Two-dimensional MoSe2, photoelectric detector and preparation method thereof

Abstract

The application discloses a two-dimensional MoSe2, a photoelectric detector and a preparation method thereof; the two-dimensional MoSe2 is prepared by using chemical vapor deposition method under a low-pressure atmosphere, with MoO3 and Se as precursors, and NaCl is further added into the MoO3; the photoelectric detector comprises, from bottom to top, a substrate, a buffer layer, a GaN layer, a MoSe2 functional layer and a Ti / Au metal layer electrode, wherein the Ti / Au metal layer electrode is arranged at two ends of the upper surface of the MoSe2 functional layer. The application uses NaCl assisted low-pressure chemical vapor deposition to realize the growth of large-size single-crystal two-dimensional MoSe2 by a relatively simple process, effectively improves the interface quality, shortens the migration path of carriers by constructing a two-dimensional / three-dimensional mixed-dimensional heterojunction, and improves the separation efficiency of the carriers, so that the light response capability of the photoelectric detector is enhanced, and the light absorption spectrum is enlarged.

Description

Technical Field

[0001] This invention relates to the field of photodetector technology, specifically to a two-dimensional MoSe2, a photodetector, and a method for its fabrication. Background Technology

[0002] MoSe2 is a layered compound, a typical transition metal sulfide. In MoSe2, the Mo atomic facets are sandwiched between two S atomic faces, forming a sandwich-like structure. This layered structure makes it possible to obtain two-dimensional MoSe2, a two-dimensional material composed of one or more layers of MoSe2. It not only possesses unique properties of two-dimensional materials, such as the quantum confinement effect, but also shares similar physical properties with other two-dimensional transition metal sulfides like MoS2, such as tunable band structure, excellent mechanical properties, high light absorption, and strong photoluminescence. Furthermore, compared to other transition metal sulfides, two-dimensional MoSe2 exhibits stronger absorption of the solar spectrum. These physical properties make two-dimensional MoSe2 photodetectors highly promising. However, the exciton effect inherent in two-dimensional materials hinders the separation of photogenerated carriers in MoSe2, and its relatively thin thickness also limits its light absorption, which greatly restricts the application of MoSe2 photodetectors.

[0003] On the other hand, due to GaN's wide bandgap, high critical breakdown field strength, and highly stable physicochemical properties, it can achieve efficient ultraviolet light emission and detection, enabling photodetectors made from GaN to operate in various extreme environments. Furthermore, the lattice mismatch between MoSe2 and GaN is relatively small, and the absence of dangling bonds on the surface of two-dimensional MoSe2 means that MoSe2 and GaN are connected by van der Waals forces, further reducing the impact of lattice mismatch on the interface quality of two-dimensional MoSe2. In photodetectors, two-dimensional / three-dimensional hybrid van der Waals heterojunctions can shorten carrier migration paths, improve carrier separation efficiency, and overcome the inherent defects of two-dimensional materials, such as limited light absorption. This improves the photodetector's photoresponse and on / off current ratio, and broadens the absorption spectrum, thus fully leveraging the advantages of both MoSe2 and GaN materials.

[0004] Currently, the fabrication methods for mixed-dimensional van der Waals heterojunctions of two-dimensional transition metal sulfides and GaN mainly rely on mechanical and liquid-phase exfoliation methods. These methods are complex and difficult to scale up for mass production, limiting the industrial application of two-dimensional materials. On the other hand, conventional semiconductor fabrication processes such as sputtering or evaporation are insufficient for fabricating low-layer-count single-crystal MoSe2, and the interface quality of heterojunctions prepared by these processes is not high. While chemical vapor deposition (CVD) is simple and compatible with existing semiconductor manufacturing processes, it is limited by the surface defect density and roughness of GaN substrates, making it difficult to directly grow large-size single-crystal two-dimensional MoSe2 on GaN, thus restricting the further development of mixed-dimensional heterojunction photodetectors. Summary of the Invention

[0005] To address the problems existing in two-dimensional MoSe2 / GaN heterojunction photodetectors and fully leverage the advantages of two-dimensional MoSe2 and GaN materials, this invention provides a two-dimensional MoSe2 and two-dimensional MoSe2 / GaN heterojunction photodetector with simple processing and high material quality, as well as its fabrication method.

