(GaMe).SUB.2.O.SUB.3 .ternary alloy material, its preparation method and application in solar-blind ultraviolet photodetector

Abstract

A (GaMe).sub.2O.sub.3 ternary alloy material, its preparation method and application in a solar-blind ultraviolet photodetector are provided. The (GaMe).sub.2O.sub.3 ternary alloy material of the present invention is formed by solid solution of Ga.sub.2O.sub.3 and Me.sub.2O.sub.3 in a molar ratio of 99:1 to 50:50, wherein the Me is any one of Lu, Sc, or Y. The (GaMe).sub.2O.sub.3 ternary alloy material of the present invention can be used to prepare the active layer of a solar-blind ultraviolet photodetector. In the present invention, the band gap of Me.sub.2O.sub.3 is higher than that of Ga.sub.2O.sub.3, and Ga.sup.3+ ions in Ga.sub.2O.sub.3 are partially replaced by Me.sup.3+ ions to obtain a higher band gap (GaMe).sub.2O.sub.3 ternary alloy material to reduce the dark current of the device and promote the blue shift of the cut-off wavelength to within 280 nm.

Claims

1. A (GaMe).sub.2O.sub.3 ternary alloy material, comprising solid solutions of Ga.sub.2O.sub.3 and Me.sub.2O.sub.3 with a molar ratio of 99:1 to 50:50, wherein Me is one element selected from Lu, Sc and Y.

2. The (GaMe).sub.2O.sub.3 ternary alloy material, as recited in claim 1, wherein a molar ratio of the Ga.sub.2O.sub.3:Me.sub.2O.sub.3 is at a range of 95:5 to 70:30.

3. A method for preparing the (GaMe).sub.2O.sub.3 ternary alloy material, as recited in claim 1, specifically comprising steps of: (A) weighing powders of the Ga.sub.2O.sub.3 and Me.sub.2O.sub.3 with the molar ratio, placing the powders in a ball milling tank, adding deionized water and performing ball milling to obtain a uniformly mixed powder; (B) screening the uniformly mixed powder solution in step (A) to remove milling zirconia balls and placing the uniformly mixed powder solution in a vacuum drying oven, after drying, cooling to room temperature, then crushing and pressing into a wafer; and (C) in an air atmosphere, placing the wafer obtained in step (B) in a vacuum tube furnace and sintering at 1000 to 1500° C. for 1 to 4 hours to obtain the (GaMe).sub.2O.sub.3 ternary alloy material.

4. A method for preparing a solar-blind ultraviolet photodetector comprising the (GaMe).sub.2O.sub.3 ternary alloy material as recited in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structural diagram of a solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 1 of the present invention.

(2) FIG. 2 is a comparison chart of X-ray diffraction (XRD) of the (GaLu).sub.2O.sub.3 film in Example 1 of the present invention and the pure Ga.sub.2O.sub.3 film in Comparative Example 1.

(3) FIG. 3 is a transmission spectrum diagram of the (GaLu).sub.2O.sub.3 ternary alloy film in Example 1 of the present invention vs. the pure Ga.sub.2O.sub.3 film in Comparative Example 1.

(4) FIG. 4 is a (αhv).sup.2-hv relationship diagram of the (GaLu).sub.2O.sub.3 ternary alloy film in Example 1 of the present invention vs. the pure Ga.sub.2O.sub.3 film in Comparative Example 1.

(5) FIG. 5 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 1 of the present invention.

(6) FIG. 6 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 2 of the present invention.

(7) FIG. 7 is a comparison diagram of the spectral responsivity test results of the (GaLu).sub.2O.sub.3-based photodetector in Example 1 of the present invention and the pure Ga.sub.2O.sub.3-based solar-blind ultraviolet photodetector in Comparative Example 1.

(8) FIG. 8 is a schematic structural view of a solar-blind ultraviolet photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in Example 5 of the present invention.

(9) FIG. 9 is an X-ray diffraction (XRD) diagram of the (GaSc).sub.2O.sub.3 ternary alloy thin film prepared in Example 5 of the present invention vs. the pure Ga.sub.2O.sub.3 thin film prepared in Comparative Example 1.

(10) FIG. 10 is an I-V curve of a solar-blind UV photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in Example 5 of the present invention.

(11) FIG. 11 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in Example 5 of the present invention.

(12) FIG. 12 is an I-V curve of a solar-blind UV photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in Example 6 of the present invention.

(13) FIG. 13 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in Example 6 of the present invention.

(14) FIG. 14 is a schematic structural view of a solar-blind photodetector based on (GaY).sub.2O.sub.3 ternary alloy in Example 9 of the present invention.

(15) FIG. 15 is an X-ray diffraction (XRD) full spectrum chart of the amorphous (GaY).sub.2O.sub.3 film in Example 9 of the present invention vs. pure Ga.sub.2O.sub.3 thin film prepared in Comparative Example 1.

(16) FIG. 16 is an I-V curve of a solar-blind ultraviolet photodetector based on (GaY).sub.2O.sub.3 ternary alloy in Example 9 of the present invention.

(17) FIG. 17 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaY).sub.2O.sub.3 ternary alloy in Example 9 of the present invention.

(18) FIG. 18 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaY).sub.2O.sub.3 ternary alloy in Example 10 of the present invention.

(19) FIG. 19 is an XRD full spectrum of the amorphous (GaLu).sub.2O.sub.3 thin film prepared in Example 13 of the present invention.

(20) FIG. 20 is an I-V curve of a solar-blind UV photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 13 of the present invention.

(21) FIG. 21 is a graph of time t-current I response of a solar-blind UV photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 13 of the present invention.

(22) FIG. 22 is a graph of time t-current I response of a solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 14 of the present invention.

(23) FIG. 23 is an I-V curve of a pure Ga.sub.2O.sub.3 based solar-blind ultraviolet photodetector in Comparative Example 1 of the present invention.

(24) FIG. 24 is a graph of time t-current I response of the pure Ga.sub.2O.sub.3 based solar-blind ultraviolet photodetector in Comparative Example 1 of the present invention.

(25) FIG. 25 is a comparison of the spectral responsivity of solar-blind UV photodetectors based on (GaSc).sub.2O.sub.3 solar-blind in Example 5 of the present invention and pure Ga.sub.2O.sub.3 in Comparative Example 1.

(26) FIG. 26 is a comparison of the spectral responsivity of solar blind ultraviolet photodetectors based on (GaY).sub.2O.sub.3 in Example 9 of the present invention and pure Ga.sub.2O.sub.3 in Comparative Example 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(27) The embodiments of the present invention will be described in detail below with reference to the drawings. This embodiment case is implemented on the premise of the technical solution of the present invention, and a detailed embodiment and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment cases.

