Gallium oxide PN heterojunction solar blind detector and preparation method thereof

Abstract

The invention discloses a gallium oxide PN heterojunction solar blind detector and a preparation method thereof, the gallium oxide PN heterojunction solar blind detector comprises a substrate, a gallium oxide layer, an insulating layer, a P-type layer, a first electrode and a second electrode, the gallium oxide layer is arranged on the substrate, the material of the gallium oxide layer is single crystal or polycrystal epsilon-Ga2O3, and the insulating layer is arranged on the first electrode. The gallium oxide layer is arranged on the substrate, the insulating layer is arranged on the gallium oxide layer and covers part of the gallium oxide layer, the resistivity of the insulating layer is larger than 1010 omega.cm, the P-type layer is arranged on the gallium oxide layer, the first electrode is arranged on the area, not covered by the insulating layer, of the gallium oxide layer, and the second electrode is arranged on the area, not covered by the insulating layer, of the gallium oxide layer. The first electrode is arranged on the gallium oxide layer, the first electrode is in contact with the gallium oxide layer, the second electrode is arranged on the P-type layer, and the second electrode is in contact with the P-type layer. According to the solar blind photoelectric detector based on the epsilon-Ga2O3 heterogeneous PN junction, the insulating layer is inserted into the heterojunction interface, the rectification performance of the detector can be effectively improved, the dark state current of the detector is reduced, and the photoelectric characteristic of the detector is comprehensively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar-blind photodetectors, and in particular to a gallium oxide PN heterojunction solar-blind detector and a preparation method thereof. Background Art

[0002] In recent years, solar-blind (200 - 280 nm) photodetectors (SBPDs) have received increasing attention due to their advantages such as low background noise and high sensitivity, and are widely used in military and civilian fields such as space communication, missile warning, and medical detection. Gallium oxide (Ga 2 O 3 ) as a new type of ultra-wide bandgap semiconductor, has a suitable bandgap width (4.9 - 5.3 eV) and good thermal stability, chemical stability, radiation resistance, and high absorption coefficient, and is an ideal material for preparing solar-blind photodetectors.

[0003] Studies have found that gallium oxide exists in multiple allotropes, including α, β, γ, ε / κ, and δ phases. Among them, β-Ga 2 O 3 (β-phase gallium oxide) is the most stable thermodynamically. Therefore, most solar-blind photodetectors in the prior art are prepared using β-Ga 2 O 3 . Compared with β-Ga 2 O 3 , ε-Ga 2 O 3 (ε-phase gallium oxide) has better substrate compatibility and can be epitaxially grown on a variety of commercial heterosubstrates, which provides great possibilities for the construction of heterojunction detectors based on ε-Ga 2 O 3 . Currently, numerous literature reports that the optoelectronic properties of ε-Ga 2 O 3 are superior to those of epitaxially grown β-Ga 2 O 3 . However, due to its poor tunability of transport properties and the problem of more interface defects after combination with other heterogenous P-type materials, the rectifying performance of its PN heterojunction device is poor and the dark current is also high, which severely limits the application of ε-Ga 2 O 3 in PN heterojunction devices. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is how to reduce the dark current of a heterogenous PN junction device based on ε-Ga 2 O 3 and construct a gallium oxide PN heterojunction solar-blind detector.

[0005] To achieve the above object, the present invention provides a gallium oxide PN heterojunction solar-blind detector, which includes a substrate, a gallium oxide layer, an insulating layer, a P-type layer, a first electrode and a second electrode. The gallium oxide layer is disposed on the substrate, and the material of the gallium oxide layer is single-crystal or polycrystalline ε-Ga 2 O 3 , the insulating layer is disposed on the gallium oxide layer, the insulating layer covers a part of the gallium oxide layer, and the resistivity of the insulating layer is greater than 10 10 Ω·cm. The P-type layer is disposed on the gallium oxide layer, the first electrode is disposed on the region of the gallium oxide layer not covered by the insulating layer, the first electrode is in contact with the gallium oxide layer, the second electrode is disposed on the P-type layer, and the second electrode is in contact with the P-type layer.

[0006] The present invention constructs a solar-blind photodetector device based on an ε-Ga 2 O 3 heterogeneous PN junction. By inserting an insulating layer at the heterojunction interface, the dark current of the device can be effectively reduced, and the optoelectronic performance of the device can be comprehensively improved.

[0007] Further, the material of the insulating layer is selected from one of Ga 2 O 3 , HfO 2 , ZrO 2 , SiO 2 , Si 3 N 4 .