[0006] The technical solution of this invention is:

[0007] A method for preparing two-dimensional MoSe2 includes the following steps:

[0008] Two-dimensional MoSe2 was grown on a substrate using chemical vapor deposition under a low-pressure atmosphere with MoO3 and Se as precursors; NaCl was also added to the MoO3; the pressure of the low-pressure atmosphere was 1000-5000 Pa.

[0009] Preferably, the growth of two-dimensional MoSe2 is carried out under a protective atmosphere; the pressure of the protective atmosphere is 1000-5000 Pa; and the gas flow rate of the protective atmosphere is 60-80 sccm.

[0010] More preferably, the protective gas in the protective atmosphere flow is argon.

[0011] More preferably, the protective atmosphere flows from Se to MoO3.

[0012] Preferably, a vacuum is drawn before the growth of two-dimensional MoSe2, and then a protective gas is introduced for gas washing; the vacuum degree of the vacuum drawing is 1 to 10-2 Pa;

[0013] Further preferred, the protective gas is argon.

[0014] Preferably, the substrate is GaN;

[0015] Preferably, the mass ratio of MoO3 to NaCl is 1:0.7 to 1:1;

[0016] Preferably, the mass ratio of Se to MoO3 is 40:1 to 48:1.

[0017] Preferably, the MoO3 and the matrix are in the upper temperature zone; the temperature of the upper temperature zone is 750-800°C; the Se is in the lower temperature zone; the temperature of the lower temperature zone is 400-450°C.

[0018] Preferably, the heat preservation time for growing two-dimensional MoSe2 is 10 to 15 minutes.

[0019] The two-dimensional MoSe2 prepared by the above method.

[0020] Preferably, the two-dimensional MoSe2 has one or two atomic layers.

[0021] A two-dimensional MoSe2 / GaN heterojunction photodetector includes, from bottom to top, a substrate, a buffer layer, a GaN layer, a MoSe2 functional layer, and a Ti / Au metal layer electrode. The Ti / Au metal layer electrode is located at both ends of the upper surface of the MoSe2 functional layer, which is the aforementioned two-dimensional MoSe2.

[0022] Preferably, the substrate is one of sapphire and Si;

[0023] Preferably, the buffer layer is an AlN layer grown on a substrate, and the thickness of the AlN layer is 200-300 nm;

[0024] Preferably, the GaN layer is an n-type polar GaN thin film of 2-3 μm;

[0025] Preferably, the Ti / Au metal layer consists of a Ti metal layer with a thickness of 30-50 nm and an Au metal layer with a thickness of 100-120 nm arranged sequentially from bottom to top.

[0026] The fabrication method of the above-mentioned two-dimensional MoSe2 / GaN heterojunction photodetector includes the following steps:

[0027] Step 1: A buffer layer is grown on the substrate using metal oxide chemical vapor deposition, followed by the growth of a GaN layer on the buffer layer;

[0028] Step 2: Using MoO3 and Se as precursors, two-dimensional MoSe2 is grown on the GaN layer prepared in Step 1 using low-pressure chemical vapor deposition; NaCl is also added to the MoO3.

[0029] Step 3: Use photolithography combined with vapor deposition to fabricate Ti / Au electrodes at both ends of the MoSe2 functional layer.

[0030] Preferably, the temperature of the growth buffer layer in step 1 is 1000–1300°C; the temperature of the GaN layer growth is 1100–1400°C.

[0031] Preferably, the photolithography in step 3 includes spin coating, drying, exposure and development; the spin coating speed is 2500-3000 r / min, the spin coating time is 25-30s, the drying time is 40-50s, the exposure time is 25-30s, and the development time is 40-45s.

[0032] Preferably, the evaporation rate in step 3 is 0.1 to 0.2 nm / min.

[0033] The beneficial effects of this invention are:

[0034] (1) The two-dimensional MoSe2 nanomaterials grown by this invention have the advantages of large size, low layer number, and simple process. In the growth process of two-dimensional MoSe2, NaCl is used to assist growth to reduce the melting point of MoO3, so that the Mo source can participate in vapor deposition more quickly. The gas pressure is reduced during the growth process to reduce the obstacle effect of the carrier gas on the precursor. The single-crystal two-dimensional material ensures the interface quality of the heterojunction, so that the characteristics of two-dimensional MoSe2 and GaN can be fully combined.