(28) The main components of the sapphire substrate used in the following embodiments of the present invention is alumina (Al.sub.2O.sub.3); wherein c-Al.sub.2O.sub.3 represents c-plane sapphire, and m-Al.sub.2O.sub.3 represents m-plane sapphire. A thickness of the sapphire substrate in the present invention is preferably 0.35 to 0.45 mm.

(29) The light-dark current ratio (I.sub.light/I.sub.dark) and the detection rate (D*) involved in the following embodiments of the present invention are calculated by the I-V and I-t test results, and the detection rate is calculated according to a peak wavelength of the responsivity. The calculation formula is as follows:

(30) $D^{*}=\frac{{\mathrm{RS}}^{1/2}}{{\left(2{\mathrm{qI}}_{\mathrm{dark}}\right)}^{1/2}},$
where R refers to a peak responsivity, S refers to a photosensitive area of the photodetector, I.sub.dark refers to a dark current, and q refers to an electron charge.

Example 1

(31) A (GaLu).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Lu.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is as follows:

(32) 1.1 According to the molar ratio of Ga.sub.2O.sub.3:Lu.sub.2O.sub.3=70:30, weigh 5.236 g of Ga.sub.2O.sub.3 powder and 4.963 g of Lu.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then put in a ball mill tank of planetary ball mill wherein ball milling media are zirconia ceramic balls, ball mill for 4 h to obtain mixed powder;

(33) 1.2 Sieve the mixed powder to remove the zirconia balls, place in a vacuum drying oven, vacuum dry at 110° C. for 12 h, take it out and cool to a room temperature, add 1 g of deionized water, and grind thoroughly with a mortar, and then press with a tablet press at 8 M Pa pressure to form a wafer with a diameter of 27.5 mm and a thickness of 2 mm;

(34) 1.3 Place the wafer into a crucible in a vacuum tube furnace and place a powder (15.000 g) of an identical composition around the wafer, Heat the tube furnace to 1300° C. and hold for 3 hours, and then naturally cool to a room temperature to obtain the (GaLu).sub.2O.sub.3 ternary alloy material.

(35) The (GaLu).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. As shown in FIG. 1, a solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel Metal Au electrodes, wherein: the active layer is (−201) oriented (GaLu).sub.2O.sub.3 ternary alloy film, and the (−201) oriented (GaLu).sub.2O.sub.3 ternary alloy film is deposited using the (GaLu).sub.2O.sub.3 ternary alloy material; the thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 50 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(36) The solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy described above in this embodiment is prepared by the following method, including the following steps:

(37) 2.1 Using the (GaLu).sub.2O.sub.3 ternary alloy material prepared in step 1.3 as a laser ablation target, it was loaded into a vacuum chamber together with a sapphire substrate that was ultrasonically cleaned for 15 min with acetone, absolute ethanol, and deionized water, respectively, and pump the chamber down to 10.sup.−4 Pa;

(38) 2.2 After the substrate temperature is raised to 700° C., oxygen is introduced to maintain the gas pressure at 4 Pa during the entire film deposition process; then the substrate and target are set to rotate, and the laser output energy and pulse repetition frequency are set to 300 mJ/pulse and 5 Hz, respectively, and then the laser is turned on to start depositing (GaLu).sub.2O.sub.3 ternary alloy thin film. After 30 minutes of deposition, the oxygen and heating were turned off, and finally the sample was naturally cooled to room temperature in a vacuum and taken out;

(39) 2.3 Place the obtained (GaLu).sub.2O.sub.3 ternary alloy film on the mask plate and install it in the vacuum chamber of the vacuum evaporation machine, then install the tungsten boat and feed it with the evaporation source—metal Au 0.15 g, close the vacuum chamber, and turn on the mechanical pump, fore-stage valve, molecular pump, and pump the chamber to below 10.sup.−4 Pa. Then turn on the evaporation power, slowly increase the current until the metal Au melts, and then keep the current constant and open the baffle to start evaporation. After the metal Au is evaporated, the current is slowly reduced, the evaporation source is closed, the molecular pump, the fore-stage valve, and the mechanical pump are turned off, and then the air valve is opened to flow air into the chamber. Finally the solar-blind ultraviolet photodetector based on the (GaLu).sub.2O.sub.3 ternary alloy is obtained.

(40) The XRD survey-scan spectrum of the (GaLu).sub.2O.sub.3 ternary alloy thin film prepared in this example is shown in FIG. 2. It can be seen that in addition to the (0003), (0006) and (0009) three diffraction peaks of the c-plane sapphire substrate, there are and only three diffraction peaks, which are located near 18.9°, 38.3° and 59.1°, respectively. The standard XRD spectrum (JCPDS File No. 41-1103) shows that these three diffraction peaks correspond to the (−201), (−402), and (−603) crystal planes of Ga.sub.2O.sub.3, respectively, indicating that (−201) oriented (GaLu).sub.2O.sub.3 ternary alloy thin film was successfully prepared in this example.

(41) FIG. 3 shows the transmission spectra of (GaLu).sub.2O.sub.3 and pure Ga.sub.2O.sub.3. As shown in FIG. 3, the transmittance of (GaLu).sub.2O.sub.3 and pure Ga.sub.2O.sub.3 in the infrared and visible light regions are both above 90%. The absorption edge of (GaLu).sub.2O.sub.3 thin film is near 235 nm, which is obviously blue-shifted with respect to the absorption edge (˜255 nm) of pure Ga.sub.2O.sub.3 thin film. Because gallium oxide is a direct band gap semiconductor, the band gap Eg of the thin film can be obtained by the relationship (αhv).sup.2∝(hv-Eg), where hv represents the incident photon energy and a represents the absorption coefficient. The curve of (αhv).sup.2 vs. hv is shown in FIG. 4. By linear extrapolation, the band gap of (GaLu).sub.2O.sub.3 film is estimated as 5.2 eV, while the band gap of pure Ga.sub.2O.sub.3 is 4.9 eV. It can be seen that the doping of Lu can significantly increase the band gap of gallium oxide. This is because the band gap of Lu.sub.2O.sub.3 (5.5 eV) is larger than that of Ga.sub.2O.sub.3 (4.9 eV).

