Preparation method of two-dimensional indium nitride and indium oxide composite structure and product

Abstract

The invention relates to a preparation method of a two-dimensional indium nitride and indium oxide composite structure and a product, and aims to solve the problems that direct nitridation of two-dimensional indium oxide into indium nitride is relatively difficult, relatively high synthesis temperature is required, and the thermal decomposition temperature of an InN material is relatively low. The two-dimensional indium oxide is converted into indium bromide which is more easily nitrided, the synthesis temperature is reduced, the problem that indium oxide is not easy to nitride is solved, and large-scale synthesis of the two-dimensional indium nitride-indium oxide composite material is completed under a harmless nitrogen source, so that processing and manufacturing of subsequent devices are facilitated.

Description

Technical Field

[0001] The present invention relates to the field of two-dimensional nanomaterials, and in particular to a preparation method and product of a two-dimensional indium nitride indium oxide composite structure. Background Art

[0002] The research on two-dimensional (2D) nanomaterials has received increasing attention. Two-dimensional nanomaterials have ultra-thin thickness and large lateral size, excellent electrical properties, ultra-high specific surface area and excellent mechanical properties, etc. Nanocrystals with different compositions, structures and (crystalline) phases have been prepared. At the same time, people are also exploring the potential applications of these two-dimensional nanomaterials. Hybridizing two or more nanomaterials to prepare new composite materials can effectively integrate the advantages of each component, thereby optimizing its performance to meet specific application requirements.

[0003] As the third generation semiconductor, group III nitrides have broad application prospects in high-power electronic and optoelectronic devices due to their unique characteristics such as wide band gap and high electron saturation mobility. III nitride materials mainly refer to aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN) and their alloys (AlGaN, InGaN, AlInN, AlGaInN, the band width is determined by the composition ratio of the alloy). InN has the lowest effective electron mass among all group III nitride semiconductors, which makes it have faster carrier mobility and higher saturation velocity. At 300K, the theoretical value of InN carrier mobility is up to 4400cm 2 ·V -1 s -1 , much higher than GaN (1000cm 2 ·V -1 s -1 ), this characteristic indicates that indium nitride may be more suitable for optoelectronic devices than gallium nitride. However, the synthesis of two-dimensional indium nitride is difficult. The growth process of InN crystals requires a higher nitrogen equilibrium vapor pressure and a higher reaction temperature, while the thermal decomposition temperature of InN materials is relatively low (~520°C). As an important semiconductor material, two-dimensional indium oxide (In2O3) has broad application prospects in transparent conductive films, gas sensors, photocatalysis and other fields due to its unique electronic structure and excellent optoelectronic properties. It is also easy to synthesize and has low cost. At present, Ning Qiuyang and others have successfully prepared InN-In2O3 composite materials and applied them to gas sensors. The sensor has good selectivity for formaldehyde gas and exhibits strong stability. Overall, there is little research on two-dimensional indium nitride indium oxide composites, so studying its composite structure has strong scientific significance and practical value.

[0004] The prior art has the following defects:

[0005] (1) The existing method of converting two-dimensional indium oxide into indium nitride requires a higher nitrogen equilibrium vapor pressure and a higher reaction temperature during the nitridation growth process. However, the thermal decomposition temperature of InN material is relatively low (~520°C), which easily forms In clusters on the surface of the product, reducing the crystal quality of the film and causing difficulties in the growth of two-dimensional indium nitride and indium oxide composite structures; (2) The traditional method of preparing indium nitride mainly uses ammonia as a nitrogen source for high-temperature reaction, which has high requirements for production equipment, production costs and production technology. Ammonia is highly corrosive and can easily damage equipment. It can also cause environmental pollution and endanger human health. (3) Preparation of existing two-dimensional composite materials The preparation of two-dimensional composite materials often requires high-temperature or high-vacuum equipment. Although low-cost methods (such as solution method and self-assembly method) are simple, they are prone to unstable material quality, more defects, and complex preparation process and long preparation time. Summary of the invention

[0006] It is difficult to directly nitride two-dimensional indium oxide into indium nitride, which requires a higher synthesis temperature. However, the thermal decomposition temperature of InN material is relatively low. Therefore, a hydrogen bromide fumigation step is introduced before nitridation to convert the two-dimensional indium oxide into indium bromide, which is more easily nitrided. This reduces the synthesis temperature and solves the problem that indium oxide is difficult to nitridate. The large-scale synthesis of two-dimensional indium nitride-indium oxide composite materials is completed under a harmless nitrogen source to facilitate the subsequent processing and manufacturing of devices.

