A gallium oxide / magnesium nickel oxygen heterojunction photodetector and a preparation method thereof

Abstract

The application discloses a gallium oxide / magnesium nickel oxide heterojunction photoelectric detector, which comprises an aluminum oxide substrate, a gallium oxide epitaxial layer deposited on the aluminum oxide substrate, a magnesium nickel oxide film layer deposited on the gallium oxide epitaxial layer, a first electrode forming ohmic contact with the gallium oxide epitaxial layer, and a second electrode forming ohmic contact with the magnesium nickel oxide film layer. The application further discloses a preparation method of the gallium oxide / magnesium nickel oxide heterojunction photoelectric detector, wherein the gallium oxide epitaxial layer is prepared by a metal organic chemical vapor deposition method, and the magnesium nickel oxide film layer is prepared by a magnetron sputtering technology. The gallium oxide / magnesium nickel oxide heterojunction photoelectric detector disclosed by the application has a simple preparation process, can realize self-powered response under zero-voltage bias and photoconductive response under bias mode, and is suitable for high-sensitivity and low-power-consumption solar blind ultraviolet photoelectric detection application.

Description

Technical Field

[0001] This invention relates to the field of semiconductor optoelectronic devices, specifically to a gallium oxide / magnesium nickel oxide heterojunction photodetector and its fabrication method. Background Technology

[0002] Photodetectors are semiconductor devices that convert optical signals into electrical signals, and their core working principle is based on the photoelectric effect. Gallium oxide (GaO), as a typical representative of ultra-wide bandgap semiconductors, has a bandgap as high as 4.9 eV, directly corresponding to the solar-blind ultraviolet band (200-280 nm). Therefore, GaO is an ideal material for fabricating solar-blind ultraviolet photodetectors. Traditional GaO photoconductive detectors mostly adopt a metal-semiconductor-metal structure. Although the fabrication process is simple, it usually requires the application of an external bias voltage. The large dark current and the persistent photoconductive effect result in a slow response speed, making it difficult to meet the requirements of low power consumption and high response speed.

[0003] Constructing heterojunctions is a crucial approach to achieving zero-bias self-powered operation and suppressing dark current. By utilizing a built-in electric field to spontaneously separate photogenerated electron-hole pairs, it can significantly improve response speed and sensitivity. However, the fabrication of high-quality p-type gallium oxide remains a challenge. It has been discovered that introducing magnesium into NiO to form magnesium nickel oxide (MgNiO) can effectively widen the bandgap, allowing the absorption edge to enter the solar-blind ultraviolet region while maintaining p-type conductivity. This results in a heterostructure with better bandgap matching and stronger light absorption. However, research on constructing heterojunction solar-blind ultraviolet detectors combining gallium oxide and MgNiO is still insufficient, and device schemes that simultaneously achieve zero-bias self-powered operation and high-sensitivity photoconductivity under bias are not yet mature.

[0004] Therefore, there is an urgent need to develop a solar-blind ultraviolet heterojunction photodetector that is simple to fabricate, can achieve zero-volt self-powered and bias-voltage multi-mode detection, and has high sensitivity and low power consumption characteristics to meet practical application requirements. Summary of the Invention

[0005] This invention provides a gallium oxide / magnesium nickel oxide heterojunction photodetector and its fabrication method, aiming to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned technical objectives, this invention proposes a gallium oxide / magnesium nickel oxide heterojunction photodetector, comprising: an aluminum oxide substrate; a gallium oxide epitaxial layer deposited on the aluminum oxide substrate; a magnesium nickel oxide thin film layer deposited on the gallium oxide epitaxial layer; a first electrode forming an ohmic contact with the gallium oxide epitaxial layer; and a second electrode forming an ohmic contact with the magnesium nickel oxide thin film layer.

[0007] Furthermore, the gallium oxide epitaxial layer is an n-type semiconductor with a film thickness of 100 nm to 2 μm, preferably 150 nm to 1 μm.

[0008] Furthermore, the magnesium nickel oxide thin film layer is a p-type semiconductor with a film thickness of 50 nm to 200 nm, preferably 100 nm to 150 nm.

[0009] Furthermore, the first electrode that forms an ohmic contact with the gallium oxide epitaxial layer is one or more of copper, silver, titanium, nickel, aluminum, indium, and gold, preferably a combination of titanium and gold.

