Ga2O3 / Bi2Te3 transverse heterojunction photoelectric detector and preparation method thereof

Abstract

The invention provides a Ga2O3 / Bi2Te3 transverse heterojunction photoelectric detector and a preparation method thereof, and the method comprises the steps: S1, obtaining a Ga2O3 substrate, and carrying out the patterning, photoetching and etching of the Ga2O3 substrate, and obtaining a Ga2O3 active region; s2, depositing a SiO2 protective layer on the Ga2O3 active region, and patterning on the SiO2 protective layer to obtain an ion implantation region exposing the surface of the Ga2O3 active region; s3, single-side Si ion implantation is carried out on the Ga2O3 active region in the ion implantation region, and ion implantation activation annealing is carried out; s4, depositing a first metal electrode on the ion implantation region by using an EBV and stripping technology, and performing ohmic annealing on the first metal electrode; and S5, depositing a Bi2Te3 thin film on the other side, opposite to the ion implantation region, of the Ga2O3 active region by using a magnetron sputtering and stripping technology, and depositing a second metal electrode on Bi2Te3 by using an EBV and stripping technology to obtain the pn transverse heterojunction photoelectric detector with excellent performances such as high light responsivity, high light detection degree, low dark current and high response speed.

Description

Technical Field

[0001] The present invention relates to the technical field of wide bandgap compound semiconductors and the field of photoelectric detection, and in particular to a Ga2O3 / Bi2Te3 lateral heterojunction photoelectric detector and a preparation method thereof. Background Art

[0002] A photodetector is a specialized device that converts light signals into electrical signals. Its core principle is to utilize the intrinsic photoelectric effect (i.e., the photoconductivity and photovoltaic effects) to convert photon energy into a detectable current or voltage. Currently, mainstream photodetectors on the market are typically made of semiconductor materials such as silicon (Si), germanium (Ge), and indium gallium arsenide (InGaAs). Their effective spectral detection range is primarily concentrated in the visible and near-infrared regions. With the advancement of technology, the demand for ultraviolet (UV) photodetectors is increasing, and mainstream photodetectors are no longer able to meet detection needs. Due to atmospheric scattering, UV light with a wavelength between 200-280nm is virtually absent in the near-Earth atmosphere, hence the term "solar-blind UV light." Solar-blind UV detectors have important applications in civilian and military fields, such as flame detection, arc detection, and missile wake detection. As a new wide-bandgap semiconductor material, gallium oxide (Ga2O3) boasts an extremely large bandgap (approximately 4.9 eV), high physical and chemical stability, the ability to operate in high-voltage environments, and significant absorption of solar-blind UV light, making it an ideal material for solar-blind UV detectors.

[0003] However, Ga2O3 UV detectors also suffer from low responsivity, slow response speed, and high dark current. Current research focuses on addressing these issues by designing different device structures and optimizing process flows. After years of research, researchers have developed several types of Ga2O3 photodetectors, including photoconductive, Schottky, and pn heterojunction. The pn heterojunction Ga2O3 photodetector, which utilizes a built-in electric field formed by contacting semiconductors of different conductivity types to promote the separation of photogenerated carriers, offers high sensitivity, fast response, and high quantum efficiency, making it the highest-performing of these detector structures.

[0004] Most of the pn heterojunction Ga2O3 photodetectors reported so far mainly use sol-gel, chemical vapor deposition (CVD), electron beam evaporation (EBV) and other methods to prepare p-type materials. However, these methods all have significant limitations: for example, the sol-gel method has a long process cycle, cumbersome drying and heat treatment steps after gelation, high precursor raw material costs, and very complex process control. Slight fluctuations in reaction conditions can easily lead to performance differences between devices in different batches, affecting repeatability and making large-scale market preparation difficult. The CVD method has a high reaction temperature, and the high-temperature process can easily cause damage to the substrate or material structure, and the deposition rate is very low. The gas source involved in the deposition reaction and the residual gas after the reaction are both toxic, posing certain safety risks. The thin film deposited by the EBV method has weak adhesion to the substrate and is easily detached in subsequent process steps. In addition, the high-temperature process can easily cause the low-melting-point components in the multi-component material to volatilize, resulting in an imbalance in the film composition ratio and affecting its conductivity.

