Preparation method of graphene oxide semiconductor thin film with adjustable band gap, graphene oxide semiconductor thin film and application thereof

Abstract

The application provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, the graphene oxide semiconductor film and application thereof. The preparation method comprises the following steps: graphene oxide solution is sprayed onto the surface of a substrate by using an ultrasonic atomization spraying method, and heat treatment is simultaneously performed to obtain the graphene oxide semiconductor film with adjustable band gap; wherein the temperature of the heat treatment is 120-340 DEG C. The preparation method of the graphene oxide semiconductor film adopts the method of ultrasonic atomization spraying and simultaneous heat treatment. Through continuously stacking graphene oxide layers and adjusting the band gap of the graphene oxide while stacking the layers, the graphene oxide semiconductor film with the following characteristics can be finally obtained: complete structure, good uniformity, controllable band gap, excellent conductive performance, and the thickness is in the range of hundreds of nanometers to microns.

Description

Technical Field

[0001] This invention relates to the field of graphene material preparation technology, and in particular to a method for preparing a graphene oxide semiconductor thin film with an adjustable bandgap, the graphene oxide semiconductor thin film and its applications. Background Technology

[0002] A PN junction is an extremely important semiconductor structure, typically formed by the close contact of a P-type semiconductor and an N-type semiconductor (e.g., ...). Figure 1 (As shown). Due to its unique unidirectional conductivity and photoelectric effect, the PN junction is widely used as a core component in semiconductor devices such as logic gates, light-emitting diodes (LEDs), and photovoltaic cells. As a core component of logic gates, LEDs, and photovoltaic cells, the semiconductor properties of the PN junction material directly affect the performance of semiconductor devices, especially optoelectronic devices. In photovoltaic cells, the bandgap of the PN junction material directly determines the solar energy utilization efficiency of the photovoltaic cell, while the structural integrity and conductivity of the PN junction material directly determine its energy utilization efficiency. Achieving flexible adjustment of the bandgap of the PN junction material is of great significance for optoelectronic devices such as LEDs and photovoltaic cells.

[0003] Currently, inorganic semiconductor materials are mainly used to prepare PN junctions. Inorganic semiconductor materials have advantages such as ease of processing and stable properties. However, in the face of complex practical needs, inorganic semiconductors have gradually shown the following shortcomings: (1) Inorganic semiconductors lack bandgap flexibility, and their bandgap is difficult to adjust flexibly for different needs; (2) The preparation and purification of inorganic semiconductors need to be carried out at high temperatures, which are often accompanied by high pollution, high energy consumption and large carbon emissions; (3) Some inorganic semiconductor-related elements, such as arsenic, gallium and indium, have limited reserves in the earth's crust, which is difficult to meet the growing demand of the semiconductor industry; (4) Inorganic semiconductor materials generally lack flexibility and are difficult to use on flexible surfaces or curved surfaces. Under external force or during repeated heating and cooling, structural defects are easily generated, affecting their long-term performance. In view of the above shortcomings of inorganic semiconductors, seeking a semiconductor material with high bandgap flexibility, abundant reserves, easy preparation and excellent material flexibility has become a key research goal in PN junction materials science and engineering.

[0004] Recent studies have shown that graphene oxide possesses a certain degree of band structure flexibility, making it a promising candidate for next-generation PN junction semiconductor materials. Graphene oxide is a derivative of graphene, primarily prepared through liquid-phase oxidation of high-purity graphite. Compared to graphene, graphene oxide contains a large number of hydrophilic oxygen-containing functional groups, mainly including hydroxyl, epoxy, carboxyl, and carbonyl groups, exhibiting superior solubility and dispersibility in water and some organic solvents. Due to the disruption of delocalized π bonds on graphene sheets by these oxygen-containing functional groups and structural defects, the carrier mobility of graphene oxide (0.1–2 cm⁻¹) is significantly reduced. 2 ·V-1 ·s -1 ) far less than that of graphene (2-25 x 10 4 cm 2 ·V -1 ·s -1 ). A number of experimental results show that the band gap of graphene oxide can be adjusted by oxidation or reduction reactions. As shown in Figure 2 , the oxidation reaction can increase the band gap of graphene oxide, while the reduction reaction can decrease the band gap of graphene oxide. In addition, the results of related theoretical simulation also show that there is a significant positive correlation between the band gap of graphene oxide and the oxygen-carbon atomic ratio in graphene oxide.

[0005] Due to the unique band gap plasticity of graphene oxide, as well as its abundant reserves, low preparation cost, low energy consumption and low carbon emissions in the preparation process, graphene oxide has great potential in PN junction related applications and even in the semiconductor industry. How to prepare graphene oxide semiconductor thin films with good structural uniformity, controllable band gap and excellent electrical conductivity is of great research significance for building band gap adjustable PN junction and improving the performance of photovoltaic cells and light emitting diodes.

[0006] The main difficulty in preparing graphene oxide semiconductor thin films lies in the process conflict between the band adjustment process and the film formation process. The band adjustment process of graphene oxide (including heat treatment, light treatment and chemical treatment, etc.) is often accompanied by dehydration, decarboxylation and other chemical reactions, and at the same time generates water vapor, carbon dioxide and other gases. If graphene oxide thin films are prepared first and then the band adjustment process is performed, the gases generated in the band adjustment process will destroy the film structure of graphene oxide during the escape process, seriously damaging its structural integrity, uniformity and electrical conductivity. If the band gap of graphene oxide is adjusted first, the solubility of graphene oxide in hydrophilic solvents will be significantly reduced. Graphene oxide with greatly reduced solubility is basically not applicable to liquid phase film forming technology, and can only be used for film forming by vacuum filtration, etc., and the uniformity of its product is far inferior to that of liquid phase film forming product. How to realize the organic integration of graphene oxide band adjustment technology and film preparation technology is of great significance for preparing graphene oxide semiconductor thin films with good structural uniformity, controllable band gap and excellent electrical conductivity, and building band gap adjustable PN junction.

