A method for preparing a large-size GaOCl single crystal by a pressure-assisted sol-gel method and application thereof

Abstract

The application discloses a method for preparing large-size GaOCl monocrystals by pressure-assisted sol-gel method and application, and belongs to the field of material science, which significantly optimizes the kinetics of GaOCl growth by constructing a dynamic sealing high-pressure environment. The GaOCl gel precursor is heated in a reaction furnace with a counterweight device to prepare large-size block GaOCl monocrystals. So far, this technology has not been reported, and the application is the first to realize the technology. The application is mainly based on the characteristics of the high-pressure environment under the dynamic sealing state. On the one hand, this environment greatly inhibits the unnecessary loss of gallium components, increases the collision frequency of reaction molecules and diffusion kinetics, and on the other hand, when the internal gas pressure exceeds the gravity of the counterweight, the excess waste is discharged, avoiding the product agglomeration problem caused by the residual in the completely closed system. The application has important significance for the performance improvement of two-dimensional field effect transistors in the post-moore era.

Description

Technical Field

[0001] This invention relates to a method for preparing large-size GaOCl single crystals using a "pressure-assisted sol-gel method", belonging to the field of semiconductor materials and crystal growth technology. Background Technology

[0002] With the continuous development of integrated circuit technology, transistor performance improvements have long followed the miniaturization path driven by Moore's Law. However, as device feature sizes have entered the nanoscale and even sub-nanometer scale, traditional silicon-based transistors have gradually faced a series of physical limitations, including intensified short-channel effects, decreased gate control capabilities, and significantly increased static power consumption. To continue the performance improvement path, device structures have evolved from traditional planar structures to three-dimensional structures. For example, fin field-effect transistors and fully enclosed gate transistors have enhanced the gate's ability to control the channel's electric field to some extent. However, with the increasing complexity of device structures and the rising manufacturing costs, relying solely on structural optimization is no longer sufficient to meet the future development needs of high-performance, low-power devices.

[0003] Against this backdrop, technological approaches based on novel semiconductor materials have gradually become a focus of international research. Among them, two-dimensional semiconductor materials, represented by molybdenum disulfide, are considered important candidate materials for breaking through the physical limits of traditional silicon-based devices due to their atomic-level thickness, excellent interfacial properties, and good electrostatic control capabilities. However, existing two-dimensional material systems still face challenges such as difficulty in preparing large-area, high-quality single crystals, insufficient environmental stability, and poor compatibility with existing process systems, which limit their engineering applications.

[0004] To address the aforementioned problems, this invention proposes a method for preparing large-size GaOCl single crystals using a pressure-assisted sol-gel method. GaOCl belongs to a novel oxyhalide semiconductor system with unique crystal structure characteristics. Its chemical bonding exhibits both ionic and covalent bonds, displaying weak interlayer interactions and thus possessing the potential to evolve into lower-dimensional structures. This method can be applied to novel transistor devices, deep-ultraviolet photodetectors, and high-stability electronic devices. This invention provides a new material foundation and technological path for expanding two-dimensional semiconductor material systems and overcoming the performance bottlenecks of traditional transistors. Summary of the Invention

[0005] The technical problem addressed by this invention is to overcome the difficulties in preparing large-size, high-quality single crystals of existing two-dimensional semiconductor materials, and the limitations of existing oxide or chalcogenide semiconductor materials in terms of structural tunability and low-dimensionality potential. This invention provides a highly controllable method for preparing GaOCl materials suitable for large-size single crystal growth. Currently, there is no effective single-crystal growth process for GaOCl materials in the prior art, particularly in terms of achieving optimal crystal size, crystal quality, and structural uniformity.

[0006] This invention proposes a pressure-assisted sol-gel method for preparing large-size GaOCl single crystals. GaOCl belongs to a novel oxyhalide semiconductor system with unique crystal structure characteristics. Its chemical bonding exhibits both ionic and covalent bonds, displaying weak interlayer interactions and thus possessing the potential to evolve into lower-dimensional structures. This method can be applied to novel transistor devices, deep-ultraviolet photodetectors, and high-stability electronic devices. This invention provides a new material basis and technological path for overcoming the performance bottlenecks of traditional transistors, promoting the development of the two-dimensional semiconductor field.