[0005] In addition, most current photodetectors use a vertical heterojunction structure, and the preparation process of the vertical heterojunction structure is complex. It requires precise control of the vertical stacking of different materials, especially the alignment of atomically thick materials (such as two-dimensional materials), which makes the process more difficult. In addition, the vertically stacked different materials produce interface defects due to differences in lattice constants, which increases carrier recombination centers and causes a large dark current in the device. In addition, since photogenerated carriers need to be transmitted across multiple layers of interfaces, the transmission path is long and the recombination probability is high. Therefore, the photoresponsivity of most pn vertical heterojunction devices in self-powered mode is low, all less than 1mA / W, and the response time (rise time and fall time) is limited, all in the order of seconds. These low photoresponsivity and slow response time greatly limit the application of the device.

[0006] Therefore, it is necessary to use a method that is simple to operate, high in efficiency, and low in cost to prepare a pn heterojunction Ga2O3 photodetector with high photoresponsivity, fast response time, and low dark current. Summary of the Invention

[0007] The purpose of the present invention is to provide a Ga2O3 / Bi2Te3 lateral heterojunction photodetector and a preparation method thereof, wherein a Bi2Te3 thin film is deposited on the Ga2O3 surface by magnetron sputtering to form a lateral heterojunction interface, thereby obtaining a pn lateral heterojunction photodetector with excellent performance such as high photoresponsivity, high photodetectability, low dark current and fast response speed.

[0008] To achieve the above objectives, the present technical solution provides a method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector, comprising the following steps:

[0009] S1: Obtain a Ga2O3 substrate, perform patterning, photolithography, and etching on the Ga2O3 substrate to obtain a Ga2O3 active region;

[0010] S2: depositing a SiO2 protective layer on the Ga2O3 active area and patterning the SiO2 protective layer to obtain an ion implantation area exposing the surface of the Ga2O3 active area;

[0011] S3: Single-side Si ion implantation is performed on the Ga2O3 active area in the ion implantation area and ion implantation activation annealing is performed;

[0012] S4: depositing a first metal electrode on the ion implantation area using EBV and lift-off technology, and performing ohmic annealing on the first metal electrode;

[0013] S5: depositing a Bi2Te3 thin film on the other side of the Ga2O3 active region relative to the ion implantation region using magnetron sputtering and lift-off technology, and depositing a second metal electrode on the Bi2Te3 using EBV and lift-off technology.

[0014] In a second aspect, the present technical solution provides a Ga2O3 / Bi2Te3 lateral heterojunction photodetector, comprising:

[0015] A Ga2O3 substrate is formed with at least one Ga2O3 channel, and Si ions are implanted on one side of the ion implantation region of the Ga2O3 channel;

[0016] a first metal electrode deposited on the ion implanted region of the Ga2O3 channel;

[0017] A Bi2Te3 film is formed on the opposite side of the ion-implanted region of the Ga2O3 channel by magnetron sputtering;

[0018] A second metal electrode is deposited on the Bi2Te3 thin film.

[0019] Compared with the existing technology, this technical solution has the following characteristics and beneficial effects:

