Method for preparing gallium oxide nanowire without catalyst

Abstract

The invention discloses a method for preparing gallium oxide nanowires without a catalyst, and belongs to the field of preparation and growth methods of inorganic compound semiconductor materials. According to the method, a plasma enhanced chemical vapor deposition system is innovatively adopted, metal gallium serves as a gallium source, no catalyst is needed, and in a uniformly-heated quartz tube, the growth conditions are as follows: the temperature is 900-950 DEG C, the gas flow (Ar gas is 30-20 sccm, and oxygen is 10 sccm) and the radio frequency power is 60-100 W. The gallium oxide nanowire with high purity and high crystallinity is directly and spontaneously grown on an atomic-scale polished silicon wafer substrate. According to the method, the pollution of the catalyst is avoided, the cost is reduced, the aspect ratio and the crystallization quality of the nanowire are improved, and the growth of the nanowire with the diameter of nanoscale and the length of millimeter level is realized. The prepared gallium oxide nanowire shows solar-blind photoelectric detection performance, and the maximum photocurrent can reach 0.501 microamperes when 10V bias voltage is applied.

Description

Technical Field

[0001] The invention relates to a method for preparing gallium oxide nanowires without a catalyst, belongs to the field of inorganic compound semiconductor material preparation and growth methods, and particularly relates to the photoelectric properties of the material. Background Art

[0002] In the exploration of new semiconductor materials and their nanostructure preparation technology, the research on the catalyst-free preparation of gallium oxide (Ga2O3) nanowires has received increasing attention. One-dimensional (1D) nanostructures, especially nanowires, have shown great application potential in high-performance sensors and future energy storage and conversion devices due to their unique electrical, optical and thermal properties. As a representative of ultra-wide bandgap semiconductor materials, gallium oxide has broad application prospects in high-voltage power electronic devices, solar-blind ultraviolet detectors and high-temperature gas sensors due to its high breakdown electric field, high thermal conductivity and good chemical stability.

[0003] Traditionally, the preparation of gallium oxide nanowires mostly uses catalyst-assisted methods, such as metal particle catalysis. Although these methods can achieve the growth of nanowires, the catalyst residue may affect the purity and performance of the material, and the subsequent processing steps are complicated. In addition, the template method has also been used to prepare orderly arranged gallium oxide nanowires, but the process is cumbersome and costly, and the template removal process may damage the nanowire structure.

[0004] In view of the above challenges, catalyst-free direct growth technology has become a research hotspot. This technology aims to achieve the spontaneous growth of gallium oxide nanowires without the intervention of additional catalysts by optimizing growth conditions such as temperature, gas flow rate, precursor type, etc. At present, commonly used catalyst-free preparation methods include physical vapor deposition, pulsed laser deposition, etc. However, these methods still have limitations to varying degrees in growth rate, nanowire morphology control and crystal quality.

[0005] Our team is committed to developing an innovative catalyst-free method for preparing gallium oxide nanowires, using a self-developed plasma enhanced chemical vapor deposition system. It is able to achieve high-speed, high-quality growth of gallium oxide nanowires without catalysts, while also having an ultra-high nanowire aspect ratio. This method not only simplifies the preparation process and reduces costs, but is also expected to open up new avenues for the application of gallium oxide nanomaterials in high-performance optoelectronic devices. Summary of the invention

[0006] The purpose of the present invention is to provide an efficient, catalyst-free method for preparing gallium oxide nanowires, which utilizes a plasma enhanced chemical vapor deposition system, uses metal gallium as a gallium source, nitrogen as a nitrogen source, and uses an atomically polished silicon wafer as a growth substrate in a uniformly heated quartz tube. The method directly generates high-purity, high-crystallinity gallium nitride nanowires on the substrate through an inverted growth method, thereby simplifying the process, reducing costs, and avoiding catalyst contamination, thereby providing new possibilities for the widespread application of gallium oxide materials.

[0007] The present invention provides a green catalyst-free method for preparing gallium oxide nanowires, which is characterized by comprising the following steps:

[0008] Step 1: The growth substrate needs to be purged and etched in an Ar plasma environment at a pressure of 20-30 Pa and a power of 60-100 W for 10-180 minutes.

[0009] Step 2: Place metal gallium at the center of a corundum crucible, and invert the growth surface of the substrate material processed in step 1 onto the corundum crucible, and then place the entire crucible at the center of the heating position of the reaction chamber of the plasma enhanced chemical vapor deposition system.

[0010] Step 3: Introduce Ar gas at a flow rate of 5 sccm-200 sccm through the system, exhaust other impurities in the system, and raise the temperature to 900-950°C at a rate of 5°C / min under the protection of Ar gas.

[0011] Step 4: After step 3, the Ar gas flow rate is increased to 10-100 sccm, the oxygen flow rate is 5-50 sccm, the RF power is adjusted to 60-120 W, and the reaction time is 10-60 minutes. A linear product is generated, namely gallium oxide nanowires.

[0012] Furthermore, the substrate required for the growth is a sheet material with a melting point greater than 1000°C.