(42) Further, a voltage of 10 V was applied between the electrodes of the device prepared in this example while the surface of the sample was irradiated with monochromatic light to perform photoelectric performance tests. FIGS. 5 and 7 are the time-current and wavelength-responsivity curves of the device, respectively. The results show that the device has obvious detection ability for solar-blind ultraviolet light. Compared with pure Ga.sub.2O.sub.3 solar-blind ultraviolet photodetector, it has lower dark current (I.sub.dark<0.2 pA) and faster response speed. The device's recovery relaxation time τ.sub.d2 is 0.190 s, and its peak response wavelength (245 nm) and the cut-off wavelength (270 nm) are blue-shifted, showing a more sensitive detection ability for solar-blind ultraviolet light. This is due to the (GaLu).sub.2O.sub.3 film having a wider band gap and fewer oxygen vacancy defects than pure Ga.sub.2O.sub.3. The wider band gap causes the dark current of the device to be significantly reduced, and the peak response wavelength and cut-off wavelength are blue-shifted. The reduction of oxygen vacancies in the film reduces the concentration of the trap centers, resulting in a significant reduction in the relaxation time of the device.

(43) In summary, (GaLu).sub.2O.sub.3-based photodetectors have lower dark current, faster response speed, and shorter cut-off wavelength than pure Ga.sub.2O.sub.3-based photodetectors, showing more sensitive and faster responding detection capability to solar-blind ultraviolet light.

Example 2

(44) The (GaLu).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Lu.sub.2O.sub.3 powder with a molar ratio of 95:5 by solid phase sintering. The specific method is as follows:

(45) 1.1 According to the molar ratio of Ga.sub.2O.sub.3:Lu.sub.2O.sub.3=95:5, weigh 8.995 g Ga.sub.2O.sub.3 powder and 1.005 g Lu.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then put it in a ball mill tank in a planetary ball mill (ball milling media are zirconia ceramic balls), ball mill for 4 h to obtain mixed powder;

(46) 1.2 The mixed powder obtained in step 1.1 of this embodiment is made into the (GaLu).sub.2O.sub.3 ternary alloy material by using the same treatment process of step 1.2 and step 1.3 of the Example 1 in sequence.

(47) The (GaLu).sub.2O.sub.3 ternary alloy material described above in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes from bottom to top, where: The active layer is (−201) oriented (GaLu).sub.2O.sub.3 ternary alloy film, and the (−201) oriented (GaLu).sub.2O.sub.3 ternary alloy film is deposited using the (GaLu).sub.2O.sub.3 ternary alloy material; The thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 55 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(48) The solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy described above in this embodiment is prepared by the following method, including the following steps:

(49) The solar-blind photodetector based on the (GaLu).sub.2O.sub.3 ternary alloy of this example was prepared in the same way as in Example 1.

(50) A voltage of 10 V was applied between the electrodes of the device prepared in this example while the surface of the sample was irradiated with monochromatic light to perform photoelectric performance tests. The results show that the dark current of the device is very low (I.sub.dark<0.2 pA), the response speed is fast, and the device's relaxation response time τ.sub.d2 is 0.228 s, which shows a good detection ability for solar-blind ultraviolet light. The test results are shown in FIG. 6.

Example 3

(51) A (GaLu).sub.2O.sub.3 ternary alloy material in this embodiment is prepared by using the same raw material ratio and method as in Example 1.

(52) The (GaLu).sub.2O.sub.3 ternary alloy material described above in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes from bottom to top, where the active layer is a (−201)-oriented (GaLu).sub.2O.sub.3 ternary alloy film, and the (−201)-oriented (GaLu).sub.2O.sub.3 ternary alloy film is deposited using the (GaLu).sub.2O.sub.3 ternary alloy material; The thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 300 nm, the thickness of the parallel metal Au electrodes is 30 nm, and the spacing of the parallel metal Au electrodes is 50 μm.

(53) The solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy described above in this embodiment is prepared by the following method, including the following steps:

(54) 2.1 Using the (GaLu).sub.2O.sub.3 ternary alloy material prepared in this example as a laser ablation target, it was loaded into a vacuum chamber together with a sapphire substrate that was ultrasonically cleaned with acetone, absolute ethanol, and deionized water, etc. for 15 min. And the chamber was evacuated to 10.sup.−4 Pa;

(55) 2.2 After the substrate temperature is raised to 500° C., oxygen is introduced to maintain the gas pressure at 1 Pa during the entire film deposition process; then the substrate and the target are set to rotate, and the laser output energy and pulse repetition frequency are set to 500 mJ/pulse and 5 Hz, respectively, and then the laser is turned on to start depositing (GaLu).sub.2O.sub.3 ternary alloy thin film. After 30 minutes of deposition, the oxygen and heating were turned off, and finally the sample was naturally cooled to room temperature in a vacuum and taken out;

(56) 2.3 Place the obtained (GaLu).sub.2O.sub.3 ternary alloy film on the mask plate and install it into the vacuum chamber of the vacuum evaporation machine, then install the tungsten boat and feed it with the evaporation source—metal Au 0.10 g, close the vacuum chamber and turn on the mechanical pump, fore-stage valve, molecular pump, and pump the chamber to below 10.sup.−4 Pa. Then turn on the evaporation power, slowly increase the current until the metal Au melts, and then keep the current constant and open the baffle to start evaporation. After the metal Au is evaporated, the current is slowly reduced, the evaporation source is closed, the molecular pump, the fore-stage valve, and the mechanical pump are turned off, and then the air valve is open to flow air into the chamber. Finally the solar-blind ultraviolet photodetector based on the (GaLu).sub.2O.sub.3 ternary alloy is obtained.

Example 4

(57) A (GaLu).sub.2O.sub.3 ternary alloy material in this embodiment is prepared by using the same raw material ratio and method as in Example 1.

(58) The (GaLu).sub.2O.sub.3 ternary alloy material described above in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes from bottom to top, where: The active layer is a (−201)-oriented (GaLu).sub.2O.sub.3 ternary alloy film, and the (−201)-oriented (GaLu).sub.2O.sub.3 ternary alloy film is deposited using the (GaLu).sub.2O.sub.3 ternary alloy material; The thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 200 nm, the thickness of the parallel metal Au electrode is 70 nm, and the spacing of the parallel metal Au electrodes is 100 μm.