[0035] (2) The process for preparing two-dimensional MoSe2 / GaN heterostructures in this invention is compatible with existing semiconductor processes, enabling low-cost mass production. Furthermore, GaN with low lattice mismatch with MoSe2 is selected for chemical vapor deposition, which reduces defects and dislocation density caused by interfacial reactions and improves material quality.

[0036] (3) The two-dimensional MoSe2 / GaN hybrid heterostructure designed in this invention can improve the carrier separation efficiency, reduce the detector response time and improve the photo-dark current ratio, overcome the inherent defects of two-dimensional materials, thereby improving the optical response and switching current ratio of the device, and can expand the optical absorption spectrum, giving full play to the advantages of both MoSe2 and GaN materials. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the photodetector of the present invention;

[0038] Figure 2 This is a top view of the photodetector of the present invention;

[0039] Figure 3 These are optical microscope images of the MoSe2 / GaN heterojunction constructed in Example 1;

[0040] Figure 4 This is the Raman spectrum of the MoSe2 / GaN heterojunction constructed in Example 1;

[0041] Figure 5 The IV curve is the photodetector prepared in Example 1;

[0042] Figure 6 This is an optical microscope image of the MoSe2 / GaN heterojunction constructed in Comparative Example 1;

[0043] Figure 7 The image shows the Raman spectrum of the MoSe2 / GaN heterojunction constructed in Comparative Example 1.

[0044] Figure 1 , 2 middle:

[0045] 1 Substrate, 2 Buffer layer, 3 GaN layer, 4 MoSe2 functional layer, 5 Ti / Au metal electrode layer. Detailed Implementation

[0046] To clarify the technical solutions and advantages of the embodiments, the technical solutions of the present invention will be further explained and described below in conjunction with the embodiments and accompanying drawings. It should be noted that the specific embodiments described in this invention are only a part of the embodiments of the present invention, and the implementation of the present invention is not limited thereto.

[0047] like Figure 1 , 2 As shown, the present invention provides a two-dimensional MoSe2 / GaN photodetector, comprising 1... Substrate, 2 Buffer layer, 3 GaN layer, 4 MoSe2 functional layer, 5 Ti / Au metal electrode layer.

[0048] Wherein: the substrate 1 is sapphire or Si, with a thickness of 400-500 μm.

[0049] The buffer layer 2 is AlN grown on the substrate, and the thickness of the AlN layer is 200-300 nm.

[0050] The GaN layer 3 is an n-type polar GaN thin film covering the buffer layer 2, with a thickness of 2 to 3 μm.

[0051] The MoSe2 functional layer 4 covers the surface of the GaN layer 3, and the number of atomic layers is 1 or 2.

[0052] The Ti / Au metal electrode layer 5 covers the edge of the MoSe2 functional layer 4, and Ti metal layer with a thickness of 30-50 nm and Au metal layer with a thickness of 100-120 nm are arranged sequentially from bottom to top.

[0053] from Figure 2 It can be seen that the widths of substrate 1, buffer layer 2, and GaN layer 3 are all the same. The width of GaN layer 3 is slightly larger than the width of MoSe2 functional layer 4, and the width of Ti / Au metal electrode layer 5 is slightly smaller than the width of MoSe2 functional layer 4.

[0054] The fabrication method of the two-dimensional MoSe2 / GaN heterojunction photodetector includes the following steps:

[0055] Step 1: Using trimethylaluminum (TMAl) as the Al source and trimethylgallium (TMGa) as the Ga source, a thick AlN buffer layer and a GaN layer are sequentially grown on the substrate using metal oxide chemical vapor deposition.

[0056] Step 2: Using a mixture of MoO3 and NaCl powder as the Mo source and Se powder as the Se source, MoSe2 is grown by chemical vapor deposition on the sample obtained in Step 1. After the quartz tube is evacuated to a vacuum, argon gas is introduced for purging. After purging, the gas pressure inside the quartz tube is reduced, and protective gas is introduced into the tube furnace. Then, the two temperature zones are heated until the growth temperature is reached, and growth begins.

[0057] Step 3: Photolithography (spinning, drying, exposure and development) is used on the sample obtained in Step 2 to obtain the evaporation area of ​​the Ti / Au metal layer electrode, and Ti / Au metal electrode layer electrodes are prepared at both ends of the MoSe2 functional layer by electron beam evaporation.