[0007] To solve the above-mentioned technical problems, the technical solution proposed in this invention is: a method for preparing large-size GaOCl single crystals using a pressure-assisted sol-gel method, comprising the following steps:

[0008] S1: Place high-purity gallium oxide (Ga2O3) for laboratory use in excess concentrated hydrochloric acid (HCl) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0009] S2: Take a certain amount of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it, finally obtaining a semi-transparent gel-like precursor with high viscosity.

[0010] S3: Place a weight of a specific mass on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device.

[0011] S4: Take the semi-transparent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize.

[0012] S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

[0013] In step S2, the glass container is an open container that is heated in an air atmosphere.

[0014] Preferably, it includes the following steps:

[0015] S1: Place high-purity gallium oxide (Ga2O3, purity 99.99%) for laboratory use in excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0016] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0017] S3: Place a weight of a specific mass on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device.

[0018] S4: Take the semi-transparent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize.

[0019] S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

[0020] Preferably, it includes the following steps:

[0021] S1: Place high-purity gallium oxide (Ga2O3, purity 99.99%) for laboratory use in excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0022] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃ and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0023] S3: Place a weight of a specific mass on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device.

[0024] S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250 degrees Celsius, and the heating time is 2.5 days.

[0025] S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

[0026] Preferably, it includes the following steps:

[0027] S1: Place high-purity gallium oxide (Ga2O3, purity 99.99%) for laboratory use in excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0028] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃ and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0029] S3: Place a 200g weight on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device.

[0030] S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250℃ and the heating time is 2.5 days.

[0031] S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

[0032] Preferably, it includes the following steps:

[0033] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0034] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃ and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0035] S3: Place a 200g weight on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device.

[0036] S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250℃ and the heating time is 2.5 days.

[0037] S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

[0038] The application of the pressure-assisted sol-gel method for preparing large-size GaOCl single crystals described above is in the fields of transistor devices, deep ultraviolet photodetectors, or high-stability electronic devices.

[0039] Beneficial effects:

[0040] This invention proposes a pressure-assisted sol-gel method for preparing large-size GaOCl single crystals. GaOCl belongs to a novel oxyhalide semiconductor system with unique crystal structure characteristics. Its chemical bonding exhibits both ionic and covalent bonds, displaying weak interlayer interactions and thus possessing the potential to evolve into lower-dimensional structures. This method can be applied to novel transistor devices, deep-ultraviolet photodetectors, and high-stability electronic devices. This invention provides a new material foundation and technological path for expanding two-dimensional semiconductor material systems and overcoming the performance bottlenecks of traditional transistors.

[0041] The main physical mechanism of this invention is to achieve synergistic regulation of structural evolution and growth kinetics by introducing external pressure during the precursor gel formation and crystal transformation stages. During the sol-gel process, pressure promotes the densification and ordered rearrangement of the precursor network, which is beneficial for improving system homogeneity and reducing defect sources. During the nucleation and growth stages, pressure can, to a certain extent, regulate the nucleation energy barrier and mass transport behavior, thereby increasing the probability of single-crystal nucleation and promoting ordered crystal growth. Simultaneously, the synergistic effect of Ga-O and Ga-Cl bonds in GaOCl gives it a certain degree of structural anisotropy; pressure regulation helps optimize this structural arrangement, thus facilitating the formation of crystal structures with potentially weak interlayer interactions. The combined effect of these mechanisms enables the controllable preparation of high-quality, large-size GaOCl single crystals.

[0042] The source-drain current of the device was measured as a function of different source-drain voltages (V). ds ) and gate-source voltage (V g The changes under these conditions yield the transfer characteristic curve and the output characteristic curve (see...). Figure 11 and Figure 12 ), from the transfer characteristic curve (see Figure 11 It can be seen that the subthreshold swing SS of the device is 100mV / dec, and the on / off ratio reaches 10. 8 This indicates that the material has excellent turn-off capability and low static power consumption, as shown by the output characteristic curve (see...). Figure 12 As can be seen, the curve is a straight line at low leakage voltage, indicating that the device exhibits perfect ohmic contact with low contact resistance. It can be applied to novel transistor devices, deep ultraviolet photodetectors, and high-stability electronic devices. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the covered glass container in Example 1.