[0007] In view of this, the present application is proposed. SUMMARY

[0008] One of the purposes of the present application is to provide a preparation method of graphene oxide semiconductor thin film with adjustable band gap. The preparation method of the present application uses heat treatment method to regulate the unsaturation and functional group concentration of graphene oxide. Compared with other methods for adjusting the band gap of graphene oxide, the heat treatment method is continuous, has high adjustment accuracy and is easy to operate, and is suitable for regulating the band gap of large-size graphene oxide semiconductor thin film.

[0009] The second purpose of the present application is to provide a graphene oxide semiconductor thin film prepared by the preparation method of graphene oxide semiconductor thin film with adjustable band gap as described above. By continuously stacking graphene oxide layers, a graphene oxide semiconductor thin film with good structural uniformity, uniform texture and thickness of hundreds of nanometers to microns can be finally obtained.

[0010] The third purpose of the present application is to provide an application of the graphene oxide semiconductor thin film in preparing semiconductor elements. The graphene oxide semiconductor thin film can be used to prepare PN junction, photoelectric element, temperature sensor, conductive layer, heat conducting layer, optical filter and other semiconductor elements.

[0011] In order to achieve the above purposes of the present application, the following technical solutions are adopted:

[0012] In a first aspect, the present application provides a preparation method of graphene oxide semiconductor thin film with adjustable band gap, which comprises the following steps:

[0013] (a) first heat the substrate to a first heat treatment temperature, and spray the graphene oxide solution onto the surface of the substrate by ultrasonic atomization at the first heat treatment temperature to form a first contact layer; wherein the first heat treatment temperature is a temperature 20-40℃ higher than the gasification point temperature of the organic solvent.

[0014] It should be noted that in step (a), the temperature of the substrate needs to be heated to a specified temperature required for the deposition and preparation of the graphene oxide contact layer before ultrasonic atomization spraying, and the specified temperature is 20-40℃ higher than the gasification point temperature of the organic solvent, for example, it can be 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 38℃, 40℃; that is, the first heat treatment temperature = the gasification point temperature of the organic solvent + (any value in the range of 20-40℃).

[0015] (b) then heat the substrate to a second heat treatment temperature, and spray the graphene oxide solution onto the surface of the first contact layer by ultrasonic atomization at the second heat treatment temperature to form a second contact layer; wherein the second heat treatment temperature is 120-340℃.

[0016] It should be noted that in step (b), the substrate is heated to the specified heat treatment temperature. The heat treatment temperature ranges from 120 to 340℃, and since the heat treatment temperature directly determines the band gap of the graphene oxide semiconductor film, the heat treatment temperature needs to be selected according to the target band gap. In general, the higher the heat treatment temperature, the lower the band gap of the obtained graphene oxide semiconductor film. The second heat treatment temperature is 120-340℃, for example, it can be 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, etc.

[0017] In the preparation method of the graphene oxide semiconductor film, the unsaturation and functional group concentration of graphene oxide are regulated by using a heat treatment method. Compared with other methods for adjusting the band gap of graphene oxide, the heat treatment method has the advantages of continuous regulation, high regulation accuracy and simple operation, and is suitable for regulating the band gap of large-size graphene semiconductor films.

[0018] Preferably, the substrate is a quartz sheet with a purity of >99%.

[0019] Preferably, the substrate is a high-purity quartz sheet with a purity of >99%, for example, it can be 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, etc., and further preferably 99.9%.

[0020] Preferably, the thermal expansion coefficient of the quartz sheet is <7×10 -6 / K, for example, it can be 6.9×10 -6 / K, 6.5×10 -6 / K, 6×10 -6 / K, 5.5×10 -6 / K, 5×10 -6 / K, 4.5×10 -6 / K, 4×10 -6 / K, 3.5×10 -6 / K, 3×10 -6 / K, 2.5×10 -6 / K, 2×10 -6 / K, 1.5×10 -6 / K, 1×10 -6 / K, etc., and further preferably 2×10 -6 / K.

[0021] Preferably, the electrical conductivity of the quartz sheet is <10 -10S / cm, for example, can be 1 x 10 -10 S / cm, 5 x 10 -11 S / cm, 1 x 10 -11 S / cm, 5 x 10 -12 S / cm, 1 x 10 -12 S / cm, 5 x 10 -13 S / cm, 1 x 10 -13 S / cm, 5 x 10 -14 S / cm, 1 x 10 -14 S / cm, 5 x 10 -15 S / cm, 1 x 10 -15 S / cm, etc., further preferably 1 x 10 -14 S / cm.

[0022] Preferably, the length of the quartz sheet is 10-100 mm, for example, can be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc., further preferably 40 mm.

[0023] Preferably, the width of the quartz sheet is 10-50 mm, for example, can be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc., further preferably 20 mm.

[0024] Preferably, the thickness of the quartz sheet is 0.5-1.5 mm, for example, can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc., further preferably 1 mm.

[0025] Preferably, the surface roughness of the quartz sheet is 5-10 nm, for example, can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.

[0026] Preferably, the absorption rate of the quartz sheet under visible light is <10%, for example, can be 9.9%, 9.5%, 9%, 8%, 7%, 6%, 5%, etc., further preferably 6%. Wherein, the wavelength range of the visible light is 400-780 nm.

[0027] Preferably, the absorption rate of the quartz sheet under near-infrared light is <10%, for example, can be 9.9%, 9.5%, 9%, 8%, 7%, 6%, etc., further preferably 8%. Wherein, the wavelength range of the near-infrared light is 780-2526 nm.

[0028] Preferably, the quartz wafer has an absorption rate of <20% under near-ultraviolet light, such as 19.9%, 19.5%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, and the like, and further preferably 11%. The near-ultraviolet light has a wavelength range of 300-400 nm.