(59) The solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment is prepared by the following method, including the following steps:

(60) 2.1 Using the (GaLu).sub.2O.sub.3 ternary alloy material prepared in this example as a laser ablation target, it was loaded into a vacuum chamber together with a sapphire substrate that was ultrasonically cleaned with acetone, absolute ethanol, and deionized water, etc. for 15 min. And the chamber was evacuated to 10.sup.−4 Pa;

(61) 2.2 After the substrate temperature is raised to 300° C., oxygen is introduced to maintain the gas pressure at 8 Pa throughout the film deposition process; then the substrate and the target are set to rotate, and the laser output energy and pulse repetition frequency are set to 600 mJ/pulse and 5 Hz, respectively, and then the laser is turned on to start depositing (GaLu).sub.2O.sub.3 ternary alloy thin film. After 30 minutes of deposition, the oxygen and heating were turned off, and finally the sample was naturally cooled to room temperature in a vacuum and taken out;

(62) 2.3 Place the obtained (GaLu).sub.2O.sub.3 ternary alloy film on the mask plate and install it into the vacuum chamber of the vacuum evaporation machine, then install the tungsten boat and feed it with the evaporation source-metal Au 0.25 g, close the vacuum chamber, and turn on the mechanical pump, fore-stage valve, molecular pump, and pump the chamber to below 10.sup.−4 Pa. Then turn on the evaporation power, slowly increase the current until the metal Au melts, and then keep the current constant and open the baffle to start evaporation. After the metal Au is evaporated, the current is slowly reduced, the evaporation source is closed, the molecular pump, the fore-stage valve, and the mechanical pump are turned off, and then the air valve is opened to flow air into the chamber. Finally the solar-blind photodetector based on the (GaLu).sub.2O.sub.3 ternary alloy is obtained.

Example 5

(63) A (GaSc).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Sc.sub.2O.sub.3 powder with a molar ratio of 95:5 by solid phase sintering. The specific method is as follows:

(64) 1.1 According to the molar ratio of Ga.sub.2O.sub.3:Sc.sub.2O.sub.3=95:5, weigh 9.627 g Ga.sub.2O.sub.3 powder and 0.373 g Sc.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then put it in a ball mill tank in a planetary ball mill (the ball milling media are zirconia ceramic balls), ball mill for 4 h to obtain mixed powder;

(65) 1.2 Sieve the mixed powder to remove the zirconia balls, place it in a vacuum drying oven, vacuum dry at 110° C. for 12 h, take it out and cool to room temperature, add 1 g of deionized water, and grind it thoroughly with a mortar, and then press it using a tablet press at 8 M Pa pressure to form a wafer with a diameter of 27.5 mm and a thickness of 2 mm;

(66) 1.3 Place the wafer into a crucible in a vacuum tube furnace and place a powder (15.000 g) of the same composition around it. The tube furnace was heated to 1300° C. and kept for 3 hours, and then naturally cooled to room temperature to obtain the (GaSc).sub.2O.sub.3 ternary alloy material.

(67) The (GaSc).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. As shown in FIG. 8, a solar-blind photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel Metal Au electrodes, wherein: the active layer is (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy film, and the (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy film is deposited using the (GaSc).sub.2O.sub.3 ternary alloy material; the thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 50 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(68) The solar-blind photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in this embodiment is manufactured by the following method, and the steps are as follows:

(69) 2.1 Using the (GaSc).sub.2O.sub.3 ternary alloy material prepared in step 1.3 as a laser ablation target, it was loaded into a vacuum chamber together with a sapphire substrate that was ultrasonically cleaned with acetone, absolute ethanol, and deionized water, etc. for 15 min, and pump the chamber down to 10.sup.−4 Pa;

(70) 2.2 After the substrate temperature is raised to 700° C., oxygen is introduced to maintain the gas pressure at 4 Pa during the entire film deposition process; then the substrate and target are set to rotate, and the laser output energy and pulse repetition frequency are set to 300 mJ/pulse and 5 Hz, respectively, and then the laser is turned on to start depositing (GaSc).sub.2O.sub.3 ternary alloy thin film. After 30 minutes of deposition, the oxygen and heating were turned off, and finally the sample was naturally cooled to room temperature in a vacuum and taken out;

(71) 2.3 Place the obtained (GaSc).sub.2O.sub.3 ternary alloy film on the mask plate and install it into the vacuum chamber of the vacuum evaporation machine, then install the tungsten boat and feed it with the evaporation source-metal Au 0.15 g, close the vacuum chamber and turn on the mechanical pump, fore-stage valve, molecular pump, and pump the chamber to below 10.sup.−4 Pa. Then turn on the evaporation power, slowly increase the current until the metal Au melts, and then keep the current constant and open the baffle to start evaporation. After the metal Au is evaporated, the current is slowly reduced, the evaporation source is closed, the molecular pump, the fore-stage valve, and the mechanical pump are turned off, and then the air valve is opened to flow air into the chamber. Finally the solar-blind ultraviolet photodetector based on the (GaSc).sub.2O.sub.3 ternary alloy is obtained.

(72) The XRD survey-scan spectrum of the (GaSc).sub.2O.sub.3 ternary alloy thin film prepared in this example is shown in FIG. 9. It can be seen that in addition to the diffraction peaks of the c-plane sapphire substrate, there are only three diffraction peaks, which are located near 18.9°, 38.3°, and 59.1°, respectively. Comparing with the standard XRD spectrum of Ga.sub.2O.sub.3 (JCPDS File No. 41-1103), it can be seen that these three diffraction peaks correspond to the (−201), (−402) and (−603) crystal planes of Ga.sub.2O.sub.3, respectively, indicating that the (−201) oriented (GaSc).sub.2O.sub.3 ternary alloy film was successfully prepared in this example.

(73) FIG. 10 shows the I-V curve of a solar-blind UV photodetector based on the (GaSc).sub.2O.sub.3 ternary alloy produced in this example. It can be clearly seen that the I-V curve under illumination is non-linear, indicating that Au and (GaSc).sub.2O.sub.3 films form a Schottky contact. FIG. 11 shows the time-current response curve of the device at 10V bias voltage. It can be seen from FIG. 11 that under a 10 V bias voltage, the dark current of this device is very small (<0.2 pA), which is much smaller than the dark current of a pure Ga.sub.2O.sub.3-based photodetector (˜10.6 pA). This is because that the band gap of Sc.sub.2O.sub.3 (5.9 eV) is larger than that of Ga.sub.2O.sub.3 (4.9 eV), and the doping of Sc.sup.3+ ions can significantly increase the band gap of Ga.sub.2O.sub.3, thus making the dark current of photodetectors based on (GaSc).sub.2O.sub.3 with wider band gaps significantly reduced. At the same time, we use the double exponential relaxation equation to fit the curve, and the device relaxation response times τ.sub.r2 and τ.sub.d2 are 0.202 s and 0.228 s, respectively, which are significantly shorter than the relaxation response times of the pure Ga.sub.2O.sub.3-based 0 based photodetector (τ.sub.r2=0.579 s τ.sub.d2=0.661 s). This is because that the binding energy between Sc.sup.3+ ions and O.sup.2− ions is stronger than that between Ga.sup.3+ ions and O.sup.2− ions, so that the (GaSc).sub.2O.sub.3 ternary alloy film has a lower oxygen vacancy concentration than the pure Ga.sub.2O.sub.3 film. The lower concentration of oxygen vacancies leads to fewer trap centers in the film, which results in a significantly faster response speed of the device. FIG. 25 is the wavelength-responsivity curve of (GaSc).sub.2O.sub.3 and pure Ga.sub.2O.sub.3 based photodetectors. Benefiting from the relatively wider band gap of (GaSc).sub.2O.sub.3, the peak response wavelength (245 nm) and cutoff wavelength of (GaSc).sub.2O.sub.3 based photodetectors (274 nm) are obviously blue shifted compared with the pure Ga.sub.2O.sub.3-based photodetector, which shows that it is more sensitive to the solar-blind ultraviolet light. In summary, (GaSc).sub.2O.sub.3-based photodetectors have lower dark current, faster response speed and shorter cut-off wavelength compared to pure Ga.sub.2O.sub.3-based photodetectors, showing more sensitive and faster detection capability to solar-blind ultraviolet light.