[0044] Figure 2 This is a schematic diagram of a reaction furnace with a counterweight device assembled from a covered glass dish and weights in Example 1.

[0045] Figure 3 The well-grown transparent sheet-like GaOCl crystals obtained in Example 1 are shown.

[0046] Figure 4 The images show the surface distribution of the three elements and the electron image of the well-grown transparent sheet-like GaOCl crystal obtained in Example 1.

[0047] Figure 5 The image shows the XRD pattern of the well-grown transparent sheet-like GaOCl crystals obtained in Example 1.

[0048] Figure 6The image shows the absorption spectrum of the well-grown transparent sheet-like GaOCl crystals obtained in Example 1.

[0049] Figure 7 The image shows the SHG intensity of the well-grown transparent sheet-like GaOCl crystal obtained in Example 1 as a function of wavelength, along with its 360-degree optical polarization fitting curve.

[0050] Figure 8 The image shows the Raman spectrum of the well-grown transparent sheet-like GaOCl crystal obtained in Example 1 and its 360-degree optical polarization fitting curve.

[0051] Figure 9 This is a schematic diagram of the bottom-gate field-effect transistor constructed in Example 1.

[0052] Figure 10 This is an image of the bottom-gate field-effect transistor constructed in Example 1 under an optical microscope.

[0053] Figure 11 The figure shows the transfer characteristic curve of the bottom-gate field-effect transistor constructed in Example 1.

[0054] Figure 12 The output characteristic curve of the bottom-gate field-effect transistor constructed in Example 1 is shown.

[0055] Figure 13 This is an image of a test tube in a sealed vacuum environment as described in Example 2.

[0056] Figure 14 This is an image of GaOCl crystals attached to droplets obtained in Example 2.

[0057] Figure 15 This refers to the open container in Example 3.

[0058] Figure 16 This is an image of the GaOCl polycrystalline powder obtained from the reaction in Example 3.

[0059] Figure 17 This is an image of the powder obtained in Example 4 that is not the target product.

[0060] Figure 18 This is an image of the water-containing crystalline product from Example 5.

[0061] Figure 19 This is an image of thick GaOCl nanosheets deposited on the semi-dry gel precursor in Example 6. Detailed Implementation

[0062] The present invention will be further described below with reference to embodiments.

[0063] Example 1:

[0064] A method for preparing large-size GaOCl single crystals using the "pressure-assisted sol-gel method" is described below:

[0065] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, mass purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0066] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃ and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0067] S3: Place the 200g weight in a covered glass dish (see...) Figure 1 Above the lid, a reactor with a counterweight device is formed (see...). Figure 2 ).

[0068] S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250℃ and the heating time is 2.5 days.

[0069] S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor, obtaining well-grown transparent plate-like GaOCl crystals. (See...) Figure 3 ), Figure 3 The crystals appear to be about 5 millimeters in size.

[0070] S6: The GaOCl crystal obtained in S5 was characterized to obtain the surface distribution images of the three elements in the crystal and the electronic images (see...). Figure 4 ), XRD patterns (see Figure 5 ) and absorption spectrum (see appendix) Figure 6 ).

[0071] S7: Take the GaOCl single crystal obtained in S5, measure its material properties, and obtain the graph of SHG intensity as a function of wavelength and its polar coordinate fitting curve (see...). Figure 7 Raman spectra and their polar coordinate fitting curves (see appendix) Figure 8 ).

[0072] S8: By Figure 4 It can be seen that the three elements constituting a GaOCl single crystal are uniformly distributed in the crystal lattice, as shown by XRD (see...). Figure 5 It can be seen that GaOCl single crystals at 2θ = 18.8 ° , 21.6 ° , 25.8 ° 28.8 °33.0 ° , 34.7 ° , 44.2 ° , 48.1 ° 48.7 ° 51.5 ° 52.7 ° 56.3 ° , 59.1 ° A characteristic peak appears at this location, as shown in the absorption spectrum (see...). Figure 6 As can be seen, GaOCl single crystal has an absorption peak at 200 nm, and the absorption value decreases with increasing wavelength thereafter, with a small absorption fluctuation characteristic between 400 and 500 nm.