[0020] This approach first patterns a Ga2O3 substrate, using photolithography and etching to create Ga2O3 active regions of varying lengths and widths. Si ion implantation and post-implantation activation annealing are then performed on one side of the Ga2O3 active region. A first metal electrode is then photolithographed and deposited on the Ga2O3 in the ion-implanted region using EBV and lift-off techniques. This first metal electrode is then ohmically annealed to form an ohmic contact with the Ga2O3. A Bi2Te3 region is then photolithographed and a Bi2Te3 thin film is deposited on the other side of the Ga2O3 active region using magnetron sputtering and lift-off techniques. A second metal electrode is then deposited on the Bi2Te3 using the same method, resulting in a Ga2O3 / Bi2Te3 heterojunction photodetector. This simple fabrication process utilizes low-temperature magnetron sputtering to produce a Bi2Te3 thin film with high adhesion, high uniformity, and low defects. This generates a strong built-in electric field at the interface of the lateral heterojunction, shortening the transport path of photogenerated carriers and significantly improving the response speed and photoresponsivity of the photodetector. Moreover, the lateral heterojunction is easy to process by photolithography, supports high-density photodetector arrays, has stronger tolerance to mechanical bending, and is suitable for imaging sensing systems and various flexible electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector after depositing the first metal electrode.

[0022] Figure 2 This is a structural diagram of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector after depositing Bi2Te3 thin film.

[0023] Figure 3 This is a structural diagram of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector after depositing the second metal electrode. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0025] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0026] Example 1

[0027] This solution provides a method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector, comprising the following steps:

[0028] S1: Obtain a Ga2O3 substrate, perform patterning, photolithography, and etching on the Ga2O3 substrate to obtain a Ga2O3 active region;

[0029] S2: depositing a SiO2 protective layer on the Ga2O3 active area and patterning the SiO2 protective layer to obtain an ion implantation area exposing the surface of the Ga2O3 active area;

[0030] S3: Single-side Si ion implantation is performed on the Ga2O3 active area in the ion implantation area and ion implantation activation annealing is performed;

[0031] S4: depositing a first metal electrode on the ion implantation area using EBV and lift-off technology, and performing ohmic annealing on the first metal electrode;

[0032] S5: depositing a Bi2Te3 thin film on the other side of the Ga2O3 active region relative to the ion implantation region using magnetron sputtering and lift-off technology, and depositing a second metal electrode on the Bi2Te3 using EBV and lift-off technology.

[0033] This scheme adopts lateral heterojunction structure design and asymmetric doping technology combined with low-temperature magnetron sputtering process to prepare a Ga2O3 / Bi2Te3 lateral heterojunction photodetector with Bi2Te3 as the p-type material and Ga2O3 as the n-type material. The Ga2O3 / Bi2Te3 lateral heterojunction photodetector generates a strong built-in electric field at the interface, shortening the transmission path of photogenerated carriers and significantly improving the response speed and photosensitivity of the photodetector. In addition, the lateral heterojunction is easy to process by photolithography, supports high-density photodetector arrays, and has stronger tolerance to mechanical bending, making it suitable for imaging sensing systems and various flexible electronic devices.

[0034] Regarding step S1:

[0035] A high-purity Ga2O3 single crystal is obtained and cleaned and dried to serve as a Ga2O3 substrate. The Ga2O3 substrate is patterned, photolithographically processed, and etched to obtain Ga2O3 active regions of different lengths and widths.

[0036] In some embodiments, the Ga2O3 single crystal is ultrasonically cleaned with acetone, isopropanol, and deionized water for 5 minutes respectively, and then dried with a nitrogen gun to obtain a Ga2O3 substrate.

[0037] Furthermore, after cleaning with acetone and isopropyl alcohol, the substrate was cleaned with piranha solution (concentrated H2SO4:H2O2=3:1) for 30 minutes to remove dangling bonds, surface states and stubborn contamination on the substrate surface.

[0038] In some embodiments, a photoresist is laid on a Ga2O3 substrate and a pre-designed pattern is transferred to the photoresist using photolithography technology. Unnecessary areas are then removed through an etching process to form a recessed Ga2O3 active region on the Ga2O3 substrate. When stimulated by external energy (such as light, electric field, etc.), the Ga2O3 material in the Ga2O3 active region can generate electron-hole pairs, and the Ga2O3 active region provides a channel for carriers to enable the generated carriers to move in a directed manner therein, thereby converting the optical signal into an electrical signal for detection.