[0008] Further, the thickness of the insulating layer is 50~200 nm.

[0009] Selecting a suitable insulating layer material and designing the thickness of the insulating layer are beneficial to reducing the dark current of the device.

[0010] Further, the carrier concentration of the gallium oxide layer is 10 15 ~10 18 cm -3 .

[0011] Further, the thickness of the gallium oxide layer is 200~1000 nm.

[0012] The gallium oxide layer, as the main light-absorbing layer, is beneficial to improving the optoelectronic performance of the device by selecting a reasonable film thickness and carrier concentration.

[0013] Further, the material of the P-type layer is selected from one of NiO, Cu 2 O, CuAlO 2 . Further, the carrier concentration of the P-type layer is 1018 ~10 20 cm -3 。

[0014] Furthermore, the thickness of the P-type layer is 10~100 nm.

[0015] The main functions of the P-type layer in the device are to provide hole conduction and form a PN junction.

[0016] Furthermore, the material of the substrate is selected from one of single crystal Ga 2 O 3 , sapphire, GaN, and AlN.

[0017] Furthermore, the material of the first electrode is selected from one of Al, W, Mo, and Ti-Au, and the material of the second electrode is selected from one of ITO, Ni-Au, and Pt-Au.

[0018] Through reasonable film layer and interface design, the present invention improves the optoelectronic performance of the device and obtains a gallium oxide PN heterojunction solar-blind detector with high response performance.

[0019] The present invention also provides a preparation method for the above-mentioned gallium oxide PN heterojunction solar-blind detector, comprising the following steps: S1. Deposit ε-Ga 2 O 3 on a clean substrate to obtain a gallium oxide layer; S2. Deposit an insulating material thin film on a partial area of the gallium oxide layer to obtain an insulating layer; S3. Deposit a P-type layer on the insulating layer; S4. Prepare a first electrode in the area of the gallium oxide layer not covered by the insulating layer, and prepare a second electrode on the P-type layer.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention constructs for the first time a solar-blind optoelectronic detection device based on a heterojunction PN junction of ε-Ga 2 O 3 , expanding the application fields of ε-Ga 2 O 3 heterojunction devices.

[0021] (2) By inserting an insulating layer at the interface of the ε-Ga 2 O 3 heterojunction PN junction, the present invention effectively reduces the dark current of the device and comprehensively improves the optoelectronic performance of the device, providing an effective optimization strategy for the preparation and development of gallium oxide heterojunction devices.

[0022] (3)The present invention provides a method for preparing a gallium oxide PN heterojunction solar-blind detector, which has a simple preparation process and great cost advantages. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of a gallium oxide PN heterojunction solar-blind detector in the specific embodiment of the present invention.

[0024] Figure 2 It is a current-voltage curve diagram of the solar-blind detector in Embodiment 1 of the present invention under dark state and illumination.

[0025] Figure 3 It is a current-voltage curve diagram of the solar-blind detector in Embodiment 2 of the present invention under dark state and illumination.

[0026] Figure 4 It is a current-voltage curve diagram of the solar-blind detector in Embodiment 3 of the present invention under dark state and illumination.

[0027] Description of the reference numerals: 1 - Substrate, 2 - Gallium oxide layer, 3 - Insulating layer, 4 - P-type layer, 5 - First electrode, 6 - Second electrode. Specific Embodiments

[0028] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the drawings.

[0029] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0030] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention's specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art.

[0031] The specific embodiments of the present invention provide a gallium oxide PN heterojunction solar-blind detector and a method for preparing the same. The structure of the gallium oxide PN heterojunction solar-blind detector is as Figure 1 shown, including a substrate 1; a gallium oxide layer 2 is provided on the substrate 1, and the material of the gallium oxide layer 2 is single-crystal or polycrystalline ε-Ga 2 O 3; An insulating layer 3 is provided on the gallium oxide layer 2, and the insulating layer 3 covers the surface of a part of the gallium oxide layer 2; a first electrode 5 is provided on the area of the gallium oxide layer 2 not covered by the insulating layer 3, and the first electrode 5 is in contact with the gallium oxide layer 2; a P-type layer 4 is provided on the insulating layer 3; a second electrode 6 is provided on the P-type layer 4, and the second electrode 6 is in contact with the P-type layer 4.