[0029] Preferably, the graphene oxide solution has a wetting angle of <30° on the surface of the quartz wafer, such as 29°, 28°, 27°, 25°, 24°, 23°, 22°, 21°, 20°, 15°, 12°, 10°, 5°, 1°, and the like.

[0030] Preferably, the surface of the quartz wafer should be preferentially subjected to plasma surface treatment before spraying to remove surface impurities, adsorbed gas, and charge.

[0031] Preferably, the plasma surface treatment can use atmospheric pressure low-temperature plasma surface treatment and vacuum plasma surface treatment, and further preferably vacuum plasma surface treatment.

[0032] Preferably, the plasma surface treatment has a voltage of 3-12 kV, such as 3 kV, 4 kV, 5 kV, 6 kV, 7 kV, 8 kV, 9 kV, 10 kV, 11 kV, 12 kV, and the like, a time of 60-300 s, such as 60 s, 80 s, 100 s, 120 s, 140 s, 160 s, 180 s, 200 s, 220 s, 240 s, 260 s, 280 s, 300 s, and the like, an absolute pressure in the vacuum chamber of 100-1500 Pa, such as 100 Pa, 250 Pa, 500 Pa, 750 Pa, 1000 Pa, 1250 Pa, 1500 Pa, and the like, and a radio frequency power of 150-750 W, such as 150 W, 200 W, 250 W, 300 W, 350 W, 400 W, 450 W, 500 W, 550 W, 600 W, 650 W, 700 W, 750 W, and the like.

[0033] Preferably, the graphene oxide solution has a wetting angle of <30° on the surface of the quartz wafer after treatment, and further preferably <15°.

[0034] Preferably, the graphene oxide solution has a concentration of 0.1-1.0 mg / mL, such as 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, 0.9 mg / mL, 1.0 mg / mL, and the like, and further preferably 0.5 mg / mL.

[0035] Preferably, the graphene oxide solution comprises graphene oxide, water and an organic solvent.

[0036] Preferably, the volume ratio of the water and the organic solvent is 1:(5-15), for example, it can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, etc., and further preferably 1:9.

[0037] Preferably, the organic solvent is selected from C1-C3 monohydric alcohol and / or C3-C5 monoketone, and further preferably C1-C3 monohydric alcohol.

[0038] Preferably, the monohydric alcohol is selected from any one or a combination of at least two of methanol, ethanol, n-propanol or isopropanol.

[0039] Preferably, the monoketone is selected from any one or a combination of at least two of acetone, 2-butanone, 2-pentanone, 3-pentanone.

[0040] As an optional technical solution of the present application, the graphene oxide solution is prepared by the following method: adding an organic solvent to a graphene oxide aqueous solution to dilute to obtain a graphene oxide solution.

[0041] Preferably, the concentration of the graphene oxide aqueous solution is 1-10 mg / mL, for example, it can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, etc., and further preferably 5 mg / mL.

[0042] Preferably, in terms of the total content of each element in the graphene oxide being 100%, the proportion of carbon element in the graphene oxide is 45-47%, the proportion of hydrogen element is <2%, the proportion of nitrogen element is <2%, the proportion of sulfur element is <1%, and the remaining elements are all oxygen.

[0043] Preferably, the proportion of carbon element is 45-47%, for example, it can be 45%, 45.5%, 46%, 46.5%, 47%, etc.

[0044] Preferably, the proportion of hydrogen element is <2%, for example, it can be 1.9%, 1.8%, 1.6%, 1.4%, 1.2%, 1.0%, 0.5%, 0.2%, 0.1%, etc.

[0045] Preferably, the proportion of nitrogen element is <2%, for example, it can be 1.9%, 1.8%, 1.6%, 1.4%, 1.2%, 1.0%, 0.5%, 0.2%, 0.1%, etc.

[0046] The proportion of sulfur element is <1%, for example, it can be 0.9%, 0.8%, 0.6%, 0.4%, 0.2%, 0.1%, etc.

[0047] Preferably, the single-layer rate of the graphene oxide is >98%, for example, it can be 98.1%, 98.2%, 98.3%, 98.4%, 98.5%, 98.6%, 98.7%, 98.8%, 98.9%, etc.

[0048] Preferably, the specific surface area of the graphene oxide is >1200m 2 / g, for example, it can be 1200m 2 / g, 1210m 2 / g, 1220m 2 / g, 1240m 2 / g, 1260m 2 / g, 1280m 2 / g, 1300m 2 / g, etc.

[0049] Preferably, the sheet layer thickness of the graphene oxide is 0.6-1.0nm, for example, it can be 0.6nm, 0.7nm, 0.8nm, 0.9nm, 1.0nm, etc.

[0050] Preferably, the sheet layer diameter of the graphene oxide is 500-5000nm, for example, it can be 500nm, 1000nm, 1500nm, 2000nm, 2500nm, 3000nm, 3500nm, 4000nm, 4500nm, 5000nm, etc.

[0051] Preferably, the pH value of the graphene oxide is 5-7, for example, it can be 5, 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, etc.

[0052] Preferably, the oscillation frequency of the first ultrasonic atomization spraying is 20-100kHz, for example, it can be 20kHz, 30kHz, 40kHz, 50kHz, 60kHz, 70kHz, 80kHz, 90kHz, 100kHz, etc., and further preferably 60kHz.

[0053] Preferably, the oscillation power of the first ultrasonic atomization spraying is 2-8W, for example, it can be 2W, 2.5W, 3W, 3.5W, 4W, 4.5W, 5W, 5.5W, 6W, 6.5W, 7W, 7.5W, 8W, etc., and further preferably 4W.