[0007] The present invention provides a method for preparing a two-dimensional indium nitride indium oxide composite structure, comprising the following steps:

[0008] S1 uses indium-based liquid metal to produce a two-dimensional indium oxide film on an oxide silicon wafer;

[0009] S2: treating the surface of the indium oxide film that is not in contact with the silicon oxide wafer with hydrogen bromide to obtain an indium bromide film on the surface of the indium oxide film;

[0010] S3 obtains a nitrogen source, and uses a chemical vapor deposition method to convert the indium bromide film into an indium nitride film, thereby obtaining a two-dimensional indium nitride indium oxide composite film on the silicon oxide substrate.

[0011] Preferably, S1 specifically includes the following steps: obtaining a metal indium coating on a silicon oxide substrate by squeezing liquid metal indium droplets through a silicon oxide wafer; heating the coated silicon oxide substrate to oxidize the metal indium to obtain a two-dimensional In2O3 film, and removing the metal indium residue on the surface of the two-dimensional In2O3 film.

[0012] Preferably, in S2, the treatment with hydrogen bromide specifically includes the following steps: fumigating the two-dimensional indium oxide film with hydrogen bromide.

[0013] Preferably, the fumigating the two-dimensional indium oxide film with hydrogen bromide specifically comprises: placing the hydrogen bromide solution on a 60° C. heating table, and fumigating the two-dimensional indium oxide film for 30 seconds after stable white smoke floats out of the bottle mouth; obtaining an indium bromide film on the surface of the indium oxide film, specifically comprising: on the fumigated two-dimensional indium oxide film,

[0014] Add anhydrous ethanol and place on a heating table to dry to allow InBr3 to repolymerize into a film.

[0015] Preferably, S3 specifically includes the following steps: obtaining urea as a nitrogen source, placing the prepared silicon oxide wafer with indium bromide film upside down on a quartz boat, and placing urea powder in another quartz boat; loading the quartz boat into a tubular furnace, heating it with the tubular furnace, and introducing nitrogen gas as a carrier gas during the reaction; placing urea powder upstream of the carrier gas flow direction, and placing the silicon oxide wafer downstream of the carrier gas flow direction; performing a chemical vapor deposition reaction under low pressure conditions of 150-250Pa to convert the indium bromide film into an indium nitride film, and obtaining a two-dimensional indium nitride indium oxide composite film on the silicon oxide substrate.

[0016] Preferably, the heating with a tubular furnace specifically includes: a heating temperature range of 580-630°C, a heating rate of 20°C / min, and a maximum temperature holding time of 30-60min; the urea powder is placed upstream of the carrier gas flow direction, specifically about 4-5cm from the central temperature zone; the silicon oxide wafer is placed downstream of the carrier gas flow direction, specifically about 4-5cm from the central temperature zone; the flow rate of the carrier gas is 50-100sccm.

[0017] Preferably, the removal of the metal indium residues on the surface of the two-dimensional In2O3 film specifically includes the following steps: at 200°C, wiping the surface of the two-dimensional In2O3 film with a cotton ball soaked in anhydrous ethanol to remove the metal indium residues.

[0018] The present invention also provides a product obtained by a method for preparing a two-dimensional indium nitride indium oxide composite structure, which is composed of a silicon oxide substrate, a two-dimensional indium oxide layer, and a two-dimensional indium nitride layer from bottom to top; the thickness of the two-dimensional indium oxide layer is in the range of 5-20nm, and the total thickness of the two-dimensional indium oxide layer and the two-dimensional indium nitride layer is in the range of 40-90nm.