[0010] Furthermore, the second electrode that forms an ohmic contact with the magnesium-nickel-oxygen thin film layer is one or more of copper, silver, titanium, nickel, aluminum, indium, and gold, preferably a nickel-gold combination.

[0011] The present invention also proposes a method for fabricating a gallium oxide / magnesium nickel oxide heterojunction photodetector, comprising the following steps: fabricating a gallium oxide epitaxial layer on an aluminum oxide substrate, depositing a magnesium nickel oxide thin film layer on the gallium oxide epitaxial layer to form a heterojunction between the gallium oxide epitaxial layer and the magnesium nickel oxide thin film layer, and fabricating a first electrode and a second electrode with ohmic contact on the gallium oxide epitaxial layer and the magnesium nickel oxide thin film layer, respectively.

[0012] Furthermore, the gallium oxide epitaxial layer is prepared on an alumina substrate by metal-organic chemical vapor deposition, wherein the gallium source is triethylgallium or trimethylgallium, preferably triethylgallium; the oxygen source is oxygen or ultrapure water, preferably oxygen; and the carrier gas is nitrogen or argon, preferably nitrogen.

[0013] Furthermore, the magnesium-nickel-oxygen thin film layer is prepared by magnetron sputtering technology, with the target material being an alloy solid solution ceramic of magnesium oxide and nickel oxide, wherein the molar percentage of magnesium oxide is 10%~45%, preferably 20%~35%.

[0014] Furthermore, both the first and second electrodes are prepared using electron beam evaporation technology, with a deposition rate of 0.1–1.0 Å / s, preferably 0.2–0.5 Å / s. Compared with existing technologies, the advantages of this invention are: the fabrication process of this self-powered solar-blind ultraviolet photodetector is simple and can be mass-produced. Furthermore, the device can achieve a self-powered response under zero-volt bias and a photoconductive response under bias mode, exhibiting low power consumption and high performance. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the gallium oxide / magnesium nickel oxide heterojunction photodetector obtained in Embodiment 1 of the present invention.

[0016] Figure 2 This is an IV logarithmic curve of the gallium oxide / magnesium nickel oxide heterojunction photodetector obtained in Example 1 of the present invention under dark conditions and different light intensities, with light intensities of 1 / 10 / 20 / 40 / 60 μW / cm² respectively. 2 .

[0017] Figure 3 These are the It curves of the gallium oxide / magnesium nickel oxide heterojunction photodetector obtained in Example 1 of this invention under zero bias and negative bias at different light intensities, with light intensities of 1 / 10 / 20 / 40 / 60 μW / cm². 2 (a) is zero bias, and (b) is negative bias.

[0018] Figure 4 These are the photoresponse curves of the gallium oxide / magnesium nickel oxide heterojunction photodetector obtained in Example 1 of this invention under zero bias and negative bias at different illumination intensities, with illumination intensities of 1 / 10 / 20 / 40 / 60 μW / cm² respectively. 2 (a) is zero bias, and (b) is negative bias.

[0019] Figure 5 These are data graphs of the gallium oxide / magnesium nickel oxide heterojunction photodetector obtained in Example 2 of the present invention. (a) is the IV curve, and (b) is the It curve at zero bias.

[0020] Figure 6 These are data graphs of the gallium oxide / magnesium nickel oxide heterojunction photodetector obtained in Example 3 of the present invention. (a) is the IV curve, and (b) is the It curve at zero bias. Detailed Implementation

[0021] This invention relates to a method for fabricating a self-powered solar-blind ultraviolet photodetector based on a gallium oxide / magnesium nickel oxide alloy heterojunction. To clearly illustrate the technical solution, detailed descriptions will follow with reference to embodiments and accompanying drawings. It should be specifically noted that the specific embodiments described are for understanding the invention only and are not intended to limit the scope of protection. Example 1

[0022] A gallium oxide / magnesium nickel oxide heterojunction photodetector, the device structure is as follows: Figure 1 As shown, it includes: an aluminum oxide substrate; a gallium oxide epitaxial layer deposited on the aluminum oxide substrate; a magnesium nickel oxide thin film layer deposited on the gallium oxide epitaxial layer; a first electrode forming an ohmic contact with the gallium oxide epitaxial layer; and a second electrode forming an ohmic contact with the magnesium nickel oxide thin film layer.