[0039] In some embodiments, the etching thickness of the Ga2O3 active region is 400-450 nm. Within this etching thickness range, the carrier concentration and mobility in the Ga2O3 active region can be well controlled. Preferably, the etching thickness of the Ga2O3 active region is 450 nm.

[0040] In some embodiments, the Ga2O3 substrate is etched using inductively coupled plasma etching to obtain a Ga2O3 active region.

[0041] Regarding step S2:

[0042] In some embodiments, a SiO2 protective layer is deposited on the Ga2O3 active area using PECVD technology. The SiO2 protective layer is used to protect the Ga2O3 surface from the impact of subsequent ion implantation, and to reduce direct damage to the Ga2O3 lattice by ions by buffering the energy of the implanted ions.

[0043] In some embodiments, a photoresist is covered on the SiO2 protective layer, and the photoresist is exposed and developed to form a specific pattern. The SiO2 portion not protected by the photoresist is removed using an etching process, thereby forming openings identical to the photoresist pattern on the SiO2 protective layer. These openings correspond to areas where ion implantation is required, so that ions can only be implanted into designated Ga2O3 active area portions, thereby achieving precise doping control.

[0044] In some embodiments, the thickness of the SiO2 protective layer is 40 to 60 nm. This provides a sufficient physical barrier to block direct impact of high-energy ions, impurities, and mechanical stress on the Ga2O3 surface, and facilitates subsequent stripping. Preferably, the thickness of the SiO2 protective layer is 50 nm.

[0045] In some embodiments, the ion implantation region is located at a side of the Ga 2 O 3 active region to facilitate formation of an ohmic contact between the Ga 2 O 3 and the first metal electrode.

[0046] In some embodiments, the ion implantation region exposes the surface of the Ga 2 O 3 active region so that subsequent Si ions can be implanted from the ion implantation region into the Ga 2 O 3 active region.

[0047] Regarding step S3:

[0048] Ion implantation is a technique that introduces specific ions into semiconductor materials to modify their electrical properties. In this approach, Si ions bombard the Ga2O3 active region. These ions penetrate the surface of the Ga2O3 material and enter the crystal lattice, remaining at a certain depth to achieve implantation. After Si ions are injected into the Ga2O3 active region, the Si atoms replace some atoms in the Ga2O3 lattice. Because the number of outer-shell electrons in the Si atoms differs from that of some Ga2O3 atoms, additional electrons are introduced into the Ga2O3 material, increasing the electron concentration in the material and imparting n-type conductivity to the Ga2O3 active region, thereby modifying its electrical properties, such as improving conductivity.

[0049] In some embodiments, Si ions are implanted on one side of the Ga2O3 active region in the ion implantation area, and the SiO2 layer in the non-ion implantation area can be used as a mask for the ion implantation process.

[0050] During the ion implantation process, the energy of the ion implantation can be precisely controlled so that the Si ions have enough energy to penetrate the SiO2 layer (if any residue) and reach a certain depth inside the Ga2O3. At the same time, it is necessary to avoid the ion energy being too high, which may cause the implantation depth to be too deep or cause excessive damage to the Ga2O3, and to avoid the energy being too low, which may cause the ions to stay in the SiO2 layer. In some embodiments, Si ions of different energies are simultaneously implanted obliquely in the ion implantation area to perform single-sided Si ion implantation on the Ga2O3 active area. Specifically, the ion implantation dose is 50keV / 5×10 14 cm -2 、30keV / 5×10 13 cm -2 and 10keV / 3×10 14 cm -2 , and the injection angle is 7°.

[0051] It should be noted that this scheme adopts multi-energy tilted ion implantation technology, with 50keV / 5×10 14 cm -2 、30keV / 5×10 13 cm -2 and 10keV / 3×10 14 cm -2 The dose combination is combined with the 7° incident angle to implement Si ion implantation, forming a carrier concentration gradient spanning 3 orders of magnitude. + / n-type graded doping layer, where the energy is lower (10keV) and the dose is relatively high (3×10 14 / cm 2 ) is shallow, which can increase the carrier concentration near the surface; medium energy (30keV) and low dose (5×10 13 / cm 2 ) ion implantation is slightly deeper; high energy (50keV) and higher dose (5×10 14 / cm 2 ) is the deepest. The carrier concentration changes at different depths create n + / n-type gradient doping layer, expands the width of the space charge region, enhances the ultraviolet light absorption efficiency, and improves the performance of the photodetector.