[0054] Preferably, the solution delivery rate of the first ultrasonic atomization spraying is 0.2-1.0 mL / min, for example, it can be 0.2 mL / min, 0.3 mL / min, 0.4 mL / min, 0.5 mL / min, 0.6 mL / min, 0.7 mL / min, 0.8 mL / min, 0.9 mL / min, 1.0 mL / min, etc., and further preferably 0.5 mL / min.

[0055] Preferably, the reciprocating movement speed of the spray head of the first ultrasonic atomization spraying is 3000-10000 mm / min, for example, it can be 3000 mm / min, 4000 mm / min, 5000 mm / min, 6000 mm / min, 7000 mm / min, 8000 mm / min, 9000 mm / min, 10000 mm / min, etc., and further preferably 6000 mm / min.

[0056] Preferably, the first ultrasonic atomization spraying forms the first contact layer by at least two times of spraying, for example, it can be 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 12 times, 14 times, 16 times, 18 times, 20 times, etc.

[0057] Preferably, during the first ultrasonic atomization spraying, the thickness of the contact layer formed by single spraying is 5-50 nm, for example, it can be 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc., and further preferably 25 nm.

[0058] Preferably, during the first ultrasonic atomization spraying, the total thickness of the first contact layer is 20-100 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc., and further preferably 50 nm.

[0059] Preferably, the oscillation frequency of the second ultrasonic atomization spraying is 20-100 kHz, for example, it can be 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz, 90 kHz, 100 kHz, etc., and further preferably 60 kHz.

[0060] Preferably, the oscillation power of the second ultrasonic atomization spraying is 2-8 W, for example, it can be 2 W, 2.5 W, 3 W, 3.5 W, 4 W, 4.5 W, 5 W, 5.5 W, 6 W, 6.5 W, 7 W, 7.5 W, 8 W, etc., and further preferably 6 W.

[0061] Preferably, the solution delivery rate of the second ultrasonic atomization spraying is 0.1-0.5 mL / min, for example, it can be 0.1 mL / min, 0.2 mL / min, 0.3 mL / min, 0.4 mL / min, 0.5 mL / min, etc., and further preferably 0.2 mL / min.

[0062] Preferably, the reciprocating speed of the spray head of the second ultrasonic atomization spraying is 3000-10000 mm / min, for example, it can be 3000 mm / min, 4000 mm / min, 5000 mm / min, 6000 mm / min, 7000 mm / min, 8000 mm / min, 9000 mm / min, 10000 mm / min, etc., and further preferably 6000 mm / min.

[0063] Preferably, the second contact layer is formed by at least two times of spraying in the second ultrasonic atomization spraying, for example, it can be 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 12 times, 14 times, 16 times, 18 times, 20 times, 30 times, 40 times, 50 times, 60 times, 100 times, 150 times, 200 times, 500 times, 1000 times, etc.

[0064] Preferably, the thickness of the contact layer formed by single spraying in the second ultrasonic atomization spraying is 5-20 nm, for example, it can be 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, etc., and further preferably 10 nm.

[0065] Preferably, the total thickness of the second contact layer in the second ultrasonic atomization spraying is 200-5000 nm, for example, it can be 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, 1200 nm, 1400 nm, 1600 nm, 1800 nm, 2000 nm, 2200 nm, 2500 nm, 3000 nm, 3200 nm, 3500 nm, 4000 nm, 4500 nm, 5000 nm, etc., and further preferably 500 nm.

[0066] Preferably, after the spraying is completed, a heat treatment is further performed at a temperature of 120-340°C (for example, it can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, etc.) for 0.1-1.0h (for example, it can be 0.1h, 0.2h, 0.3h, 0.4h, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, etc.).

[0067] In a second aspect, the present application provides a graphene oxide semiconductor thin film prepared by the method for preparing a graphene oxide semiconductor thin film with adjustable band gap as described in the first aspect.

[0068] Preferably, the photoexcitation band gap of the graphene oxide semiconductor thin film is 1.06-3.55eV.

[0069] Preferably, the conductivity of the graphene oxide semiconductor thin film at 40°C is 0.0204-0.3650S / cm.

[0070] Preferably, the conductivity of the graphene oxide semiconductor thin film at 120°C is 0.0564-0.6026S / cm.

[0071] In a third aspect, the present application provides a use of the graphene oxide semiconductor thin film as described in the second aspect in the preparation of a semiconductor element.

[0072] Further, the graphene oxide semiconductor thin film can be used in the preparation of PN junction, photoelectric element, temperature sensor, conductive layer, heat conductive layer, optical filter and other semiconductor elements.

[0073] Compared with the prior art, the present application has the following beneficial effects:

[0074] (1) In the method for preparing the graphene oxide semiconductor thin film of the present application, the unsaturation and functional group concentration of graphene oxide are regulated by using a heat treatment method. Compared with other methods for adjusting the band gap of graphene oxide, the heat treatment method is continuous, has high regulation accuracy and is easy to operate, and is suitable for regulating the band gap of a large-size graphene oxide semiconductor thin film.

[0075] (2) In the preparation method of the graphene oxide semiconductor thin film, the wettability angle of the graphene oxide solution on the surface of the quartz sheet is reduced, and the adsorption of the graphene oxide solution on the surface of the quartz sheet and the structural uniformity of the graphene oxide semiconductor thin film are improved by the method of performing plasma surface treatment on the surface of the quartz sheet and constructing a first contact layer on the surface of the quartz sheet.

[0076] (3) In the preparation method of the graphene oxide semiconductor thin film, the ultrasonic atomization spraying and synchronous heat treatment method is adopted, only the uppermost tens of nanometer thick graphene oxide is reduced each time, the generated gas can be smoothly dissipated, and the structural integrity and uniformity of the graphene oxide semiconductor thin film are not negatively affected. Through this method, graphene oxide layers are continuously stacked, and finally a graphene oxide semiconductor thin film with complete structure, uniform texture and thickness of hundreds of nanometers to microns can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0077] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0078] Figure 1 It is a schematic diagram of the structure of PN junction and the working mechanism of light emitting diode and photovoltaic cell.