[0032] The above-mentioned solar-blind detector can effectively reduce the dark current of the device and comprehensively improve the optoelectronic performance of the device by inserting an insulating layer 3 at the heterojunction interface. Preferably, the resistivity of the insulating layer 3 is greater than 10 10 Ω·cm, and the material of the insulating layer 3 can be selected from amorphous, polycrystalline or single-crystalline Ga 2 O 3 、HfO 2 ,、ZrO 2 、SiO 2 、Si 3 N 4 etc., with a typical thickness of 50 - 200 nm, preferably 100 - 150 nm.

[0033] In the PN heterojunction solar-blind detector, reasonable film layer and interface design are the key to improving the device performance. In specific embodiments, the material of the substrate 1 can be selected from single-crystalline Ga 2 O 3 、sapphire, GaN, AlN, etc. The gallium oxide layer 2 serves as the main light-absorbing layer, and its carrier concentration range is 10 15 ~10 18 cm -3 , with a typical thickness of 200 - 1000 nm, preferably 400 - 600 nm. The material of the P-type layer 4 can be selected from polycrystalline, amorphous or single-crystalline NiO, Cu 2 O, CuAlO 2 etc., and the carrier concentration range is 10 18 ~10 20 cm -3 , preferably amorphous NiO material; the typical thickness of the P-type layer 4 is 10 - 100 nm, preferably 30 - 50 nm. The material of the first electrode 5 can be selected from Al, W, Mo, Ti-Au, etc., with a typical thickness of 50 - 200 nm, preferably 80 - 150 nm. The material of the second electrode 6 can be selected from ITO, Ni-Au, Pt-Au, etc., with a typical thickness of 50 - 200 nm, preferably 80 - 150 nm.

[0034] The present invention constructs a solar-blind optoelectronic detection device based on an ε-Ga 2 O 3 heterojunction PN junction, expands the application field of ε-Ga 2 O 3 heterojunction devices, and by inserting an insulating layer 3 at the ε-Ga 2O 3 Inserting an insulating layer at the hetero - PN junction interface effectively reduces the dark - state current of the device and comprehensively improves the optoelectronic performance of the device, providing an effective optimization strategy for the preparation and development of gallium oxide heterojunction devices.

[0035] The preparation method of the above - mentioned gallium oxide PN heterojunction solar - blind detector includes the following steps: S1. Deposit ε - Ga 2 O 3 on a clean substrate 1 to obtain a gallium oxide layer 2.

[0036] S2. Deposit an insulating material thin - film on a partial area of the gallium oxide layer 2 to obtain an insulating layer 3.

[0037] S3. Deposit a P - type layer 4 on the insulating layer 3.

[0038] S4. Prepare a first electrode 5 in the area of the gallium oxide layer 3 that is not covered by the insulating layer; prepare a second electrode 6 on the P - type layer 4.

[0039] The following takes specific examples to illustrate the technical solutions and effects of the present invention.

[0040] Example 1

[0041] This example provides a gallium oxide PN heterojunction solar - blind detector, including a sapphire substrate; an ε - Ga 2 O 3 thin - film is provided on the sapphire substrate, the carrier concentration of the thin - film is about 10 17 cm -3 , and the thickness is 1 μm; a Ti - Au electrode with a thickness of 100 nm is provided on a partial area above the ε - Ga 2 O 3 thin - film; an insulating ε - Ga 2 O 3 thin - film is provided on the area above the ε - Ga 2 O 3 thin - film that is not covered by the Ti - Au electrode, and the thickness of the insulating ε - Ga 2 O 3 thin - film is 100 nm; a P - type amorphous NiO thin - film is provided above the insulating ε - Ga 2 O 3 thin - film, and its carrier concentration is controlled at 10 19 cm -3 , and the thickness is 30 nm; a Pt - Au electrode with a thickness of 100 nm is provided above the NiO thin - film.

[0042] The specific manufacturing process of the gallium oxide PN heterojunction solar - blind detector in this example is as follows: 1) Plasma clean the sapphire substrate and blow it dry with nitrogen.

[0043] 2) Deposit ε-Ga 2 O 3 thin film above the sapphire substrate.

[0044] 3) Cover part of the ε-Ga 2 O 3 thin film with a clean blank sapphire substrate for subsequent electrode deposition, and grow an insulating ε-Ga 2 O 3 thin film on the exposed ε-Ga 2 O 3 thin film.

[0045] 4) Use photolithography technology to cover a mask on the surface of the insulating ε-Ga 2 O 3 thin film, and use sputtering technology to grow a NiO thin film on the exposed area of the thin film surface.

[0046] 5) Deposit Ti-Au and Pt-Au electrodes on the surfaces of the ε-Ga 2 O 3 thin film and the NiO thin film respectively.