Example 6

(74) The (GaSc).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Sc.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is as follows:

(75) 1.1 According to the molar ratio of Ga.sub.2O.sub.3:Sc.sub.2O.sub.3=70:30, weigh 7.603 g Ga.sub.2O.sub.3 powder and 2.397 g Sc.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then put it into a ball mill tank in a planetary ball mill (the ball milling medium is zirconia ceramic balls), ball mill for 4 h to obtain mixed powder;

(76) 1.2 Using the same treatment process of step 1.2 and step 1.3 of Example 5 in turn, the mixed powder obtained in step 1.1 of this example is made into the (GaSc).sub.2O.sub.3 ternary alloy material.

(77) The (GaSc).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind photodetector. A solar-blind photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes from bottom to top, wherein: The active layer is a (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy film, and the (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy film is deposited using the (GaSc).sub.2O.sub.3 ternary alloy material; The thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 55 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(78) The solar-blind photodetector based on the (GaSc).sub.2O.sub.3 ternary alloy described above in this embodiment is prepared by the same method as in Example 5.

(79) A voltage of 10 V was applied between the electrodes of the device prepared in this example while the surface of the sample was irradiated with monochromatic light to perform photoelectric performance tests. The results show that the dark current of the device is very low (I.sub.dark<0.2 pA), and the response speed is relatively fast. The relaxation response times τ.sub.r2 and τ.sub.d2 of the device are 0.171 s and 0.197 s, respectively, showing good detection ability for solar-blind UV light. The test results are shown in FIG. 12 and FIG. 13, respectively.

Example 7

(80) A (GaSc).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Sc.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is the same as that of Example 6.

(81) The (GaSc).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind ultraviolet photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Al electrodes from bottom to top, wherein: The active layer is a (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy film, and the (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy film is deposited using the (GaSc).sub.2O.sub.3 ternary alloy material; The thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 300 nm, the thickness of the parallel metal Al electrode is 30 nm, and the spacing of the parallel metal Al electrodes is 50 μm.

(82) The preparation method of the (GaSc).sub.2O.sub.3 ternary alloy-based solar-blind ultraviolet photodetector described in this embodiment is basically the same as the preparation method of the (GaLu).sub.2O.sub.3 ternary alloy-based solar-blind ultraviolet photodetector of Example 3. The only difference is that the laser ablation target uses (GaSc).sub.2O.sub.3 ternary alloy material made in this embodiment, and the evaporation source in this embodiment is metal Al, and the amount is 0.10 g.

Example 8

(83) A (GaSc).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Sc.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is the same as that of Example 6.

(84) The (GaSc).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Pt electrodes from bottom to top, wherein: The active layer is a (−201)-oriented (GaSc).sub.2O.sub.3 ternary alloy thin film, the thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 200 nm, the thickness of the parallel metal Pt electrode is 70 nm, and the spacing of the parallel metal Pt electrodes is 100 μm.

(85) The preparation method of the solar-blind ultraviolet photodetector based on (GaSc).sub.2O.sub.3 ternary alloy in this embodiment is basically the same as the preparation method of the solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 4. Only difference is that in this embodiment, the laser ablation target uses (GaSc).sub.2O.sub.3 ternary alloy material made in this embodiment, and the evaporation source in this embodiment is metal Pt, and the amount is 0.25 g.

Example 9

(86) The (GaY).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Y.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is as follows:

(87) 1.1 According to the molar ratio Ga.sub.2O.sub.3:Y.sub.2O.sub.3=70:30, weigh 6.595 g of Ga.sub.2O.sub.3 powder and 3.401 g of Y.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then place in a ball mill tank in a planetary ball mill, wherein the ball milling medium is zirconia Ceramic balls, ball mill for 4 h to obtain mixed powder.

(88) 1.2 Sieve the mixed powder to remove the zirconia balls, place it in a vacuum drying oven, vacuum dry at 110° C. for 12 h, take out and cool to a room temperature, add 1 g of deionized water, and grind thoroughly with a mortar, and then press with a tablet press at 8 M Pa pressure to form a wafer with a diameter of 27.5 mm and a thickness of 2 mm;

(89) 1.3 Place the wafer into a crucible in a vacuum tube furnace and place a powder (15.000 g) of an identical composition around the wafer. Heat the tube furnace to 1300° C. and hold for 3 hours, and then naturally cool to room temperature to obtain the (GaY).sub.2O.sub.3 ternary alloy material.

(90) The (GaY).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. As shown in FIG. 14, a solar-blind photodetector based on (GaY).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel Metal Au electrodes, wherein: the active layer is an amorphous (GaY).sub.2O.sub.3 ternary alloy thin film, and the amorphous (GaY).sub.2O.sub.3 ternary alloy thin film is deposited using the (GaY).sub.2O.sub.3 ternary alloy material; The thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 50 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(91) The preparation method of the high-gain solar-blind ultraviolet photodetector based on the (GaY).sub.2O.sub.3 ternary alloy in this embodiment is basically the same as the preparation method of the solar-blind ultraviolet photodetector based on the (GaLu).sub.2O.sub.3 ternary alloy in Example 1. The only difference is that, the laser ablation target uses (GaY).sub.2O.sub.3 ternary alloy material made in this embodiment.