[0079] Figure 2 It is a graph of the correlation between the band gap of graphene material and the ratio of oxygen and carbon atoms.

[0080] Figure 3 It is a schematic diagram of the appearance of the graphene oxide semiconductor thin film prepared in Example 1.

[0081] Figure 4 It is a schematic diagram of the appearance of the graphene oxide semiconductor thin film prepared in Comparative Example 1.

[0082] Figure 5 It is a schematic diagram of the appearance of the graphene oxide semiconductor thin film prepared in Comparative Example 5.

[0083] Figure 6 It is a graph of the ultraviolet-visible light absorption rate of the graphene oxide semiconductor thin film provided in Examples 1-6.

[0084] Figure 7 It is a graph of the conductivity change curve of the graphene oxide semiconductor thin film provided in Examples 1-6 in the range of 40-120℃. DETAILED DESCRIPTION

[0085] Unless otherwise defined, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any latent ambiguity, definitions provided herein take precedent over any dictionary or extrinsic definition. In this application, the use of "or" means "and / or" unless specifically stated otherwise, e.g., "comprising A or B" means "comprising A or B or both". Also, the use of "comprising" or "including" or "having" are not intended to exclude other

[0086] It should be noted that specific details are set forth in the following description in order to provide a thorough understanding of the application. However, the application can be practiced without many of the details described in this description, many of which are well known in the art. Therefore, the particular implementation described herein is not intended to limit the scope of the application.

[0087] The technical solutions of the present application will be described clearly and completely in connection with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of the present application.

[0088] The present application will be further described by the following examples. Unless otherwise specified, the materials in the examples are prepared according to the existing methods, or directly purchased from the market.

[0089] The parameters of raw materials used in the following examples and comparative examples are shown as follows:

[0090] I. Substrate: The thin film substrate material is high-purity quartz sheet with a purity of 99.9%, a thermal expansion coefficient of 2x10 -6 / K, a surface roughness of 5 nm, an electrical conductivity of 10 -14 S / cm, a length of 40 mm, a width of 20 mm, and a thickness of 1 mm; an absorption rate of visible light (wavelength 400-780 nm) of 6%, an absorption rate of near-infrared light (wavelength 780-2526 nm) of 8%, and an absorption rate of near-ultraviolet light (wavelength 300-400 nm) of 11%;

[0091] The surface of the quartz sheet is subjected to plasma surface treatment before spraying, the voltage of the plasma surface treatment is 6 kV, the treatment time is 150 s, the absolute pressure in the vacuum chamber is 200 Pa, and the radio frequency power is 360 W; the wetting angle of the graphene oxide solution on the surface of the treated quartz sheet is 14°.

[0092] II. Graphene oxide solution:

[0093] The graphene oxide stock solution is provided by Shenzhen Suiheng Technology Co., Ltd., wherein the concentration of the graphene oxide is 5 mg / mL, and the solvent is deionized water. The proportion of carbon element in the graphene oxide is 45-47%, the proportion of hydrogen element is <2%, the proportion of nitrogen element is <2%, the proportion of sulfur element is <1%, and the remaining elements are oxygen. The single-layer rate of the graphene oxide is >98%, the specific surface area is >1200 m 2 / g, the sheet thickness ranges from 0.6 to 1.0 nm, the sheet diameter ranges from 500 to 5000 nm, and the pH value is 5-7.

[0094] In the graphene oxide stock solution, a certain amount of ethanol is added to dilute the graphene oxide ethanol solution, so that the concentration of the graphene oxide in the diluted solution is 0.5 mg / mL.

[0095] Embodiment 1

[0096] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, and specifically includes the following steps:

[0097] S1, heat the high-purity quartz sheet to 105°C, and spray the above-mentioned 0.5 mg / mL graphene oxide solution to the surface of the pure quartz sheet to form a first contact layer at the heat treatment temperature (105°C) by ultrasonic atomization spraying;

[0098] The ultrasonic atomization spraying is set at a vibration frequency of 60 kHz and a vibration power of 4 W, the solution is propelled at a speed of 0.5 mL / min, and the nozzle reciprocates at a rate of 6000 mm / min.

[0099] The film thickness formed by single spraying is 25 nm, and the total thickness of the first contact layer is 50 nm by 2 times of spraying.

[0100] S2, heat the high-purity quartz sheet to 200°C, and continue to spray the above-mentioned 0.5 mg / mL graphene oxide solution to the surface of the first contact layer to form a second contact layer at the heat treatment temperature (200°C) by ultrasonic atomization spraying;

[0101] The ultrasonic atomization spraying is set at a vibration frequency of 60 kHz and a vibration power of 6 W, the solution is propelled at a speed of 0.2 mL / min, and the nozzle reciprocates at a rate of 6000 mm / min.

[0102] The film thickness formed by single spraying is 10 nm, and the total thickness of the second contact layer is 500 nm by 50 times of spraying.

[0103] S3, after the spraying is completed, the substrate is kept at a heat treatment temperature of 200 DEG C for 0.2h, and then naturally cooled, to obtain a graphene oxide semiconductor film.

[0104] Figure 3 A schematic diagram of the appearance of the graphene oxide semiconductor film prepared in Example 1 is shown. As shown in the figure, by continuously stacking graphene oxide layers in this way, a graphene oxide semiconductor film with a complete structure, uniform texture and a thickness of hundreds of nanometers to microns can be finally obtained. It is illustrated that in the above-mentioned graphene oxide semiconductor film preparation method, since the method of ultrasonic atomization spraying and simultaneous heat treatment is adopted, only the uppermost tens of nanometers of graphene oxide reacts each time, and the generated gas can be smoothly dissipated. Figure 3

[0105] Example 2

[0106] The present embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is only different from Example 1 in that in S2, the high-purity quartz sheet is heated to 160 DEG C, and the ultrasonic atomization spraying is performed at the heat treatment temperature (160 DEG C), and the other steps are completely consistent with Example 1.