[0023] Gallium oxide epitaxial layers were prepared on alumina substrates using metal-organic chemical vapor deposition (MOCVD). The gallium source was triethylgallium; the oxygen source was oxygen; and the carrier gas was nitrogen. Gallium oxide is an n-type semiconductor, and the film thickness was 1 μm.

[0024] A magnesium-nickel-oxygen (MgO) thin film was deposited on a gallium oxide epitaxial layer using magnetron sputtering. The target material was a solid solution ceramic alloy of magnesium oxide and nickel oxide, with magnesium oxide comprising 30% by molar percentage. The growth temperature was 460 °C. The MgO thin film was a p-type semiconductor with a thickness of 100 nm.

[0025] The first and second electrodes were fabricated using electron beam evaporation, with a deposition rate of 0.5 Å / s for both. The first electrode, which forms an ohmic contact with the gallium oxide epitaxial layer, is a titanium-gold composite electrode, while the second electrode, which forms an ohmic contact with the magnesium-nickel-oxygen thin film layer, is a nickel-gold composite electrode.

[0026] Perform IV testing on the photodetector. Figure 2 As shown, the overall dark current of this photodetector under dark conditions is less than 10. -13 A, exhibiting an excellent signal-to-noise ratio. Under 254 nm illumination, the detector successfully achieved a self-powered response under zero-volt bias and a photoconductive response under bias mode.

[0027] The photodetector was subjected to It tests under different light intensities. Figure 3 As shown, the photocurrent generated by the detector gradually increases with the increase of light intensity in both self-powered mode and biased mode. The highest current reaches 10.21 nA in self-powered mode and 22.76 nA in biased mode.

[0028] Calculate the photoresponsivity of the photodetector for different light intensities in self-powered and biased modes. For example... Figure 4 As shown, the photodetector in this embodiment has a self-powered responsivity of up to 117 mA / W and a bias responsivity of up to 265 mA / W, demonstrating the low power consumption and high performance of the detector. Example 2

[0029] In this embodiment, the preparation conditions of the experimental device used are the minimum value of the stated condition range.

[0030] A gallium oxide / magnesium nickel oxide heterojunction photodetector includes: an aluminum oxide substrate; a gallium oxide epitaxial layer deposited on the aluminum oxide substrate; a magnesium nickel oxide thin film layer deposited on the gallium oxide epitaxial layer; a first electrode forming an ohmic contact with the gallium oxide epitaxial layer; and a second electrode forming an ohmic contact with the magnesium nickel oxide thin film layer.

[0031] Gallium oxide epitaxial layers were prepared on alumina substrates using metal-organic chemical vapor deposition (MOCVD). The gallium source was triethylgallium; the oxygen source was oxygen; and the carrier gas was nitrogen. Gallium oxide is an n-type semiconductor, and the film thickness was 100 nm.

[0032] A magnesium-nickel-oxygen (MgO) thin film was deposited on a gallium oxide epitaxial layer using magnetron sputtering. The target material was a solid solution ceramic alloy of magnesium oxide and nickel oxide, with magnesium oxide comprising 10% by molar percentage. The growth temperature was 460 °C. The MgO thin film was a p-type semiconductor with a thickness of 50 nm.

[0033] The first and second electrodes were fabricated using electron beam evaporation. The first electrode, forming an ohmic contact with the gallium oxide epitaxial layer, was a titanium-gold composite electrode, and the second electrode, forming an ohmic contact with the magnesium-nickel-oxygen thin film layer, was a nickel-gold composite electrode. The deposition rate for both was 0.1 Å / s.

[0034] Perform IV and It tests on the photodetector. Figure 5 (a) and Figure 5 As shown in (b), the overall dark current of the photodetector under dark conditions is less than 10. -12 A also exhibits photoelectric response and generates photocurrent under 254 nm illumination, but its overall performance is weaker than that of Example 1. Example 3

[0035] In this embodiment, the preparation conditions of the experimental device used are the maximum value of the stated condition range.

[0036] A gallium oxide / magnesium nickel oxide heterojunction photodetector includes: an aluminum oxide substrate; a gallium oxide epitaxial layer deposited on the aluminum oxide substrate; a magnesium nickel oxide thin film layer deposited on the gallium oxide epitaxial layer; a first electrode forming an ohmic contact with the gallium oxide epitaxial layer; and a second electrode forming an ohmic contact with the magnesium nickel oxide thin film layer.