[0013] Furthermore, in step 4, the flow ratio of argon gas to oxygen gas is between 1:1 and 20:1.

[0014] Furthermore, the nanowire product in step 4 is gallium oxide nanowire with a diameter of 20-500nm and a length of 10μm-800μm.

[0015] Plasma purge etching can cause etching on the substrate surface, and the substrate will inevitably form an oxide layer on the surface during normal storage. Etching will randomly etch away the atoms on the surface, especially oxygen atoms. During the growth process, Ga first combines with O to form Ga 2 O 3Particles, the O in the particles will combine with vacancies to form original sites, and the particles on the original sites will act as self-catalytic grains to grow nanowires. Electrodes are prepared on the surface of the nanowires, and the method is the same as that of the patent "CN115000244A" to obtain the corresponding ultraviolet detector.

[0016] The present invention has the following advantages and benefits:

[0017] (1) Gallium oxide nanowires avoid the use of catalysts, effectively reducing the preparation cost, improving the crystallinity of the nanowires, and avoiding the contamination of the nanowires by catalyst elements.

[0018] (2) The grown nanowires have an ultra-high aspect ratio, with a diameter at the nanometer scale and a length up to the millimeter level.

[0019] (3) The UV sensor prepared using sub-nanowires has a good response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Top view SEM image of gallium oxide nanowires prepared in Example 1

[0021] Figure 2 Cross-sectional SEM image of gallium oxide nanowires prepared in Example 1

[0022] Figure 3 A top view SEM image of the gallium oxide nanowires prepared in Example 2

[0023] Figure 4 Cross-sectional SEM image of gallium oxide nanowires prepared in Example 2

[0024] Figure 5 Top view SEM image of gallium oxide nanowires prepared in Example 3

[0025] Figure 6 Cross-sectional SEM image of gallium oxide nanowires prepared in Example 3

[0026] Figure 7 XRD patterns of gallium oxide nanowires prepared in Example 1-3

[0027] Figure 8 Ultraviolet response spectrum of gallium oxide nanowires prepared in Example 1

[0028] Fig. 9 UV response spectrum of gallium oxide nanowires prepared in Example 2

[0029] Fig.10 UV response spectrum of gallium oxide nanowires prepared in Example 3 DETAILED DESCRIPTION

[0030] In order to clearly describe the device preparation method described in the examples of the present invention and the outstanding advantages obtained, the present invention is specifically described below in conjunction with the drawings and examples, and the implementation examples described below are part of the examples of the present invention, not all of the implementation examples.

[0031] Implementation Example 1

[0032] Step 1: Cut the purchased 4-inch polycrystalline silicon wafer into 1×2cm small pieces, use acetone, toluene and alcohol for ultrasonic cleaning for 15 minutes respectively, and use Ar plasma for 30 minutes, with a plasma pressure of 23Pa and a power of 60W. After the treatment, place it in anhydrous ethanol for later use.

[0033] Step 2: Weigh 0.05g of gallium metal and place it in the center of a corundum crucible. Take out the polycrystalline silicon wafer and blow it dry with nitrogen. Place the polished surface upside down on the corundum crucible and place the whole in the center of the heating position of the reaction chamber of the plasma enhanced chemical vapor deposition system.

[0034] Step 3: Ar gas at a flow rate of 30 sccm was introduced into the entire system to exhaust other gases in the system, and the temperature was raised to 900°C at a rate of 5°C / min under the protection of Ar gas.

[0035] Step 4: After step 3, reduce the Ar gas flow rate to 20 sccm and introduce 5 sccm of oxygen. When the gas pressure is constant at 25 Pa, turn on the RF switch and adjust the RF power to 60 W. The reaction time is controlled at 30 min. After the growth is completed, gallium oxide nanowires are obtained. The top view of the nanowire is shown in the attached figure. Figure 1 As shown, the cross-sectional view is shown in the attached Figure 2 As shown, it can be seen that the diameter of the nanowire is 0.5-1μm and the length is 5-20μm. The corresponding XRD test graph is shown in the attached Figure 7 shown.

[0036] Step 5: Prepare the electrode by sputtering the surface of the grown gallium oxide nanowire film at 2.08 mW / cm 2 The detector was aged by irradiating with 254nm ultraviolet light for 10 hours. The radiation value was 20.8mWh. After the aging process was completed, the photoelectric performance test was carried out. The light intensity and wavelength remained unchanged. A 10V bias voltage was applied to both ends of the electrode. Figure 8 As shown, the photocurrent is 0.195μA at this time.

[0037] Implementation Example 2

[0038] Step 1: Cut the purchased 4-inch single crystal silicon wafer into 1×2cm small pieces, use acetone, toluene and alcohol for ultrasonic cleaning for 15 minutes respectively, and use Ar plasma for 100 minutes, with a plasma pressure of 25Pa and a power of 100W. After the treatment, place it in anhydrous ethanol for standby use.