[0107] Example 3

[0108] The present embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is only different from Example 1 in that in S2, the high-purity quartz sheet is heated to 180 DEG C, and the ultrasonic atomization spraying is performed at the heat treatment temperature (180 DEG C), and the other steps are completely consistent with Example 1.

[0109] Example 4

[0110] The present embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is only different from Example 1 in that in S2, the high-purity quartz sheet is heated to 225 DEG C, and the ultrasonic atomization spraying is performed at the heat treatment temperature (225 DEG C), and the other steps are completely consistent with Example 1.

[0111] Example 5

[0112] The present embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is only different from Example 1 in that in S2, the high-purity quartz sheet is heated to 260 DEG C, and the ultrasonic atomization spraying is performed at the heat treatment temperature (260 DEG C), and the other steps are completely consistent with Example 1.

[0113] Example 6

[0114] ​The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that high-purity quartz slices are heated to 300 DEG C in S2, and ultrasonic atomization spraying is performed at the heat treatment temperature (300 DEG C), and other steps are completely consistent with the embodiment 1.

[0115] Embodiment 7

[0116] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that high-purity quartz slices are heated to 80 DEG C in S1, and ultrasonic atomization spraying is performed at the heat treatment temperature (80 DEG C), and other steps are completely consistent with the embodiment 1.

[0117] Embodiment 8

[0118] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that high-purity quartz slices are heated to 120 DEG C in S1, and ultrasonic atomization spraying is performed at the heat treatment temperature (120 DEG C), and other steps are completely consistent with the embodiment 1.

[0119] Embodiment 9

[0120] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the oscillation frequency of ultrasonic atomization spraying is 20 kHz, the oscillation power is 2 W, the solution delivery rate is 0.2 mL / min, and the nozzle reciprocating movement speed is 3000 mm / min in S1, and other steps are completely consistent with the embodiment 1.

[0121] Embodiment 10

[0122] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the oscillation frequency of ultrasonic atomization spraying is 100 kHz, the oscillation power is 8 W, the solution delivery rate is 1.0 mL / min, and the nozzle reciprocating movement speed is 10000 mm / min in S1, and other steps are completely consistent with the embodiment 1.

[0123] Embodiment 11

[0124] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the film thickness formed by single spraying is 5 nm in the process of ultrasonic atomization spraying in S1, and a contact layer is formed by 10 times of spraying, and the total thickness of the first contact layer is 50 nm, and other steps are completely consistent with the embodiment 1.

[0125] Embodiment 12

[0126] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the film thickness formed by single spraying in the process of S1 ultrasonic atomization spraying is 20 nm; a contact layer is formed through 5 times of spraying, and the total thickness of the first contact layer is 100 nm; and other steps are completely consistent with the embodiment 1.

[0127] Embodiment 13

[0128] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the film thickness formed by single spraying in the process of S2 ultrasonic atomization spraying is 5 nm; a contact layer is formed through 40 times of spraying, and the total thickness of the first contact layer is 200 nm; and other steps are completely consistent with the embodiment 1.

[0129] Embodiment 14

[0130] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the film thickness formed by single spraying in the process of S2 ultrasonic atomization spraying is 20 nm; a contact layer is formed through 50 times of spraying, and the total thickness of the first contact layer is 1000 nm; and other steps are completely consistent with the embodiment 1.

[0131] Embodiment 15

[0132] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the film thickness formed by single spraying in the process of S2 ultrasonic atomization spraying is 5 nm; a contact layer is formed through 40 times of spraying, and the total thickness of the first contact layer is 200 nm; and other steps are completely consistent with the embodiment 1.

[0133] Embodiment 16

[0134] The embodiment provides a preparation method of a graphene oxide semiconductor film with adjustable band gap, which is different from the embodiment 1 only in that the film thickness formed by single spraying in the process of S2 ultrasonic atomization spraying is 20 nm; a contact layer is formed through 50 times of spraying, and the total thickness of the first contact layer is 1000 nm; and other steps are completely consistent with the embodiment 1.

[0135] Comparative Example 1

[0136] The comparative example provides a preparation method of a graphene oxide semiconductor film, and the preparation method specifically comprises the following steps.

[0137] S1. At 80°C, the above-mentioned 0.5 mg / mL graphene oxide solution is sprayed onto the surface of a pure quartz sheet to form a first contact layer using ultrasonic atomization spraying.

[0138] The ultrasonic atomization spraying was set with an oscillation frequency of 60kHz, an oscillation power of 4W, a solution propulsion speed of 0.5mL / min, and a nozzle reciprocating speed of 6000mm / min.

[0139] The film thickness formed by a single spraying is 10 nm; the contact layer is formed by five sprayings, and the total thickness of the first contact layer is 50 nm.

[0140] S2. At 80°C, the above-mentioned 0.5 mg / mL graphene oxide solution is sprayed onto the surface of the first contact layer to form a second contact layer by ultrasonic atomization spraying.

[0141] The ultrasonic atomization spraying was set with an oscillation frequency of 60kHz, an oscillation power of 4W, a solution propulsion speed of 0.5mL / min, and a nozzle reciprocating speed of 6000mm / min.

[0142] The film thickness formed by a single spray is 10 nm; the contact layer is formed by 50 sprays, and the total thickness of the second contact layer is 500 nm.

[0143] S3. After spraying, keep the substrate at a heat treatment temperature of 200℃ for 1 hour, and then let it cool naturally to obtain a graphene oxide semiconductor film.