[0052] In some embodiments, the Ga2O3 active region is subjected to ion implantation activation annealing using rapid annealing (RTP), and the rapid annealing conditions are: a heating rate of 20°C / s, and a temperature maintained at 1000°C for 3 minutes in an N2 atmosphere.

[0053] It should be noted that after the ion implantation is completed, SiO2 is stripped off to facilitate the subsequent deposition of the first metal electrode on the surface of the Ga2O3 active area.

[0054] Regarding step S4:

[0055] After ion implantation, photoresist is evenly coated on the surface of the Ga2O3 active area in the ion implantation area. Photolithography, exposure and development are performed to expose the ion implantation area corresponding to the first metal electrode pattern. Electron beam evaporation technology is used to deposit the first metal electrode in the ion implantation area and remove excess photoresist.

[0056] In some embodiments, the first metal electrode is Ti / Al / Ni and Au deposited from bottom to top, and Ti is in direct contact with the Ga2O3 active area to enhance the bonding force between the entire first metal electrode and the Ga2O3 substrate. At the same time, Ti can form a good ohmic contact with Ga2O3, reduce the contact resistance, facilitate the smooth transmission of carriers between the metal and the semiconductor, and improve the electrical performance of the device; Al is deposited on Ti, which can serve as the main conductive layer, providing a low-resistance transmission path for carriers, effectively reducing the resistance of the electrode and improving the current transmission efficiency; the main function of Ni is to act as a barrier layer, which can prevent Al from diffusing into the Ti layer or the Ga2O3 active area, and also prevent the elements in Ga2O3 from diffusing into the metal electrode, avoiding the influence of the interface characteristics and device performance of the metal and semiconductor due to the diffusion of elements; Au has extremely high conductivity and chemical stability. Depositing Au on the top layer of the first metal electrode can, on the one hand, further reduce the resistance of the electrode and improve the conductive performance of the electrode; on the other hand, Au has good chemical stability, can protect the underlying metal from oxidation and corrosion, and is also beneficial to subsequent metal bonding and other process operations, and is convenient for connection with external circuits.

[0057] In some embodiments, the thickness of Ti is 25-35 nm, the thickness of Al is 100-130 nm, the thickness of Ni is 40-60 nm, and the thickness of Au is 40-60 nm. Preferably, the thickness of Ti is 30 nm, the thickness of Al is 120 nm, the thickness of Ni is 50 nm, and the thickness of Au is 50 nm.

[0058] In some embodiments, the first metal electrode is subjected to ohmic annealing by rapid annealing (RTP), and the conditions of the rapid annealing are: a heating rate of 20° C. / s, and a temperature maintained at 490° C. for 3 minutes in an N 2 atmosphere.

[0059] like Figure 1 As shown, Figure 1 It is a structural diagram of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector after depositing the first metal electrode in step S4.

[0060] Regarding step S5:

[0061] Low-temperature magnetron sputtering is used to deposit a Bi2Te3 thin film on the other side of the Ga2O3 active area relative to the ion implantation area. The low deposition temperature of magnetron sputtering avoids the damage to the material properties caused by high-temperature processes. It is suitable for flexible substrates. The deposition rate reaches 7.5nm / min, and the density and uniformity of the sputtered Bi2Te3 film are very high.

[0062] Specifically, the Bi2Te3 film is deposited on the area of ​​the Ga2O3 active area that is not covered by the SiO2 protective layer and is exposed after patterning. Magnetron sputtering is used to deposit the Bi2Te3 film on this exposed area, and then the excess photoresist and the Bi2Te3 film on the photoresist are removed by stripping technology, leaving the Bi2Te3 film at a specific position on the other side of the ion implantation area of ​​the Ga2O3 active area, so as to subsequently construct a lateral heterojunction structure and play its role in the photodetector.