[0039] Step 2: Weigh 0.05g of gallium metal and place it in the center of the corundum crucible. Take out the polycrystalline silicon wafer and blow it dry with nitrogen. Place the polished surface upside down on the corundum crucible and place the whole at the center of the heating position of the plasma enhanced chemical vapor deposition system reaction chamber.

[0040] Step 3: Ar gas with a flow rate of 100 sccm was introduced into the entire system to exhaust other gases in the system, and the temperature was raised to 925°C at a rate of 5°C / min under the protection of Ar gas.

[0041] Step 4: After step 3, reduce the Ar gas flow rate to 50 sccm and introduce 50 sccm of oxygen. When the gas pressure is constant at 20 Pa, turn on the RF switch and adjust the RF power to 100 W. The reaction time is controlled at 30 min. After the growth is completed, gallium oxide nanowires are obtained. The top view of the nanowire is shown in the attached figure. Figure 3 As shown, the cross-sectional view is shown in the attached Figure 4 As shown, it can be seen that the diameter of the nanowire is 0.1-1μm and the length is 10-100μm. The corresponding XRD test diagram is shown in the attached Figure 7 shown.

[0042] Step 5: Prepare the electrode by sputtering the surface of the grown gallium oxide nanowire film at 2.08 mW / cm 2 The detector was aged by irradiating with 365nm ultraviolet light for 20 hours. The radiation value was 41.6mWh. After the aging process was completed, the photoelectric performance test was carried out. The light intensity and wavelength remained unchanged. A 10V bias voltage was applied to both ends of the electrode. Fig. 9 As shown, the photocurrent is 0.233μA at this time.

[0043] Implementation Example 3

[0044] Step 1: Cut the purchased 4-inch single crystal silicon wafer into 1×2cm small pieces, use acetone, toluene and alcohol for ultrasonic cleaning for 15 minutes respectively, and use Ar plasma for 180 minutes, with a plasma pressure of 30Pa and a power of 100W. After the treatment, place it in anhydrous ethanol for standby use.

[0045] Step 2: Weigh 0.05g of gallium metal and place it in the center of the corundum crucible. Take out the polycrystalline silicon wafer and blow it dry with nitrogen. Place the polished surface upside down on the corundum crucible and place the whole at the center of the heating position of the plasma enhanced chemical vapor deposition system reaction chamber.

[0046] Step 3: Ar gas at a flow rate of 200 sccm was introduced into the entire system to exhaust other gases in the system, and the temperature was raised to 950°C at a rate of 5°C / min under the protection of Ar gas.

[0047] Step 4: After step 3, reduce the Ar gas flow rate to 100 sccm and introduce 10 sccm of oxygen. When the gas pressure is constant at 30 Pa, turn on the RF switch and adjust the RF power to 120 W. The reaction time is controlled at 30 min. After the growth is completed, gallium oxide nanowires are obtained. The top view of the nanowire is shown in the attached figure. Figure 3 As shown, the cross-sectional view is shown in the attached Figure 4 As shown, it can be seen that the diameter of the nanowire is 0.1-1μm and the length is 100-800μm. The corresponding XRD test diagram is shown in the attached Figure 7 shown.

[0048] Step 5: Prepare the electrode by sputtering the surface of the grown gallium oxide nanowire film at 8mW / cm 2 The detector was aged by irradiating with 365nm ultraviolet light for 10 hours. The radiation value was 80mWh. After the aging process was completed, the photoelectric performance test was carried out. The light intensity and wavelength remained unchanged. A 10V bias voltage was applied to both ends of the electrode. Fig.10 As shown, the photocurrent is 0.501μA at this time.

[0049] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by anyone familiar with the technology within the technical scope disclosed by the present invention should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing gallium oxide nanowires without a catalyst, characterized in that The following steps are involved: Step 1: The growth substrate needs to be purged and etched in an Ar plasma environment at a pressure of 20-30 Pa and a power of 60-100 W for 10-180 minutes; Step 2: placing metal gallium at the center of a corundum crucible, and inverting the growth surface of the substrate material processed in step 1 onto the corundum crucible, and then placing the crucible as a whole at the center of the heating position of the reaction chamber of the plasma enhanced chemical vapor deposition system; Step 3: introduce Ar gas at a flow rate of 5 sccm-200 sccm through the system, exhaust other impurities in the system, and heat up to 900-950°C at a rate of 5°C / min under the protection of Ar gas; Step 4: The Ar gas flow rate is changed to 10-100 sccm, the oxygen flow rate is 5-50 sccm, the RF power is adjusted to 60-120 W, and the reaction time is 10-60 minutes; a linear product, i.e., gallium oxide nanowires, is generated.

2. The method according to claim 1, characterized in that: The substrate required for growth is a sheet material with a melting point greater than 1000°C.

3. The method according to claim 1, characterized in that: In step 4, the flow ratio of argon gas to oxygen gas is between 1:1 and 20:

1.

4. The method according to claim 1, characterized in that: In step 4, the diameter of the gallium oxide nanowire is 20-1000 nm and the length is 10 μm-800 μm.

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