[0037] Gallium oxide epitaxial layers were prepared on alumina substrates using metal-organic chemical vapor deposition (MOCVD). The gallium source was triethylgallium; the oxygen source was oxygen; and the carrier gas was nitrogen. Gallium oxide is an n-type semiconductor, and the film thickness was 2 μm.

[0038] A magnesium-nickel-oxygen (MgO) thin film was deposited on a gallium oxide epitaxial layer using magnetron sputtering. The target material was a solid solution ceramic alloy of magnesium oxide and nickel oxide, with magnesium oxide comprising 45% by molar percentage. The growth temperature was 460 °C. The MgO thin film was a p-type semiconductor with a thickness of 200 nm.

[0039] The first and second electrodes were fabricated using electron beam evaporation. The first electrode, forming an ohmic contact with the gallium oxide epitaxial layer, was a titanium-gold composite electrode, and the second electrode, forming an ohmic contact with the magnesium-nickel-oxygen thin film layer, was a nickel-gold composite electrode. The deposition rate for both was 0.5 Å / s.

[0040] Perform IV and It tests on the photodetector. Figure 6 (a) and Figure 6As shown in (b), the photodetector also stably generates photoelectric response and photocurrent under 254 nm illumination, but its overall performance is weaker than that of Examples 1 and 2.

[0041] In summary, this invention provides a gallium oxide / magnesium nickel oxide heterojunction photodetector and its fabrication method. The technical solution provided by this invention can construct a high-quality gallium oxide / magnesium nickel oxide heterojunction, establishing a strong built-in electric field at the interface, which can efficiently separate photogenerated carriers and suppress recombination. The technical solution of Embodiment 1 provided by this invention is the optimal solution. The photodetector constructed based on this heterojunction system can achieve a synergistic improvement in high responsivity, fast response, and low power consumption.

[0042] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made to this invention based on design requirements and other factors. All such modifications, equivalent substitutions, or improvements made without departing from the spirit and principles of this invention should be covered within the scope of protection of this invention.

Claims

1. A gallium oxide / magnesium nickel oxide heterojunction photodetector, characterized in that, include: Alumina substrate; Gallium oxide epitaxial layer deposited on an alumina substrate; A magnesium-nickel-oxygen thin film layer deposited on a gallium oxide epitaxial layer; The first electrode forms an ohmic contact with the gallium oxide epitaxial layer; the second electrode forms an ohmic contact with the magnesium nickel oxide thin film layer.

2. The gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 1, characterized in that, The gallium oxide epitaxial layer is an n-type semiconductor with a thickness of 100 nm to 2 μm.

3. The gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 1, characterized in that, The magnesium-nickel-oxygen thin film layer is a p-type semiconductor with a thickness of 50 nm to 200 nm.

4. The gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 1, characterized in that, The first electrode is one or more of copper, silver, titanium, nickel, aluminum, indium, and gold.

5. The gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 1, characterized in that, The second electrode is one or more of copper, silver, titanium, nickel, aluminum, indium, and gold.

6. A method for fabricating a gallium oxide / magnesium nickel oxide heterojunction photodetector based on any one of claims 1-5, characterized in that, The process includes the following steps: preparing a gallium oxide epitaxial layer on an aluminum oxide substrate, depositing a magnesium nickel oxide thin film layer on the gallium oxide epitaxial layer to form a heterojunction between the gallium oxide epitaxial layer and the magnesium nickel oxide thin film layer, and preparing a first electrode and a second electrode with ohmic contact on the gallium oxide epitaxial layer and the magnesium nickel oxide thin film layer, respectively.

7. The method for fabricating a gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 6, characterized in that, The gallium oxide epitaxial layer is prepared on an alumina substrate by metal-organic chemical vapor deposition, with triethylgallium or trimethylgallium as the gallium source, oxygen or ultrapure water as the oxygen source, and nitrogen or argon as the carrier gas.

8. The method for fabricating a gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 6, characterized in that, The magnesium-nickel-oxygen thin film layer is prepared by magnetron sputtering technology, and the target material is an alloy solid solution ceramic of magnesium oxide and nickel oxide, wherein the molar percentage of magnesium oxide is 10%~45%.

9. The method for fabricating a gallium oxide / magnesium nickel oxide heterojunction photodetector according to claim 6, characterized in that, Both the first and second electrodes were prepared by electron beam evaporation technology with a deposition rate of 0.1~1.0 Å / s.

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