(92) FIG. 15 is the XRD survey-scan spectrum of (GaY).sub.2O.sub.3 thin film and pure Ga.sub.2O.sub.3 thin film. As shown in the figure, for the (GaY).sub.2O.sub.3 thin film, except for the diffraction peaks of the c-plane sapphire substrate, no other diffraction peaks were found, indicating that this embodiment successfully obtained an amorphous (GaY).sub.2O.sub.3 ternary alloy thin film. FIG. 16 is the I-V curve of the (GaY).sub.2O.sub.3 solar-blind ultraviolet photodetector produced in this example. It can be clearly seen that the I-V curve under illumination is non-linear, indicating that there is a formation of Schottky contact between Au and (GaY).sub.2O.sub.3 film. FIG. 17 is the time-current response curve of the device at 10V bias voltage. It can be seen from the figure that the dark current of this device is very small (˜0.1 pA) at 10 V bias, which is much smaller than the dark current of pure Ga.sub.2O.sub.3-based photodetectors (˜10.6 pA). This is because that the band gap of Y.sub.2O.sub.3 (5.6 eV) is larger than that of Ga.sub.2O.sub.3 (4.9 eV), and the doping of Y.sup.3+ ions can significantly increase the band gap of Ga.sub.2O.sub.3, which makes the dark current of photodetectors based on (GaY).sub.2O.sub.3 with wider band gaps significantly reduced. At the same time, we use the double exponential relaxation equation to fit the curve, and the device relaxation response time τ.sub.d2 is only 0.017 s, which is much shorter than the relaxation response time of the pure Ga.sub.2O.sub.3-based photodetector (τ.sub.d2=0.661 s). This is because that the binding energy between Y.sup.3+ ions and O.sup.2− ions is stronger than that between Ga.sup.3+ ions and O.sup.2− ions, so that the (GaY).sub.2O.sub.3 ternary alloy film has a lower oxygen vacancy concentration than the pure Ga.sub.2O.sub.3 film. The lower concentration of oxygen vacancies leads to fewer trap centers in the film, which results in a significantly faster relaxation response speed of the device. At the same time, unlike pure Ga.sub.2O.sub.3 thin films, there are many dangling bonds and surface state defects in amorphous (GaY).sub.2O.sub.3 films. These defects can be used as carrier recombination centers to promote carrier recombination, so they can greatly reduce the relaxation response time of the photodetector. FIG. 26 is the wavelength-responsivity curve of the (GaY).sub.2O.sub.3 based photodetector and the comparative example 1 pure Ga.sub.2O.sub.3 based photodetector of this embodiment. Benefiting from the relatively wider band gap of (GaY).sub.2O.sub.3, the peak response wavelength of (GaY).sub.2O.sub.3 based photodetector (245 nm), is shorter than that of the pure Ga.sub.2O.sub.3 based photodetector (255 nm). In addition, the (GaY).sub.2O.sub.3-based photodetector prepared in this example has a peak responsivity (R.sub.max=691.3 A/W), a detection rate (D*=1.37×10.sup.16), and a light-dark current ratio (I.sub.light/I.sub.dark=1.1×10.sup.7), much higher than the peak responsivity (R.sub.max=20.9 A/W), detection rate (D*=8.04×10.sup.13), and light-dark current ratio (I.sub.light/I.sub.dark=6.9×10.sup.3) of pure Ga.sub.2O.sub.3-based photodetectors.

(93) In summary, (GaY).sub.2O.sub.3-based photodetectors have lower dark current, significantly faster recovery speed, shorter peak response wavelength, and significantly increased peak responsivity and detection rate than pure Ga.sub.2O.sub.3-based photodetectors, showing a more sensitive and faster detection capability for solar-blind ultraviolet light.

Example 10

(94) A (GaY).sub.2O.sub.3 ternary alloy material in this embodiment is made of Ga.sub.2O.sub.3 powder and Y.sub.2O.sub.3 powder with a molar ratio of 95:5 by solid phase sintering. The specific method is as follows:

(95) 1.1 According to the molar ratio of Ga.sub.2O.sub.3:Y.sub.2O.sub.3=95:5, weigh 9.403 g Ga.sub.2O.sub.3 powder and 0.596 g Y.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then put it in a ball mill tank of the planetary ball mill (ball milling media are zirconia ceramic balls), ball mill for 4 h to obtain mixed powder;

(96) 1.2 The obtained mixed powder is made into the (GaY).sub.2O.sub.3 ternary alloy material by using the same processing steps of step 1.2 and step 1.3 of Example 1 in sequence.

(97) The (GaY).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaY).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes from bottom to top, where: The active layer is an amorphous (GaY).sub.2O.sub.3 thin film, the amorphous (GaY).sub.2O.sub.3 thin film is deposited using the (GaY).sub.2O.sub.3 ternary alloy material; the thickness of the c-plane sapphire substrate is 0.43 mm, and the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 55 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(98) The solar-blind ultraviolet photodetector based on (GaY).sub.2O.sub.3 ternary alloy described in this embodiment is prepared by the same preparation method as the solar-blind ultraviolet photodetector based on (GaY).sub.2O.sub.3 ternary alloy in Example 9.

(99) A voltage of 10 V was applied between the electrodes of the device prepared in this example while the surface of the sample was irradiated with monochromatic light to perform photoelectric performance tests. The results show that the dark current of the device is very low (I.sub.dark=1.5 pA), the response speed is faster, and the device's recovery response time τ.sub.d2 is only 0.037 s, which shows a good detection ability for solar-blind ultraviolet light. The test results are shown in FIG. 18.

Example 11

(100) A (GaY).sub.2O.sub.3 ternary alloy material in this embodiment is made of Ga.sub.2O.sub.3 powder and Y.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is the same as that of Example 9.

(101) The (GaY).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaY).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Al electrodes from bottom to top, where: The active layer is an amorphous (GaY).sub.2O.sub.3 ternary alloy film, and the amorphous (GaY).sub.2O.sub.3 ternary alloy film is deposited using the (GaY).sub.2O.sub.3 ternary alloy material; the thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 300 nm, the thickness of the parallel metal Al electrode is 30 nm, and the spacing of the parallel metal Al electrodes is 50 μm.

(102) The solar-blind photodetector based on (GaY).sub.2O.sub.3 ternary alloy in this embodiment is prepared by the same preparation method as the solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 3, with the only difference: in this embodiment the laser ablation target material used is (GaY).sub.2O.sub.3 ternary alloy material made in this embodiment, and the evaporation source in this embodiment is metal Al, and the amount is 0.10 g.

Example 12

(103) A (GaY).sub.2O.sub.3 ternary alloy material in this embodiment is made of Ga.sub.2O.sub.3 powder and Y.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The specific method is the same as that of Example 9.