[0019] The present invention solves the problem that the existing two-dimensional composite material synthesis method has a complex technical process and high cost. The preparation method uses abundant raw materials, low price, and simple preparation method, which provides a new idea for the future preparation of two-dimensional composite materials. The present invention can realize the controllable preparation of large-area two-dimensional materials, and obtain a large-size, atomic layer thin single-crystal indium oxide intermediate product; using non-toxic urea as a nitrogen source, the final product, two-dimensional indium oxide indium nitride composite material, has good surface flatness and a thickness of about 50nm, which proves that it belongs to the category of two-dimensional materials, and the material is prepared on an oxide silicon wafer, which can be used to prepare a two-dimensional photodetector, which is convenient for subsequent device processing and manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific implementation or the prior art description. Some specific embodiments of the present invention will be described in detail in an exemplary but not restrictive manner with reference to the drawings. The same reference numerals in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0021] Figure 1 It is a schematic diagram of the process of preparing two-dimensional indium oxide by liquid metal method and removing surface metal indium particles;

[0022] Figure 2 It is a schematic diagram of the process of converting two-dimensional In2O3 into InBr3 by HBr fumigation;

[0023] Figure 3 Schematic diagram of preparing two-dimensional indium nitride and indium oxide composite materials by chemical vapor deposition in a single temperature zone tube furnace;

[0024] Figure 4 This is a schematic diagram of the XPS characterization results of the oxygen element of the sample. In the figure, the peak at ~530.5eV corresponds to the oxygen bound in In2O3, while the peak at ~532.38eV can be attributed to the SiO2 substrate.

[0025] Figure 5 This is a schematic diagram of the XPS characterization results of the oxygen and nitrogen elements of the sample. The peak at ~396.5 eV in the figure corresponds to the N1s peak of InN, proving that the sample is an indium nitride indium oxide composite structure;

[0026] Figure 6 This is a device diagram of a two-terminal device based on a two-dimensional indium nitride and indium oxide composite structure. The metal electrodes pressed on both ends of the material can also be replaced by silver glue. The material has good light-sensing properties and can be used as a photodetector. Under normal temperature and atmospheric environment, a probe station is used to obtain the current-voltage characteristic curve. ;

[0027] Figure 7The IV characteristic curves of the two-terminal device under different wavelength laser illumination (a) and the IV curves of different power densities under 365nm wavelength illumination (b). In (a), when the wavelength of the light source is 365nm, the device has the strongest absorption of light, and as the wavelength increases, the device light response decreases, and the current value in the dark state is the smallest. At the same time, it can be seen from (b) that the greater the light intensity under the same bias voltage, the greater the photocurrent, indicating that the device is expected to be used in ultraviolet detection;

[0028] Figure 8 This is a schematic diagram of the thickness measurement of a two-dimensional indium oxide film. The measured thickness is 8nm and the sample thickness ranges from 5-20nm.

[0029] Fig. 9 Schematic diagram of the thickness measurement of two-dimensional indium nitride-indium oxide composite film. The measured thickness is 70nm and the sample thickness range is between 40-90nm. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present application more clear, the present application is further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] This technical solution is realized by chemical vapor deposition. Chemical vapor deposition technology is a process that uses gaseous substances to produce chemical reactions and transmission reactions on solids and produce solid deposits. For this technology, it generally includes three steps:

[0032] (1) Using indium-based liquid metal to prepare a two-dimensional indium oxide film on an oxide silicon wafer;

[0033] (2) The two-dimensional indium oxide film is converted into indium bromide by fumigation with hydrogen bromide.

[0034] (3) The indium bromide film and the nitrogen source urea (CH4N2O) are placed in a tube furnace for CVD reaction to produce a two-dimensional indium nitride-indium oxide composite film on a silicon oxide substrate.