[0058] Example 1:

[0059] This embodiment provides a method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector, the method comprising:

[0060] Step 1: On a 400 μm thick Si substrate, a 200 nm AlN buffer layer is grown on the substrate using trimethylaluminum (TMAl) as the Al source by metal oxide chemical vapor deposition. Subsequently, a 2 μm GaN layer is grown on the buffer layer using trimethylgallium (TMGa). The growth temperature is set to 1300 °C.

[0061] Step 2: Place the mixed powder of 5 mg MoO3 and 5 mg NaCl and the sample obtained in Step 1 in a quartz boat and send it into the upper temperature zone of a tube furnace. Send 200 mg Se powder into the lower temperature zone of the tube furnace. Pump the gas pressure in the quartz tube to 10-2 Pa, and then pass argon gas into the quartz tube for purging. After purging, reduce the gas pressure to 1000 Pa and control the argon gas flow rate at 80 sccm (argon gas flows from the lower temperature zone to the upper temperature zone). Heat the two temperature zones, with the upper temperature zone reaching 800℃ and the lower temperature zone reaching 400℃. Hold the temperature for 10 minutes for growth. After growth, use Raman spectroscopy to analyze the atomic layer number and chemical composition.

[0062] Step 3: Spin coat the MoSe2 functional layer of the sample obtained in Step 2 at a speed of 3000 r / min for 30 s, then dry for 50 s. Align the designated area of ​​the mask with the two ends of the MoSe2 functional layer and expose for 30 s. Finally, develop for 45 s. Then, deposit the Ti / Au metal layer on the sample surface by vapor deposition at a rate of 0.2 nm / min.

[0063] The two-dimensional MoSe2 / GaN photodetector prepared in this embodiment is as follows: Figure 1 , 2 As shown, the buffer layer has a thickness of 200 nm, the GaN layer has a thickness of 2 μm, the two-dimensional MoSe2 layer has one layer, and the Ti and Au metal layers have thicknesses of 40 nm and 100 nm, respectively.

[0064] Figure 3 This is an optical microscope image of the two-dimensional MoSe2 / GaN heterojunction grown in this embodiment. The dark area is the two-dimensional MoSe2 grown on GaN, and the light area is the surface of the uncovered GaN layer. It can be seen that this embodiment successfully grew a 50μm×50μm two-dimensional MoSe2 on GaN, which is relatively large in size.

[0065] Figure 4 The image shows the Raman spectrum of the two-dimensional MoSe2 / GaN heterojunction grown in this embodiment, with the value at 237.4 cm⁻¹. -1 The peak at that point represents the interlayer vibration mode of two-dimensional MoSe2 (A 1g ), 284.5cm -1 The peak at that point represents the in-plane vibrational mode (E) of two-dimensional MoSe2. 2g The difference between the two peaks is 47.1 cm. -1 Furthermore, the interlayer vibration peak is relatively large, and a comparison with the literature shows that the number of atomic layers of the grown two-dimensional MoSe2 is one.

[0066] Figure 5The image shows the IV curves of the two-dimensional MoSe2 / GaN photodetector grown in this embodiment under dark and light conditions. The results show that the two-dimensional MoSe2 / GaN photodetector exhibits a significant photoresponse to ultraviolet light. Due to the built-in electric field, photogenerated carriers in the heterojunction are rapidly separated and transferred to the GaN and MoSe2 layers, which increases the photocurrent-to-dark ratio and improves the sensitivity of the photodetector compared to traditional photodetectors.

[0067] Example 2:

[0068] This embodiment provides a method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector, the method comprising:

[0069] Step 1: On a 400 μm thick Si substrate, a 300 nm AlN buffer layer is grown on the substrate using trimethylaluminum (TMAl) as the Al source by metal oxide chemical vapor deposition. Subsequently, a 3 μm GaN layer is grown on the buffer layer using trimethylgallium (TMGa). The growth temperature is set to 1300 °C.