[0073] S9: By Figure 7 It can be seen that the optimal second harmonic wavelength of GaOCl single crystal is around 530 nanometers, as indicated by the attached... Figure 8 It can be seen that the Raman spectral peaks of GaOCl single crystal are located at 66, 91, 146, 194, and 470 cm⁻¹. -1 .

[0074] S10: Using a mechanical exfoliation method, two-dimensional GaOCl nanosheets were torn from the GaOCl single crystal obtained in S5 under a microscope to form a bottom-gate field-effect transistor as the gate dielectric layer. Figure 9 and Figure 10 As shown, the device uses Bi / Au as the source and drain electrodes and a monolayer of MoS2 as the conductive channel. The entire device is constructed on a silicon substrate.

[0075] S11: The source-drain current of the device was measured as a function of different source-drain voltages (V). ds ) and gate-source voltage (V g The changes under these conditions yield the transfer characteristic curve and the output characteristic curve (see...). Figure 11 and Figure 12 As shown in the transfer characteristic curve (see Appendix 11), the subthreshold swing SS of the device is 100 mV / dec, and the on / off ratio reaches 10. 8 This indicates that the material has excellent turn-off capability and low static power consumption, as shown by the output characteristic curve (see...). Figure 12 As can be seen, the curve is a straight line at low leakage voltage, indicating that the device exhibits perfect ohmic contact with low contact resistance. It can be applied to novel transistor devices, deep ultraviolet photodetectors, and high-stability electronic devices.

[0076] Example 2:

[0077] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0078] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140 degrees Celsius, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0079] S3: Take the translucent, high-viscosity gel precursor prepared in S2, place it in a sealed vacuum tube, and heat it to evaporate and crystallize at 250 degrees Celsius for 2.5 days. (See...) Figure 13 )

[0080] S4: Use tweezers to remove the crystal from the sealed container, obtaining a GaOCl crystal with droplets attached. (See...) Figure 14 )

[0081] By replacing the reaction vessel of the gel precursor with a closed container, the water molecules cannot escape in the closed environment. When the pressure in the system reaches the saturated vapor pressure, the rate of water evaporation is equal to the rate of condensation. During this process, water vapor continuously impacts the surface of the crystal and is re-adsorbed, resulting in the crystal surface being wetted by water, and GaOCl crystal products with droplet attachment are obtained. This product is not conducive to the preparation of two-dimensional nanofilms by mechanical exfoliation, and the outer surface of the crystal is damaged.

[0082] Example 3:

[0083] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0084] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140 degrees Celsius, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0085] S3: Take the translucent, high-viscosity gel precursor prepared in S2 and place it in an open container (see...). Figure 15 In the process of evaporation and crystallization, the heating temperature is 250 degrees Celsius and the heating time is 2.5 days.

[0086] S4: Use tweezers to remove the crystal from the open container to obtain GaOCl polycrystalline powder. (See...) Figure 16 )

[0087] By replacing the reaction vessel of the gel precursor with an open vessel, polycrystalline powder of GaOCl was obtained. The product was small in size and did not have a highly flat cleavage surface.

[0088] Example 4:

[0089] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0090] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140 degrees Celsius, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0091] S3: Take the translucent, high-viscosity gel precursor prepared in S2 and place it in an open container (see...). Figure 15 In the process of heating and evaporating crystals, the heating temperature is 380 degrees Celsius and the heating time is 5 days.

[0092] S4: Use tweezers to remove the reactants from the open container, obtaining a powder that is not the target product. (See...) Figure 17 )

[0093] Adjusting the temperature and time of the gel precursor reaction in an open container and using more vigorous reaction conditions did not yield crystals; the product was a white powder.

[0094] Example 5:

[0095] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0096] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140 degrees Celsius, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0097] S3: Take the semi-transparent and high-viscosity gel precursor prepared in S2, place it in a partially sealed glass test tube, and heat it to evaporate and crystallize. The heating temperature is 250-300 degrees Celsius, and the heating time is 4 days.

[0098] S4: Use tweezers to remove the reactants from the test tube, obtaining a crystalline product containing water. (See...) Figure 18 )

[0099] Replacing the reaction vessel for the gel precursor with a semi-open vessel may cause atmospheric moisture to be adsorbed by the crystals during the cooling process, disrupting the crystallization process and ultimately resulting in a crystalline product containing water.