[0144] Figure 4 This is a schematic diagram showing the appearance of the graphene oxide semiconductor film prepared in Comparative Example 1. Figure 4 As shown, due to the use of a preparation process involving spray coating followed by heat treatment, the water vapor, carbon dioxide, and other gases generated during the heat treatment process cause the film structure to expand and break, severely impairing the integrity, uniformity, and conductivity of the film. Furthermore, as shown in Example 1 (… Figure 3 ) and Comparative Example 1 ( Figure 4 The comparison shows that using spraying and simultaneous heat treatment is of great significance in ensuring the integrity and uniformity of graphene semiconductor films.

[0145] Comparative Example 2

[0146] This comparative example provides a method for preparing a graphene oxide semiconductor thin film, the preparation method specifically including the following steps:

[0147] S1, heat the high-purity quartz wafer to 100℃, and spray the above-mentioned 0.5 mg / mL graphene oxide solution onto the surface of the quartz wafer to form a first contact layer under ultrasonic atomization spraying under ultraviolet light with a peak wavelength of 295 nm at a power of 12 W;

[0148] The ultrasonic atomization spraying is set at a frequency of 60 kHz and a power of 4 W, the solution is propelled at a speed of 0.5 mL / min, and the spray head reciprocates at a speed of 6000 mm / min.

[0149] The film thickness formed by a single spraying is 10 nm, and the total thickness of the contact layer formed by 5 sprayings is 50 nm.

[0150] S2, continue to heat at 100℃, and continue to spray the above-mentioned 0.5 mg / mL graphene oxide solution onto the surface of the first contact layer to form a second contact layer under ultrasonic atomization spraying under ultraviolet light with a peak wavelength of 295 nm at a power of 12 W;

[0151] The ultrasonic atomization spraying is set at a frequency of 60 kHz and a power of 4 W, the solution is propelled at a speed of 0.5 mL / min, and the spray head reciprocates at a speed of 6000 mm / min.

[0152] The film thickness formed by a single spraying is 10 nm, and the total thickness of the contact layer formed by 5 sprayings is 500 nm.

[0153] S3, after the spraying is completed, the substrate is kept at 100℃ for 0.2 h under ultraviolet light with a peak wavelength of 295 nm at a power of 12 W, and then naturally cooled to obtain a graphene oxide semiconductor thin film.

[0154] Comparative Example 3

[0155] This comparative example provides a method for preparing a graphene oxide semiconductor thin film, which is different from Example 1 in that the temperature of the heat treatment in S2 is 110℃, and the other steps are completely consistent with Example 1.

[0156] Comparative Example 4

[0157] This comparative example provides a method for preparing a graphene oxide semiconductor thin film, which is different from Example 1 in that the temperature of the heat treatment in S2 is 350℃, and the other steps are completely consistent with Example 1.

[0158] Comparative Example 5

[0159] This comparative example provides a method for preparing a graphene oxide semiconductor thin film. The difference from Example 1 is that the heat treatment temperature in S1 is 200°C, while the other steps are completely the same as in Example 1.

[0160] Figure 5 This is a schematic diagram showing the appearance of the graphene oxide semiconductor film prepared in Comparative Example 5. Figure 5 As shown, the graphene oxide semiconductor film prepared in Comparative Example 1 is light brown rather than brownish-black, and its light absorption rate is significantly reduced. The main reason is that at 200℃, the graphene oxide droplets cannot effectively adhere to the highly smooth quartz sheet surface due to the Rytterbest effect, resulting in the graphene oxide semiconductor film thickness failing to reach the predetermined thickness.

[0161] From Example 1 ( Figure 3 ) and Comparative Example 5 ( Figure 5 The comparison shows that by controlling the heating temperature of the first contact layer and constructing a uniform first contact layer on the surface of the quartz sheet, it is helpful for graphene oxide droplets to adhere to the surface of the quartz sheet, which is beneficial for the subsequent stacking of graphene oxide semiconductor films.

[0162] Test Example 1

[0163] Test samples: graphene oxide semiconductor films provided in Examples 1-16 and graphene oxide semiconductor films provided in Comparative Examples 1-5.

[0164] Test method: (1) The ultraviolet-visible light absorption rate was tested under ultraviolet-visible light in the wavelength range of 200-800nm. The ultraviolet-visible light absorption curve is shown below. Figure 6 As shown. (2) Based on the UV-Vis absorption measurement results, the photoexcitation bandgap of Examples 1-6 was calculated. The calculation of the photoexcitation bandgap Eg of graphene oxide was based on Tauc bandgap formula 1:

[0165] ahv = B(hv - E) g ) m Formula 1

[0166] Where α is the light absorption coefficient, B is the linear relationship coefficient, hν is the incident photon energy, and since the charge carriers in graphene oxide are directly excited, m is taken as 1 / 2.

[0167] The photoexcitation bandgap widths obtained based on the above calculation method are shown in Table 1 below:

[0168] Table 1

[0169]

[0170]

[0171] From the test results of Table 1, it can be seen that the optical excitation band gap of the graphene oxide semiconductor film prepared by the method is between 1.06-3.55 eV.

[0172] It can be seen from the comparison between Example 1 and Comparative Example 2 that, compared with heat treatment, the main shortcomings of light treatment include: (1) the band gap of graphene oxide is affected by the illumination time of ultraviolet light, and in actual preparation, the band gap of the lower graphene oxide is often much lower than that of the upper graphene oxide due to the much longer illumination time of the lower graphene oxide, resulting in uneven band gap between the upper and lower graphene oxide; (2) the band gap of graphene oxide is affected by the wavelength of ultraviolet light, in order to strengthen the control of the band gap of graphene oxide, a single wavelength ultraviolet light source is needed, which greatly increases the cost of band gap control; (3) ultraviolet light source is harmful to human body, compared with heat treatment, light treatment needs to take additional protective measures.

[0173] (3) Test the conductivity in the temperature range of 40-120℃.