[0070] Step 2: Place the mixed powder of 5 mg MoO3 and 5 mg NaCl and the sample obtained in Step 1 into a quartz boat and send it into the upper temperature zone of a tube furnace. Send 200 mg Se powder into the lower temperature zone of the tube furnace. Pump the gas pressure in the quartz tube to 10-2 Pa, and then pass argon gas into the quartz tube for purging. After purging, reduce the gas pressure to 2000 Pa and control the argon gas flow rate at 80 sccm (argon gas flows from the lower temperature zone to the upper temperature zone). Heat the two temperature zones, with the upper temperature zone reaching 800℃ and the lower temperature zone reaching 400℃, and then hold for growth for 15 minutes.

[0071] Step 3: Spin coat the MoSe2 functional layer of the sample obtained in Step 2 at a speed of 3000 r / min for 30 s, then dry for 50 s. Align the designated area of ​​the mask with the two ends of the MoSe2 functional layer and expose for 30 s. Finally, develop for 45 s. Then, deposit the Ti / Au metal layer on the sample surface by vapor deposition at a rate of 0.2 nm / min.

[0072] The two-dimensional MoSe2 / GaN photodetector prepared in this embodiment is as follows: Figure 1 , 2 As shown, the buffer layer has a thickness of 300 nm, the GaN layer has a thickness of 3 μm, the two-dimensional MoSe2 layer has two layers, and the Ti / Au metal layer has a thickness of 50 nm and 100 nm for Ti and Au, respectively.

[0073] Example 3:

[0074] This embodiment provides a method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector, the method comprising:

[0075] Step 1: On a sapphire substrate with a thickness of 500 μm, a 300 nm AlN buffer layer is grown on the substrate using trimethylaluminum (TMAl) as the Al source by metal oxide chemical vapor deposition. Then, a 3 μm GaN layer is grown on the buffer layer using trimethylgallium (TMGa). The growth temperature is set to 1300 °C.

[0076] Step 2: Place the mixed powder of 5 mg MoO3 and 5 mg NaCl and the sample obtained in Step 1 into a quartz boat and send it into the upper temperature zone of a tube furnace. Send 200 mg Se powder into the lower temperature zone of the tube furnace. Pump the gas pressure in the quartz tube to 10-2 Pa, and then pass argon gas into the quartz tube for purging. After purging, reduce the gas pressure to 3000 Pa and control the argon gas flow rate at 60 sccm (argon gas flows from the lower temperature zone to the upper temperature zone). Heat the two temperature zones, with the upper temperature zone reaching 750℃ and the lower temperature zone reaching 400℃, and then hold for growth for 10 minutes.

[0077] Step 3: Spin coat the MoSe2 functional layer of the sample obtained in Step 2 at a speed of 3000 r / min for 30 s, then dry for 50 s. Align the designated area of ​​the mask with the two ends of the MoSe2 functional layer and expose for 30 s. Finally, develop for 45 s. Then, deposit the Ti / Au metal layer on the sample surface by vapor deposition at a rate of 0.2 nm / min.

[0078] The two-dimensional MoSe2 / GaN photodetector prepared in this embodiment is as follows: Figure 1 , 2 As shown, the buffer layer has a thickness of 300 nm, the GaN layer has a thickness of 3 μm, the two-dimensional MoSe2 layer has one layer, and the Ti / Au metal layer has thicknesses of 50 nm and 100 nm for Ti and Au, respectively.

[0079] Comparative Example 1:

[0080] This comparative example provides a method for fabricating a MoSe2 / GaN heterojunction photodetector using conventional processes and the characterization results. The method includes:

[0081] Step 1: On a 400 μm thick Si substrate, a 200 nm AlN buffer layer is grown on the substrate using trimethylaluminum (TMAl) as the Al source by metal oxide chemical vapor deposition. Subsequently, a 2 μm GaN layer is grown on the buffer layer using trimethylgallium (TMGa). The growth temperature is set to 1300 °C.

[0082] Step 2: Place 5 mg of MoO3 powder and the sample obtained in Step 1 into a quartz boat and place it in the upper temperature zone of a tube furnace. Place 200 mg of Se powder into the lower temperature zone of the tube furnace and evacuate the air pressure in the quartz tube to 10.-2 Pa, then argon gas is introduced into the quartz tube for purging. After purging, the gas pressure is controlled at one atmosphere (1.013 × 10⁻⁶). 5 At Pa), the argon flow rate was controlled at 80 sccm (argon flowed from the lower temperature zone to the upper temperature zone). The two temperature zones were heated to 800℃ in the upper temperature zone and 400℃ in the lower temperature zone. After heating, the temperature was maintained for 10 minutes. After the growth was completed, the atomic layer number and chemical composition were analyzed by Raman spectroscopy.