[0035] The method for preparing the two-dimensional indium nitride indium oxide composite structure provided by the present invention specifically comprises the following steps:

[0036] (1) Place a glass sheet on a heating plate at 200°C, place an indium droplet with a radius of about 0.5 to 10 mm on the glass sheet and melt it;

[0037] (2) Using a silicon oxide wafer to squeeze the indium droplets downward to form a film on the silicon oxide substrate;

[0038] (3) placing the coated silicon oxide substrate on a 200°C heating plate, and "gently" wiping its surface with a cotton ball soaked in anhydrous ethanol to remove the indium metal residue, thereby obtaining a two-dimensional In2O3 film on the silicon oxide wafer;

[0039] (4) Place the bottle on a 60°C heating platform with a hydrogen bromide solution and wait for stable white smoke to float out of the bottle mouth before fumigating the two-dimensional indium oxide film for 30 seconds to convert it into indium bromide.

[0040] (5) A drop of anhydrous ethanol is dropped on the surface of the above sample and then placed on a heating table for drying. The volatility of anhydrous ethanol is used to repolymerize the InBr3 obtained after HBr fumigation into a film.

[0041] (6) Place the prepared silicon oxide wafer with InBr3 upside down on a quartz boat, and place 0.5-2g of ground CH4N2O powder in another quartz boat;

[0042] (7) Using a tubular furnace, the preparation temperature range is 580-630°C, the heating rate is 20°C / min, and the maximum temperature holding time is 30-60min;

[0043] (8) CH4N2O powder is placed about 4-5 cm from the central temperature zone, and the silicon oxide wafer is placed about 4-5 cm from the central temperature zone;

[0044] (9) During the reaction, nitrogen gas was introduced as a carrier gas (50-100 sccm) and the reaction was prepared under low pressure of 150-250 Pa.

[0045] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] See also Figure 1 Schematic diagram of the process of In metal liquefaction and surface oxide layer transfer. Liquid metal indium (In) (>99.9%) is used as the indium source. A glass sheet is placed on a 200℃ hot plate. Indium particles with a radius of about 1mm are placed on the glass sheet. The cleaned silicon oxide / silicon substrate is gently squeezed with the front side facing down to coat the silicon oxide substrate. Since the van der Waals interaction between In2O3 and the oxygen-containing sheet is stronger than the interaction with metal In, the In2O3 film can be peeled off from the metal surface. A cotton ball soaked in a small amount of anhydrous ethanol solution is gently wiped on the surface of the silicon oxide sheet containing In2O3 (with In particles) to remove the In particles, a two-dimensional In2O3 film (thickness ≤10nm) can be obtained on the silicon oxide sheet.

[0047] See also Figure 2 Schematic diagram of the process of converting two-dimensional In2O3 into InBr3 by HBr fumigation. The hydrogen bromide solution is placed on a 60°C heating table. After stable white smoke floats out of the bottle mouth, a silicon wafer with a two-dimensional indium oxide film is placed on the bottle mouth for 30 seconds to convert indium oxide into indium bromide. Subsequently, a drop of anhydrous ethanol is dropped on the surface of the above sample and placed on the heating table for drying.

[0048] See also Figure 3 Schematic diagram of preparing two-dimensional indium nitride and indium oxide composite materials by chemical vapor deposition in a single-temperature-zone tube furnace. The sample from the previous step is placed upside down on a quartz boat, about 5 cm downstream of the central temperature zone of the vacuum tube furnace. The quartz boat filled with CH4N2O powder is placed about 5 cm upstream of the central temperature zone of the vacuum tube furnace.

[0049] Before the tube furnace starts working, it is pre-evacuated to about 250Pa, then filled with 500sccm N2 to atmospheric pressure, and the gas is repeatedly purged at least 3 times to remove the remaining air.

[0050] During the reaction, N2 (50-100 sccm) was introduced and the pressure was maintained at about 250 Pa. The reaction temperature was set at 630°C, the heating rate was 20°C / min, and the temperature was kept at 630°C for 30 minutes. The entire reaction process took about 60 minutes.

[0051] After the reaction is completed, the carrier gas remains unchanged, the product is naturally cooled to room temperature, and the reaction product is on the silicon oxide wafer.