[0063] In some embodiments, the DC power of magnetron sputtering is 7-9 W, the temperature is 75-85° C., and the sputtering rate is 7-8 nm / min; preferably, the DC power of magnetron sputtering is 8 W, the temperature is 80° C., and the sputtering rate is 7.5 nm / min.

[0064] In some embodiments, the Bi2Te3 film has a thickness of 80 to 120 nm. Preferably, the Bi2Te3 film has a thickness of 100 nm.

[0065] In some embodiments, the gas for magnetron sputtering is pure argon, the gas flow rate is 20-40 Sccm, and the pressure in the reaction chamber is controlled at 0.3-0.6 Pa; preferably, the gas for magnetron sputtering is pure argon, the gas flow rate is 30 Sccm, and the pressure in the reaction chamber is controlled at 0.5 Pa.

[0066] Figure 2 This is the structural diagram of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector after depositing the Bi2Te3 thin film. It can be seen that the Bi2Te3 thin film and the first metal electrode are located on opposite sides of the Ga2O3.

[0067] In some embodiments, photoresist is uniformly coated on the surface of the Bi2Te3 film, and the area corresponding to the second metal electrode pattern is exposed through photolithography, exposure, and development. The second metal electrode is deposited in the ion implantation area using electron beam evaporation technology and excess photoresist is removed.

[0068] In some embodiments, the second metal electrode is aluminum. This solution proposes, for the first time, an innovative strategy for constructing an ohmic contact between an aluminum electrode and the topological insulator Bi2Te3, breaking through the material selection limitations of traditional metal electrode systems. By leveraging the topologically protected Dirac cone metallic state on the Bi2Te3 surface, the aluminum electrode directly couples with high-mobility surface carriers, forming a novel ohmic contact mechanism dominated by interface state tunneling. This design abandons the traditional bandgap control pathway that relies on heavy doping of the bulk material, significantly reducing the contact barrier through the surface state-metal synergistic effect. It also maintains compatibility with low-temperature processing conditions and avoids the risk of thermal degradation. This interface engineering strategy provides a new paradigm for low-power electrode design and large-scale integration of topological insulator-based devices.

[0069] Figure 3 This is the structural diagram of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector after the deposition of the second metal electrode. It can be seen that the Bi2Te3 film and the first metal electrode are located on opposite sides of the Ga2O3.

[0070] In some embodiments, the thickness of the second metal electrode is 80-120 nm. Preferably, the thickness of the second metal electrode is 100 nm.

[0071] It is important to emphasize again that a Bi2Te3 thin film is integrated via low-temperature magnetron sputtering on the opposite side of the ion-implanted region of the Ga2O3 active region, creating a strong built-in electric field at the heterojunction interface and subsequently constructing a Ga2O3 / Bi2Te3 lateral heterojunction. This lateral heterojunction structure generates a strong built-in electric field at the interface, shortening the transmission path of photogenerated carriers and significantly improving the response speed and photoresponsivity of the photodetector. This solution significantly expands the width of the space charge region through the synergistic effect of the unilateral gradient doping and the asymmetric heterojunction, thereby improving the ultraviolet light absorption efficiency. The tilted injection angle design effectively reduces the lattice damage introduced by the ion implantation process. Combined with the inhibitory effect of unilateral doping on interface defects, the device's dark current level is significantly lower than that of traditional symmetrical structure photodetectors.

[0072] Example 2:

[0073] like Figure 3 As shown, this solution provides a Ga2O3 / Bi2Te3 lateral heterojunction photodetector prepared according to the preparation method of the Ga2O3 / Bi2Te3 lateral heterojunction photodetector of Example 1, comprising:

[0074] A Ga2O3 substrate is formed with at least one Ga2O3 channel, and Si ions are implanted on one side of the ion implantation region of the Ga2O3 channel;

[0075] a first metal electrode deposited on the ion implanted region of the Ga2O3 channel;

[0076] A Bi2Te3 film is formed on the opposite side of the ion-implanted region of the Ga2O3 channel by magnetron sputtering;

[0077] A second metal electrode is deposited on the Bi2Te3 thin film.