[0100] Example 6:

[0101] S1: Place 2g of laboratory-grade high-purity gallium oxide (Ga2O3, purity 99.99%) in 6ml of excess concentrated hydrochloric acid (HCl, mass concentration 37%) for acid hydrolysis reaction, and stir until a transparent solution is generated;

[0102] S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140 degrees Celsius, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained.

[0103] S3: Take the translucent and high-viscosity gel precursor prepared in S2, place it in a CVT tube furnace, heat it with argon gas to evaporate and crystallize it, raise the temperature to 300 degrees Celsius at 5 degrees Celsius per minute, keep it at that temperature for three days, and then lower it to room temperature at 5 degrees Celsius per minute.

[0104] S4: Use tweezers to remove the reactants from the tube furnace. (See...) Figure 19 )

[0105] The reaction was carried out using a CVT tube furnace to ensure that the reaction was conducted in an inert gas atmosphere and that moisture could be carried away by the flowing inert gas. The resulting GaOCl nanosheets were deposited directly on top of the semi-dry gel precursor. The GaOCl nanosheets were thick and dense, and it was impossible to prepare an ideal nano-thin layer. This may be due to insufficient reaction or uneven reaction between the upper and lower layers of the reactants.

[0106] Example 7:

[0107] S1: Take 1.0313 g of high-purity gallium oxide (Ga2O3, purity 99.99%) and 0.9687 g of high-purity gallium chloride (GaCl3, purity 99.99%), with a molar ratio of 1:1, mix and grind to obtain 2 g of reactant powder.

[0108] S2: Place the powder into the bottom of a sealed vacuum quartz tube, and place the quartz tube in a dual-temperature zone reactor for reaction. The bottom is placed in the high-temperature zone and the top is placed in the low-temperature zone. The high-temperature zone is 450 degrees Celsius and the low-temperature zone is 370 degrees Celsius. The reaction lasts for 3 days.

[0109] S3: Use tweezers to remove the reactants from the crucible to obtain a powdered product.

[0110] Since it is a combination reaction of oxides and chlorides, the reaction temperature was insufficient, resulting in the reactants not reacting.

[0111] Example 8:

[0112] S1: Take 1.0313 g of high-purity gallium oxide (Ga2O3, purity 99.99%) and 0.9687 g of high-purity gallium chloride (GaCl3, purity 99.99%), with a molar ratio of 1:1, mix and grind to obtain 2 g of reactant powder.

[0113] S2: Place the powder into the bottom of a sealed vacuum quartz tube, and place the quartz tube in a dual-temperature zone reactor for reaction. The bottom is placed in the high-temperature zone and the top is placed in the low-temperature zone. The high-temperature zone is 750 degrees Celsius and the low-temperature zone is 450 degrees Celsius. The reaction lasts for 3 days.

[0114] S3: Use tweezers to remove the reactants from the crucible to obtain a powdered product.

[0115] The reactants did not react after the temperature was adjusted. This may be because the two reactants have significantly different melting points: gallium oxide has a melting point of 1740 degrees Celsius, while gallium chloride has a melting point of 77 degrees Celsius, making co-melting crystallization impossible.

Claims

1. A method for preparing large-size GaOCl single crystals using a pressure-assisted sol-gel method, characterized in that, Includes the following steps: S1: High-purity gallium oxide (Ga2O3) is placed in excess concentrated hydrochloric acid (HCl) for acid hydrolysis reaction, and stirred until a transparent solution is generated. S2: Take a certain amount of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it, finally obtaining a gel-like precursor. S3: Place a weight of a specific mass on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device; S4: Take the gel precursor prepared in S2, place it in the counterweight reaction furnace in S3, and heat it to evaporate and crystallize. S5: Remove the crystal from the inner wall of the counterweighted reactor to obtain transparent sheet-like GaOCl crystals; In step S2, the glass container is an open container that is heated in an air atmosphere; In step S3, the diameter of the lid of the covered glass dish is larger than the diameter of the glass dish, and there is a gap at the contact point between the two. The weight is located at the center of the lid and applies uniform pressure.