[0052] The above descriptions are only some specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any person familiar with the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a two-dimensional indium nitride-indium oxide composite structure, characterized in that: The following steps are involved: S1 uses indium-based liquid metal to produce a two-dimensional indium oxide film on a silicon oxide wafer; S2: treating the surface of the indium oxide film that is not in contact with the silicon oxide wafer with hydrogen bromide to obtain an indium bromide film on the surface of the indium oxide film; S3 obtains a nitrogen source, and uses a chemical vapor deposition method to convert the indium bromide film into an indium nitride film, thereby obtaining a two-dimensional indium nitride indium oxide composite film on the silicon oxide substrate.

2. The method for preparing a two-dimensional indium nitride-indium oxide composite structure according to claim 1, characterized in that: S1 specifically includes the following steps: A metal indium coating is obtained on a silicon oxide substrate by squeezing liquid metal indium droplets through a silicon oxide wafer; the coated silicon oxide substrate is heated to oxidize the metal indium to obtain a two-dimensional In2O3 film, and the metal indium residue on the surface of the two-dimensional In2O3 film is removed.

3. The method for preparing a two-dimensional indium nitride-indium oxide composite structure according to claim 1, characterized in that: In S2, the treatment with hydrogen bromide specifically comprises the following steps: Fumigation of two-dimensional indium oxide thin films using hydrogen bromide.

4. The method for preparing a two-dimensional indium nitride-indium oxide composite structure according to claim 3, characterized in that: The fumigating of the two-dimensional indium oxide film with hydrogen bromide specifically includes: Place the hydrogen bromide solution on a 60°C heating table, and fumigate the two-dimensional indium oxide film for 30 seconds after stable white smoke floats out of the bottle mouth; Obtaining an indium bromide film on the surface of the indium oxide film specifically comprises: on the fumigated two-dimensional indium oxide film, Add anhydrous ethanol and place on a heating table to dry to allow InBr3 to repolymerize into a film.

5. The method for preparing a two-dimensional indium nitride-indium oxide composite structure according to claim 1, characterized in that: S3 specifically includes the following steps: Urea is obtained as a nitrogen source, the prepared silicon oxide wafer with an indium bromide film is placed upside down on a quartz boat, and urea powder is placed in another quartz boat; The quartz boat was loaded into a tube furnace and heated by the tube furnace, and nitrogen gas was introduced as a carrier gas during the reaction; The urea powder is placed upstream of the carrier gas flow direction, and the silicon oxide sheet is placed downstream of the carrier gas flow direction; A chemical vapor deposition reaction is carried out under low pressure of 150-250 Pa to convert the indium bromide film into an indium nitride film, thereby obtaining a two-dimensional indium nitride indium oxide composite film on the silicon oxide substrate.

6. The method for preparing a two-dimensional indium nitride-indium oxide composite structure according to claim 5, characterized in that: The heating with a tubular furnace specifically includes: a heating temperature range of 580-630°C, a heating rate of 20°C / min, and a maximum temperature holding time of 30-60min; The urea powder is placed upstream of the carrier gas flow direction, specifically about 4-5 cm away from the central temperature zone; The silicon oxide wafer is placed downstream of the carrier gas flow direction, specifically about 4-5 cm away from the central temperature zone; The flow rate of the carrier gas is 50-100 sccm.

7. The method for preparing a two-dimensional indium nitride-indium oxide composite structure according to claim 2, characterized in that: The method of removing the metal indium residue on the surface of the two-dimensional In2O3 film specifically comprises the following steps: At 200°C, the surface of the two-dimensional In2O3 film was wiped with a cotton ball soaked in anhydrous ethanol to remove the metal indium residue.

8. The product obtained by the method for preparing a two-dimensional indium nitride indium oxide composite structure according to any one of claims 1 to 7, characterized in that: From bottom to top, it is composed of a silicon oxide substrate, a two-dimensional indium oxide layer, and a two-dimensional indium nitride layer; the thickness of the two-dimensional indium oxide layer ranges from 5 to 20 nm, and the total thickness of the two-dimensional indium oxide layer and the two-dimensional indium nitride layer ranges from 40 to 90 nm.

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