaN heterojunction visible light detector.

6. The method for preparing a Cu2O / InGaN heterojunction visible light detector according to claim 5, characterized in that: The buffer layer and InGaN functional layer are grown on the substrate using pulsed laser deposition and molecular beam epitaxy; The preparation of the Cu2O layer in step S2 and the preparation of the electrode in step S3 are both carried out using a physical vapor deposition process; The physical vapor deposition process includes evaporation and sputtering.

7. The method for preparing a Cu2O / InGaN heterojunction visible light detector according to claim 5, characterized in that: In step S2, step S3 and step S4, the photolithography The process includes the following steps: surface coating, pre-baking, exposure, post-baking, full exposure and development; The temperatures of the pre-baking and post-baking are 95-115° C., and the drying times are 80-100 seconds respectively; the exposure time is 30-40 seconds; the full exposure time is 50-70 seconds; and the development time is 20-40 seconds.

8. The method for preparing a Cu2O / InGaN heterojunction visible light detector according to claim 5, characterized in that: In step S4, the rate of evaporating the precious metal film by the electron beam evaporation method is 0.10-0.15 nm / min; the thickness of the precious metal film is 5-20 nm; and the thermal annealing temperature is 200-700°C.

9. The method for preparing a Cu2O / InGaN heterojunction visible light detector according to claim 5, characterized in that: The substrate was cleaned before use by ultrasonic cleaning with acetone, ethanol and deionized water for 3-8 minutes in sequence to obtain a clean substrate.

10. Application of the Cu2O / InGaN heterojunction visible light detector according to any one of claims 1 to 9 in blue light detection.

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