2. The method for preparing large-size GaOCl single crystals using the pressure-assisted sol-gel method according to claim 1, characterized in that, Includes the following steps: S1: Place 99.99% pure gallium oxide in an excess of 37% concentrated hydrochloric acid for acid hydrolysis reaction, and stir until a transparent solution is formed; S2: Take the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃, and the heating time is 8 hours, finally obtaining a translucent gel-like precursor with high viscosity. S3: Place a weight of a specific mass on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device; S4: Take the semi-transparent and high-viscosity gel precursor prepared in S2, place it in the counterweight reaction furnace in S3, and heat it to evaporate and crystallize. S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

3. The method for preparing large-size GaOCl single crystals using the pressure-assisted sol-gel method according to claim 1, characterized in that, Includes the following steps: S1: High-purity gallium oxide is placed in excess concentrated hydrochloric acid for acid hydrolysis reaction, and stirred until a transparent solution is generated; S2: Take the transparent solution from step S1, place it in a glass container and heat it on a hot plate to evaporate it. The heating temperature is 140℃ and the heating time is 8h. Finally, a semi-transparent gel-like precursor with high viscosity is obtained. S3: Place a weight of a specific mass on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device; S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250℃ and the heating time is 2.5 days. S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

4. The method for preparing large-size GaOCl single crystals using the pressure-assisted sol-gel method according to claim 1, characterized in that, Includes the following steps: S1: High-purity gallium oxide is placed in excess concentrated hydrochloric acid for acid hydrolysis reaction, and stirred until a transparent solution is generated; S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140 degrees Celsius, and the heating time is 8 hours. Finally, a semi-transparent gel-like precursor with high viscosity is obtained. S3: Place a 200g weight on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device; S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250℃ and the heating time is 2.5 days. S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain a well-grown transparent sheet. Crystal.

5. The method for preparing large-size GaOCl single crystals using the pressure-assisted sol-gel method according to claim 1, characterized in that, Includes the following steps: S1: Place 2g of 99.99% pure gallium oxide (for laboratory use) in 6ml of 37% concentrated hydrochloric acid for acid hydrolysis reaction, and stir until a transparent solution is formed; S2: Take 2 ml of the transparent solution from step S1, place it in a glass container, and heat it on a hot plate to evaporate it. The heating temperature is 140℃ and the heating time is 8h. Finally, a semi-transparent gel-like precursor with high viscosity is obtained. S3: Place a 200g weight on top of the lid of a covered glass dish to form a reaction furnace with a counterweight device; S4: Take the translucent and high-viscosity gel precursor prepared in S2, place it in the counterweighted reaction furnace in S3, and heat it to evaporate and crystallize. The heating temperature is 250℃ and the heating time is 2.5 days. S5: Use tweezers to remove the crystal from the inner wall of the counterweighted reactor to obtain well-grown transparent plate-like GaOCl crystals.

6. The application of the pressure-assisted sol-gel method for preparing large-size GaOCl single crystals according to claim 1, characterized in that, It is used in transistor devices, deep ultraviolet photodetectors, or high-stability electronic devices.

7. The application of the pressure-assisted sol-gel method for preparing large-size GaOCl single crystals according to claim 1, characterized in that, Using a mechanical exfoliation method, two-dimensional GaOCl nanosheets were torn from the GaOCl single crystal obtained in S5 under a microscope to construct a bottom-gate field-effect transistor as the gate dielectric layer. This device uses Bi / Au as the source and drain electrodes, and a monolayer MoS2 as the conductive channel. The entire device is constructed on a silicon substrate. The source and drain currents of this device were measured as a function of different source and drain voltages V. ds and gate-source voltage V g The changes under the given conditions were analyzed to obtain the transfer characteristic curve and the output characteristic curve. The transfer characteristic curve shows that the subthreshold swing SS of the device is 100 mV / dec, and the on / off ratio reaches 10. 8 This material has excellent turn-off capability and low static power consumption. As can be seen from the output characteristic curve, the curve is a straight line at low leakage voltage, and the device exhibits perfect ohmic contact with low contact resistance. It is applied to novel transistor devices, deep ultraviolet photodetectors, or high-stability electronic devices.

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