[0083] Step 3: Spin coat the MoSe2 functional layer of the sample obtained in Step 2 at a speed of 3000 r / min for 30 s, then dry for 50 s. Align the designated area of ​​the mask with the two ends of the MoSe2 functional layer and expose for 30 s. Finally, develop for 45 s. Then, deposit the Ti / Au metal layer on the sample surface by vapor deposition at a rate of 0.2 nm / min.

[0084] The two-dimensional MoSe2 / GaN photodetector prepared in this comparative example is as follows: Figure 1 , 2 As shown, the buffer layer has a thickness of 200 nm, the GaN layer has a thickness of 2 μm, the MoSe2 is a bulk multilayer MoSe2, and the Ti / Au metal layer has thicknesses of 50 nm and 100 nm for Ti and Au, respectively.

[0085] Figure 6 This is an optical microscope image of the MoSe2 / GaN heterojunction grown in this comparative example. The dark area is the MoSe2 grown on GaN, and the light area is the surface of the uncovered GaN layer. It can be seen that MoSe2 was successfully grown on GaN in this embodiment.

[0086] Figure 7 This is the Raman spectrum of the MoSe2 / GaN heterojunction grown in this comparative example, where 238 cm⁻¹... -1 The peak at that point represents the interlayer vibration mode (A) of MoSe2. 1g ), 304cm -1 The peak at that point represents the in-plane vibrational mode (E) of MoSe2. 2g ), 254cm -1 The peak at that point represents the vibrational mode of the Mo-O bond, proving that the grown MoSe2 contains MoO. x Impurities, the peaks of interlayer vibration and in-plane vibration differ by 66 cm. -1 Furthermore, the in-plane vibration peak and the interlayer vibration peak are of similar size, indicating that the grown material is bulk MoSe2, not two-dimensional MoSe2, and of poor quality with many impurities. This is because NaCl was not added during the growth process, resulting in a high precursor melting temperature. Mo and Se sources could not be deposited together, thus preventing growth in a two-dimensional growth mode.

[0087] The above embodiments are preferred embodiments of the present invention, but the scope of protection of the present invention is not limited to the embodiments described. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector, characterized in that, Includes the following steps: Step 1: A buffer layer is grown on the substrate using metal oxide chemical vapor deposition, followed by the growth of a GaN layer on the buffer layer; Step 2: Using MoO3 and Se as precursors, two-dimensional MoSe2 is grown on the GaN layer prepared in Step 1 by chemical vapor deposition; NaCl is also added to the MoO3; the mass ratio of MoO3 to NaCl is 1:0.7 to 1:1; the mass ratio of Se to MoO3 is 40:1 to 48:

1. In step 2, the growth of two-dimensional MoSe2 is carried out under a protective atmosphere; the pressure of the protective atmosphere is 1000-5000 Pa. The MoO3 and the GaN matrix are located in the upper temperature region, where the temperature is 750–800°C; the Se is located in the lower temperature region, where the temperature is 400–450°C. Step 3: Use photolithography combined with vapor deposition to fabricate Ti / Au electrodes at both ends of the MoSe2 functional layer.

2. The method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector according to claim 1, characterized in that, The gas flow rate of the protective atmosphere is 60–80 sccm; in step 2, a vacuum is drawn before the growth of two-dimensional MoSe2, and then a protective gas is introduced for purging; the vacuum degree of the vacuum is 1–10. -2 Pa; The protective gas in the protective atmosphere flow is argon.

3. The method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector according to claim 1, characterized in that, The incubation time for growing two-dimensional MoSe2 is 10-15 minutes.

4. The method for fabricating a two-dimensional MoSe2 / GaN heterojunction photodetector according to claim 1, characterized in that, The temperature of the growth buffer layer in step 1 is 1000-1300℃; the temperature of the GaN layer growth is 1100-1400℃. The photolithography described in step 3 includes spin coating, drying, exposure, and development; the spin coating speed is 2500-3000 r / min, the spin coating time is 25-30 s, the drying time is 40-50 s, the exposure time is 25-30 s, and the development time is 40-45 s. The evaporation rate in step 3 is 0.1–0.2 nm / min.

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