(104) The (GaY).sub.2O.sub.3 ternary alloy material described in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind photodetector based on (GaY).sub.2O.sub.3 ternary alloy in this embodiment includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Pt electrodes from bottom to top, where: The active layer is an amorphous (GaY).sub.2O.sub.3 ternary alloy film, the amorphous (GaY).sub.2O.sub.3 ternary alloy film is deposited using the (GaY).sub.2O.sub.3 ternary alloy material; the thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 200 nm, the thickness of the parallel metal Pt electrode is 70 nm, and the spacing of the parallel metal Pt electrodes is 100 μm.

(105) The preparation method of the solar-blind ultraviolet photodetector based on (GaY).sub.2O.sub.3 ternary alloy in this embodiment is basically the same as the preparation method of the solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in Example 4, with the only difference: in this embodiment the laser ablation target material used is (GaY).sub.2O.sub.3 ternary alloy material made in this embodiment, and the evaporation source in this embodiment is Pt, and the amount is 0.25 g.

Example 13

(106) A (GaLu).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Lu.sub.2O.sub.3 powder with a molar ratio of 95:5 by solid phase sintering. The specific method is as follows:

(107) 1.1 According to the molar ratio of Ga.sub.2O.sub.3:Lu.sub.2O.sub.3=95:5, weigh 8.995 g Ga.sub.2O.sub.3 powder and 1.005 g Lu.sub.2O.sub.3 powder, after mixing, add 15 g of deionized water, and then put it in a ball mill tank in a planetary ball mill (the ball milling media are zirconia ceramic balls), ball milling for 4 hours to obtain mixed powder;

(108) 1.2 Place the mixed powder in a vacuum drying oven, vacuum dry at 110° C. for 12 h, take it out and cool it to room temperature naturally, sieve out the zirconia balls, add 1 g of deionized water, use a grinding bowl to grind it evenly, and then press it using a tablet press into a wafer with a diameter of 27.5 mm and a thickness of 2 mm at a pressure of 8 MPa;

(109) 1.3 Place the wafer into a crucible in a vacuum tube furnace, and put a powder (15.0000 g) of the same composition around it. The tube furnace was heated to 1300° C. and kept for 3 hours, and then naturally cooled to room temperature to obtain the (GaLu).sub.2O.sub.3 ternary alloy material.

(110) The (GaLu).sub.2O.sub.3 ternary alloy material described above in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal electrodes in sequence from bottom to top, where: The active layer is an amorphous (GaLu).sub.2O.sub.3 ternary alloy film, the amorphous (GaLu).sub.2O.sub.3 ternary alloy film is deposited using the (GaLu).sub.2O.sub.3 ternary alloy material; the parallel metal electrode material is Au, the thickness of the substrate is 0.43 mm, the thickness of the active layer is 120 nm, the thickness of the parallel metal Au electrode is 50 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(111) The solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment is prepared by the following method, including the following steps:

(112) 2.1 Use the (GaLu).sub.2O.sub.3 ternary alloy material prepared in step 1.3 as a laser ablation target, and put it into a vacuum chamber together with an m-plane sapphire substrate that has been ultrasonically cleaned with acetone, absolute ethanol, and deionized water for 15 minutes sequentially. And the chamber is evacuated to 10.sup.−4 Pa;

(113) 2.2 After the substrate temperature reaches 700° C., oxygen is introduced to maintain the gas pressure at 6 Pa during the entire film deposition process; then the substrate and the target are set to rotate, the laser output energy and pulse repetition frequency are set to 300 mJ/pulse and 5 Hz, respectively, and then turn on the laser and start depositing (GaLu).sub.2O.sub.3 ternary alloy thin film. After 30 minutes of deposition, the oxygen and heating were turned off, and finally the sample was naturally cooled to room temperature in a vacuum and taken out;

(114) 2.3 Place the obtained (GaLu).sub.2O.sub.3 ternary alloy film on the mask plate and install it in the vacuum chamber of the vacuum evaporation machine, then install the tungsten boat and feed it with the evaporation source-metal Au 0.2 g, close the vacuum chamber and turn on the mechanical pump, fore-stage valve, molecular pump, and pump the chamber to below 10.sup.−4 Pa. Then turn on the evaporation power, slowly increase the current until the metal Au melts, and then keep the current constant and open the baffle to start evaporation. After the metal Au is evaporated, the current is slowly reduced, the evaporation source is closed, the molecular pump, the fore-stage valve, and the mechanical pump are turned off, and then the air valve is opened to flow air into the chamber. Finally the solar-blind photodetector based on the amorphous (GaLu).sub.2O.sub.3 film is obtained.

(115) FIG. 19 is an XRD survey-scan spectrum of an amorphous (GaLu).sub.2O.sub.3 ternary alloy thin film prepared in this example. As shown in the figure, except for the diffraction peak of the m-plane sapphire substrate, there are no other diffraction peaks, indicating that in this embodiment an amorphous (GaLu).sub.2O.sub.3 thin film was successfully obtained. FIG. 20 is the I-V curve of a solar-blind UV photodetector based on (GaLu).sub.2O.sub.3 ternary alloy produced in this example, it can be clearly seen that the I-V curve under illumination is nonlinear, indicating that the Schottky contact is formed between the Au and amorphous (GaLu).sub.2O.sub.3 ternary alloy film. FIG. 21 shows the time-current response curve of the device at 10 V bias voltage. It can be seen from FIG. 21 that under a 10V bias voltage, the dark current of the device is extremely low (I.sub.dark=0.4 pA). This is because Lu.sub.2O.sub.3 and Ga.sub.2O.sub.3 form a (GaLu).sub.2O.sub.3 alloy, that is, the incorporation of Lu.sup.3+ widens the band gap of Ga.sub.2O.sub.3, so that the dark current of (GaLu).sub.2O.sub.3-based photodetectors with a wider band gap is significantly reduced. At the same time, we use the double exponential relaxation equation I=I.sub.0+Ae.sup.−t/τ.sup.1+Be.sup.−t/τ.sup.2 to fit the curve, and the device recovery response time τ.sub.d2 is only 0.020 s, which is much shorter than the recovery response time of the pure Ga.sub.2O.sub.3-based photodetector (τ.sub.d2=0.661 s). This is because the lattice mismatch between the m-plane sapphire and Ga.sub.2O.sub.3 is large, so an amorphous (GaLu).sub.2O.sub.3 thin film is grown on the m-plane sapphire. Since the bond energy of the Lu—O bond is greater than the Ga—O bond, the introduction of Lu will greatly reduce the oxygen vacancy in the film and speed up the response speed of the device; at the same time, there are many dangling bonds and surface states in the amorphous (GaLu).sub.2O.sub.3 film, which serve as recombination centers to further accelerate the response speed of the device. And from the wavelength-responsivity curve of the solar-blind ultraviolet photodetector based on the amorphous (GaLu).sub.2O.sub.3 film prepared in this example, it can be seen that the peak response wavelength (235 nm) of the amorphous (GaLu).sub.2O.sub.3-based photodetector is blue shifted compared with the photodetector in Comparative Example 1 due to the relatively wider band gap of (GaLu).sub.2O.sub.3. In summary, compared with the pure Ga.sub.2O.sub.3 thin film-based photodetector of Comparative Example 1, the amorphous (GaLu).sub.2O.sub.3-based photodetector has a lower dark current, significantly faster recovery speed, a shorter peak response wavelength, and a larger photo-dark current ratio (I.sub.light/I.sub.dark=7.34×10.sup.4) and higher detection rate (D*=8×10.sup.14), showing a more sensitive and faster detection ability for solar-blind ultraviolet light.