[0047] Figure 2 Figure is the current-voltage (I-V) curve of the gallium oxide PN heterojunction solar-blind detector prepared in this embodiment in the dark state and under ultraviolet light irradiation at 254 nm.

[0048] Example 2

[0049] This embodiment provides a gallium oxide PN heterojunction solar-blind detector, including a sapphire substrate; an ε-Ga 2 O 3 thin film is provided on the sapphire substrate, and the carrier concentration of the thin film is about 10 17 cm -3 , and the thickness is 0.7 μm; a Ti-Au electrode with a thickness of 100 nm is provided in a partial area above the ε-Ga 2 O 3 thin film; an amorphous SiO 2 O 3 thin film is provided in the area above the ε-Ga 2 O 2 thin film where the Ti-Au electrode is not covered, and the thickness of the SiO 2 thin film is 50 nm; a P-type amorphous NiO thin film with a carrier concentration controlled at 10 19 cm -3 is provided above the SiO 2 thin film, and the thickness is 30 nm; a Pt-Au electrode with a thickness of 100 nm is provided above the NiO thin film.

[0050] The specific manufacturing process of the gallium oxide PN heterojunction solar-blind detector in this embodiment is as follows: 1) Plasma clean the sapphire substrate and dry it with nitrogen.

[0051] 2) Deposit ε-Ga 2 O 3 thin film above the sapphire substrate.

[0052] 3) Cover part of the ε-Ga 2 O 3 thin film with a clean blank sapphire substrate for subsequent electrode deposition. Deposit an amorphous SiO 2 O 3 thin film on the exposed ε-Ga 2 thin film.

[0053] 4) Use photolithography technology to cover a mask on the surface of the amorphous SiO 2 thin film, and use sputtering technology to grow a NiO thin film in the exposed area on the surface of the thin film.

[0054] 5) Deposit Ti-Au and Pt-Au electrodes on the surfaces of the ε-Ga 2 O 3 thin film and the NiO thin film respectively.

[0055] Figure 3 Figure is the current-voltage (I-V) curve of the gallium oxide PN heterojunction solar-blind detector prepared in this embodiment in the dark state and under ultraviolet light irradiation of 254 nm.

[0056] Example 3

[0057] This embodiment provides a gallium oxide PN heterojunction solar-blind detector, including a sapphire substrate; an ε-Ga 2 O 3 thin film is provided on the sapphire substrate, and the carrier concentration of the thin film is about 10 17 cm -3 , and the thickness is 1 μm; an insulating Ga 2 O 3 thin film is provided on the ε-Ga 2 O 3 thin film, and the thickness of the thin film is 0.7 μm; a Ti-Au electrode with a thickness of 100 nm is provided in a partial area above the insulating Ga 2 O 3 thin film; a P-type amorphous NiO thin film is provided in the area above the insulating Ga 2 O 3 thin film where the Ti-Au electrode is not covered, and its carrier concentration is controlled at 10 19 cm -3, with a thickness of 30 nm; a Pt-Au electrode is provided above the NiO thin film, and the thickness of the Pt-Au electrode is 100 nm.

[0058] The specific manufacturing process of the gallium oxide PN heterojunction solar-blind detector in this embodiment is as follows: 1) Plasma clean the sapphire substrate and dry it.

[0059] 2) Deposit ε-Ga 2 O 3 thin film 3) Cover part of the ε-Ga 2 O 3 thin film with a clean blank sapphire substrate for subsequent electrode deposition. Deposit an insulating Ga 2 O 3 thin film on the exposed ε-Ga 2 O 3 thin film.

[0060] 4) Cover part of the insulating Ga 2 O 3 thin film with a clean blank sapphire substrate for subsequent electrode deposition. Use sputtering technology to grow a NiO thin film on the exposed area of the thin film surface.

[0061] 5) Deposit Ti-Au and Pt-Au electrodes on the surfaces of the insulating Ga 2 O 3 thin film and the NiO thin film respectively.

[0062] Figure 4 is the current-voltage (I-V) curve of the gallium oxide PN heterojunction solar-blind detector prepared in this embodiment in the dark state and under ultraviolet light irradiation of 254 nm.