[0078] The Ga2O3 / Bi2Te3 lateral heterojunction photoelectric detector introduced in the second embodiment is the same as that in the first embodiment and is not described in detail here.

[0079] It should be noted that the Ga2O3 / Bi2Te3 lateral heterojunction photodetector prepared by this scheme has a high-quality Bi2Te3 / Ga2O3 heterojunction interface with low defect density. The rectification ratio of the Bi2Te3 / Ga2O3 heterojunction interface reaches 10 to the fourth power, and the strong built-in electric field generated by the band structure of the lateral heterojunction interface effectively promotes the separation and transport process of photogenerated carriers. Due to the lateral heterojunction structure, the photogenerated carriers flow in the planar direction, the migration path is short, and the recombination probability is low, thereby greatly improving the response speed and light responsivity of the photodetector. Compared with the vertical heterojunction structure, the lateral heterojunction material has a stronger tolerance to mechanical bending, the material is not easy to peel off directly, and is suitable for large-scale array preparation. The present invention has important application potential and value in the field of solar-blind ultraviolet photodetection.

[0080] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The above embodiments merely illustrate several embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector, characterized in that: The following steps are involved: S1: Obtain a Ga2O3 substrate, perform patterning, photolithography, and etching on the Ga2O3 substrate to obtain a Ga2O3 active region; S2: depositing a SiO2 protective layer on the Ga2O3 active area and patterning the SiO2 protective layer to obtain an ion implantation area exposing the surface of the Ga2O3 active area; S3: Single-side Si ion implantation is performed on the Ga2O3 active area in the ion implantation area and ion implantation activation annealing is performed; S4: depositing a first metal electrode on the ion implantation area using EBV and lift-off technology, and performing ohmic annealing on the first metal electrode; S5: depositing a Bi2Te3 thin film on the other side of the Ga2O3 active region relative to the ion implantation region using magnetron sputtering and lift-off technology, and depositing a second metal electrode on the Bi2Te3 using EBV and lift-off technology.

2. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: The SiO2 protective layer was deposited on the Ga2O3 active area using PECVD technology.

3. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: Si ions of different energies are simultaneously and obliquely implanted into the Ga2O3 active region in the ion implantation area to perform single-side Si ion implantation.

4. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 3, characterized in that: The ion implantation dose is 50keV / 5×10 14 cm -2 、30keV / 5×10 13 cm -2 and 10keV / 3×10 14 cm -2 , and the injection angle is 7°.

5. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: The first metal electrode is Ti / Al / Ni and Au deposited from bottom to top.

6. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: The DC power of magnetron sputtering is 7-9 W, the temperature is 75-85° C., and the sputtering rate is 7-8 nm / min.

7. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: The gas used for magnetron sputtering is pure argon, the gas flow rate is 20-40 Sccm, and the pressure in the reaction chamber is controlled at 0.3-0.6 Pa.

8. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: The thickness of Bi2Te3 film is 80~120nm.

9. The method for preparing a Ga2O3 / Bi2Te3 lateral heterojunction photodetector according to claim 1, characterized in that: The second metal electrode is Al.

10. A Ga2O3 / Bi2Te3 lateral heterojunction photodetector, characterized in that: include: A Ga2O3 substrate is formed with at least one Ga2O3 channel, and Si ions are implanted on one side of the ion implantation region of the Ga2O3 channel; a first metal electrode deposited on the ion implanted region of the Ga2O3 channel; A Bi2Te3 film is formed on the opposite side of the ion-implanted region of the Ga2O3 channel by magnetron sputtering; A second metal electrode is deposited on the Bi2Te3 thin film.

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