Example 14

(116) A (GaLu).sub.2O.sub.3 ternary alloy material of this embodiment is made of Ga.sub.2O.sub.3 powder and Lu.sub.2O.sub.3 powder with a molar ratio of 70:30 by solid phase sintering. The method is the same as that of Example 1.

(117) The (GaLu).sub.2O.sub.3 ternary alloy material described above in this embodiment is used to prepare a solar-blind ultraviolet photodetector. A solar-blind ultraviolet photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment includes an m-plane sapphire substrate, an active layer, and a pair of parallel metal electrodes in sequence from bottom to top, where: The active layer is an amorphous (GaLu).sub.2O.sub.3 ternary alloy film. The amorphous (GaLu).sub.2O.sub.3 ternary alloy film is deposited using the (GaLu).sub.2O.sub.3 ternary alloy material; the parallel metal electrode material is Al, the thickness of the substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Al electrode is 50 nm, and the spacing of the parallel metal Al electrodes is 50 μm.

(118) The solar-blind photodetector based on (GaLu).sub.2O.sub.3 ternary alloy in this embodiment is prepared by the following method, including the following steps:

(119) 2.1 Using the (GaLu).sub.2O.sub.3 ternary alloy material described above as a laser ablation target in this embodiment, it was loaded into a vacuum chamber together with a sapphire substrate that was ultrasonically cleaned with acetone, absolute ethanol and deionized water, etc. for 15 minutes, and pump the chamber down to 10.sup.−4 Pa;

(120) 2.2 After the substrate temperature reaches 500° C., oxygen is introduced to maintain the gas pressure at 1 Pa during the entire film deposition process; then the substrate and the target are set to rotate, the laser output energy and pulse repetition frequency are set to 300 mJ/pulse and 5 Hz, respectively, and then the laser is turned on to start depositing (GaLu).sub.2O.sub.3 ternary alloy thin film. After 30 minutes of deposition, the oxygen and heating were turned off, and finally the sample was naturally cooled to room temperature in a vacuum and taken out;

(121) 2.3 Place the obtained (GaLu).sub.2O.sub.3 ternary alloy film on the mask plate and install it into the vacuum chamber of the vacuum evaporation machine, then install the tungsten boat and feed it with the evaporation source-metal Al 0.10 g, close the vacuum chamber, and start the mechanical pump, fore-stage valve, molecular pump, and pump the chamber to below 10.sup.−4 Pa. Then turn on the evaporation power, slowly increase the current until the metal Al melts, and then keep the current constant and open the baffle to start evaporation. After the evaporation of the metal Al is completed, the current is slowly reduced, the evaporation source is closed, the molecular pump, the fore-stage valve, and the mechanical pump are turned off, and then the air valve is opened to flow air into the chamber. Finally the solar-blind ultraviolet photodetector based on the (GaLu).sub.2O.sub.3 ternary alloy is obtained.

(122) A voltage of 7 V was applied between the electrodes of the device prepared in this example while the surface of the sample was irradiated with monochromatic light to perform photoelectric performance tests. The test results show that the dark current of this device is extremely low (I.sub.dark=0.2 pA), and the ratio of light to dark current is 9000. It can be seen that the device also exhibits better detection performance at lower bias voltages. The test results are shown in FIG. 22.

Comparative Example 1

(123) A solar-blind UV photodetector based on Ga.sub.2O.sub.3 thin film of the present comparative example includes a c-plane sapphire substrate, an active layer, and a pair of parallel metal Au electrodes in sequence from bottom to top, wherein: the active layer is a Ga.sub.2O.sub.3 film, the thickness of the c-plane sapphire substrate is 0.43 mm, the thickness of the active layer is 150 nm, the thickness of the parallel metal Au electrode is 55 nm, and the spacing of the parallel metal Au electrodes is 10 μm.

(124) The solar-blind UV photodetector based on Ga.sub.2O.sub.3 film mentioned above in this comparative example is prepared by the following method, including the following steps:

(125) Step 1: Preparation of Ga.sub.2O.sub.3 Ceramic Target by Solid-Phase Sintering

(126) 1.1 Weigh 10 g of Ga.sub.2O.sub.3 powder, add 15 g of deionized water, and then put it in a ball milling tank (ball milling media are zirconia ceramic balls) in a planetary ball mill, and ball mill for 4 h to obtain a uniformly dispersed powder;

(127) 1.2 Using the same processing steps of step 1.2 and step 1.3 of Example 1, the obtained powder is made into the Ga.sub.2O.sub.3 ceramic target.

(128) Step 2 Use Ga.sub.2O.sub.3 Ceramic Target to Prepare Solar-Blind UV Photodetector

(129) The treatment process of step 2 of this comparative example is basically the same as that of step 2 of example 1, except that the laser ablation target in this comparative example uses Ga.sub.2O.sub.3 ceramics.

(130) A voltage of 10 V was applied between the electrodes of the device prepared in this comparative example while the surface of the sample was irradiated with monochromatic light for photoelectric performance testing. The results show that the dark current of the device is I.sub.dark=10.6 pA, the relaxation response times τ.sub.r2 and τ.sub.d2 are 0.579 s and 0.661 s, respectively, and the peak response Rmax=20.9 A/W. The test results are shown in FIG. 23, FIG. 24, and FIG. 26, respectively. It can be seen that the dark current of the device made in this comparative example is obviously higher than that of the (GaMe).sub.2O.sub.3-based photodetector, and the response speed is slower. Comparing with this comparative example, the (GaMe).sub.2O.sub.3-based photodetector of the present invention has significantly better solar-blind ultraviolet light detection capability.

(131) One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.

(132) It will thus be seen that the objects of the present invention have been fully and effectively accomplished. Its embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.