[0063] Comparative Example 1 This embodiment provides a gallium oxide PN heterojunction solar-blind detector, including a sapphire substrate; an ε-Ga 2 O 3 thin film is provided on the sapphire substrate, and the carrier concentration of the thin film is about 10 17 cm -3 , with a thickness of 1 μm; a Ti-Au electrode with a thickness of 100 nm is provided in a partial area above the ε-Ga 2 O 3 thin film; a P-type amorphous NiO thin film with a carrier concentration controlled at 10 2 O 3 thin film is provided in the area above the ε-Ga 19 cm -3, with a thickness of 30 nm; a Pt-Au electrode is provided above the NiO thin film, and the thickness of the Pt-Au electrode is 100 nm.

[0064] The specific manufacturing process of the gallium oxide PN heterojunction solar-blind detector in this embodiment is as follows: 1) Plasma clean the sapphire substrate and dry it with nitrogen.

[0065] 2) Deposit ε-Ga 2 O 3 thin film above the sapphire substrate.

[0066] 3) Cover part of the ε-Ga 2 O 3 thin film with a clean blank sapphire substrate for subsequent electrode deposition, and grow a NiO thin film on the exposed area of the thin film surface using sputtering technology.

[0067] 4) Deposit Ti-Au and Pt-Au electrodes on the surfaces of the ε-Ga 2 O 3 thin film and the NiO thin film respectively.

[0068] Test the current-voltage (I-V) curves of the gallium oxide PN heterojunction solar-blind detector prepared in this comparative example in the dark state and under ultraviolet light irradiation at 254 nm.

[0069] Compare the current-voltage curves of Example 1 and Comparative Example 1 to prove that inserting a suitable insulating layer at the ε-Ga 2 O 3 heterogeneous PN junction interface can effectively reduce the dark current of the device and is beneficial to improving the optoelectronic performance of the device.

[0070] Although the present invention is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A gallium oxide PN heterojunction solar-blind detector, characterized in that: The invention comprises a substrate, a gallium oxide layer, an insulating layer, a P-type layer, a first electrode and a second electrode, wherein the gallium oxide layer is arranged on the substrate, the material of the gallium oxide layer is single crystal or polycrystalline ε-Ga2O3, the insulating layer is arranged on the gallium oxide layer, the insulating layer covers a part of the gallium oxide layer, and the resistivity of the insulating layer is greater than 10 10 Ω·cm, the P-type layer is arranged on the gallium oxide layer, the first electrode is arranged on a region of the gallium oxide layer not covered by the insulating layer, the first electrode is in contact with the gallium oxide layer, and the second electrode is arranged on the P-type layer, the second electrode is in contact with the P-type layer.

2. The gallium oxide PN heterojunction solar-blind detector according to claim 1, characterized in that: The material of the insulating layer is selected from one of Ga2O3, HfO2, ZrO2, SiO2, and Si3N4.

3. The gallium oxide PN heterojunction solar-blind detector according to claim 2, characterized in that: The thickness of the insulating layer is 50-200 nm.

4. The gallium oxide PN heterojunction solar-blind detector according to claim 1, characterized in that: The carrier concentration of the gallium oxide layer is 10 15 ~10 18 cm -3 .

5. The gallium oxide PN heterojunction solar-blind detector according to claim 4, characterized in that: The thickness of the gallium oxide layer is 200-1000 nm.

6. The gallium oxide PN heterojunction solar-blind detector according to claim 1, characterized in that: The material of the P-type layer is selected from one of NiO, Cu2O and CuAlO2.

7. The gallium oxide PN heterojunction solar-blind detector according to claim 6, characterized in that: The carrier concentration of the P-type layer is 10 18 ~10 20 cm -3 .

8. The gallium oxide PN heterojunction solar-blind detector according to claim 7, characterized in that: The thickness of the P-type layer is 10-100 nm.

9. The gallium oxide PN heterojunction solar-blind detector according to claim 1, characterized in that: The material of the substrate is selected from one of single crystal Ga2O3, sapphire, GaN and AlN.

10. The gallium oxide PN heterojunction solar-blind detector according to claim 1, characterized in that: The material of the first electrode is selected from one of Al, W, Mo, and Ti-Au, and the material of the second electrode is selected from one of ITO, Ni-Au, and Pt-Au.

11. A method for preparing a gallium oxide PN heterojunction solar-blind detector according to any one of claims 1 to 10, characterized in that: The following steps are involved: S1, depositing ε-Ga2O3 on a clean substrate to obtain a gallium oxide layer; S2, depositing an insulating material film on a partial area of ​​the gallium oxide layer to obtain an insulating layer; S3, depositing a P-type layer on the insulating layer; S4. Prepare a first electrode on the area of ​​the gallium oxide layer not covered by the insulating layer, and prepare a second electrode on the P-type layer.

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