[0174] The test results are as follows Figure 7 and shown in Table 2:

[0175] Table 2

[0176]

[0177]

[0178] From the test results of Table 2, it can be seen that the measurement results of the electrical properties of Examples 1-6 show that the conductivity of Examples 1-6 at 40℃ is 0.0204-0.3650 S / cm, and the conductivity at 120℃ is 0.0564-0.6026 S / cm, and the conductivity decreases with the increase of heat treatment temperature and test temperature; the overall conductivity of the graphene oxide semiconductor film prepared by the preparation method is excellent, and can be used as a semiconductor element.

[0179] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a graphene oxide semiconductor thin film with an adjustable bandgap, characterized in that, The preparation method comprises the following steps: The substrate is first heated to a first heat treatment temperature, and the graphene oxide solution is first ultrasonic atomization sprayed to the surface of the substrate at the heat treatment temperature to form a first contact layer; wherein the first heat treatment temperature is a temperature 20-40℃ higher than the gasification point temperature of the organic solvent; Then the substrate is heated to a second heat treatment temperature, and the graphene oxide solution is second ultrasonic atomization sprayed to the surface of the first contact layer at the second heat treatment temperature to form a second contact layer; wherein the second heat treatment temperature is 120-340℃.

2. The method for preparing an adjustable bandgap graphene oxide semiconductor thin film according to claim 1, characterized in that, The substrate is a quartz sheet with a purity of >99%.

3. The method for preparing the graphene oxide semiconductor thin film with adjustable bandgap according to claim 2, characterized in that, The quartz flake has a thermal expansion coefficient < 7 x 10 -6 The quartz flake has an electrical conductivity < 10 -10 S / cm.

4. The method of claim 2, wherein the graphene oxide semiconductor thin film having an adjustable band gap is prepared by the steps of: The length of the quartz sheet is 10-100 mm; the width of the quartz sheet is 10-50 mm; the thickness of the quartz sheet is 0.5-1.5 mm; and the surface roughness of the quartz sheet is 5-10 nm.

5. The method for preparing an adjustable bandgap graphene oxide semiconductor thin film according to claim 2, characterized in that, The visible light transmission absorption rate of the quartz sheet is <10%; the near-infrared light transmission absorption rate of the quartz sheet is <10%; and the near-ultraviolet light transmission absorption rate of the quartz sheet is <20%.

6. The method for preparing an adjustable bandgap graphene oxide semiconductor thin film according to claim 1, characterized in that, The wetting angle of the graphene oxide solution on the surface of the quartz sheet is <30°.

7. The method for preparing an adjustable bandgap graphene oxide semiconductor thin film according to claim 1, characterized in that, The concentration of the graphene oxide solution is 0.1-1.0 mg / mL.

8. The method for preparing an adjustable bandgap graphene oxide semiconductor thin film according to claim 1, characterized in that, The graphene oxide solution comprises graphene oxide, water and an organic solvent.

9. The method for preparing an adjustable bandgap graphene oxide semiconductor thin film according to claim 8, characterized in that, The volume ratio of the water and the organic solvent is 1:(5-15).

10. The method for preparing a graphene oxide semiconductor thin film with adjustable bandgap according to claim 8 or 9, characterized in that, The organic solvent is selected from C1-C3 monohydric alcohol and / or C3-C5 monoketone.

11. The method for preparing a graphene oxide semiconductor thin film with adjustable bandgap according to claim 8, characterized in that, In the graphene oxide, the proportion of carbon element is 45-47%, the proportion of hydrogen element is <2%, the proportion of nitrogen element is <2%, the proportion of sulfur element is <1%, and the remaining elements are all oxygen, with the total content of all elements being 100%.

12. The method for preparing the graphene oxide semiconductor thin film with adjustable bandgap according to claim 8, characterized in that, The single layer rate of the graphene oxide is >98%, the specific surface area is >1200 m 2 / g, the sheet thickness is 0.6~1.0 nm, the sheet diameter is 500~5000 nm, and the pH value is 5~7.

13. The method for preparing a graphene oxide semiconductor thin film with adjustable bandgap according to claim 1, characterized in that, The oscillation frequency of the first ultrasonic atomization spraying is 20-100 kHz; the oscillation power is 2-8 W; the solution delivery rate is 0.2-1.0 mL / min; and the reciprocating movement speed of the spray head is 3000-10000 mm / min.

14. The method of claim 1, wherein the method further comprises: The first ultrasonic atomization spraying forms the first contact layer through at least two sprays; wherein the thickness of the contact layer formed by a single spray is 5-50 nm; and the total thickness of the first contact layer is 20-100 nm.

15. The method of claim 1, wherein the method further comprises: The oscillation frequency of the second ultrasonic atomization spraying is 20-100 kHz; the oscillation power is 2-8 W; the solution delivery rate is 0.1-0.5 mL / min; and the reciprocating movement speed of the spray head is 3000-10000 mm / min.

16. The method of claim 1, wherein the method further comprises: The second ultrasonic atomization spraying forms the second contact layer through at least two sprays; wherein the thickness of the contact layer formed by a single spray is 5-20 nm; and the total thickness of the second contact layer is 200-5000 nm.

17. The method of claim 1, wherein the method further comprises: After the spraying is completed, a heat treatment at a temperature of 120-340℃ for 0.1-1.0 h is further required.

18. A graphene oxide semiconductor thin film, characterized by, The graphene oxide semiconductor thin film is prepared by the preparation method of the graphene oxide semiconductor thin film with adjustable band gap as claimed in any one of claims 1-17.

19. The graphene oxide semiconductor film according to claim 18, wherein, The photoexcitation band gap of the graphene oxide semiconductor thin film is 1.06-3.55 eV.

20. The graphene oxide semiconductor thin film according to claim 18, wherein, The conductivity of the graphene oxide semiconductor thin film at 40 DEG C is 0.0204-0.3650 S / cm.

21. The graphene oxide semiconductor thin film according to claim 18, wherein, The conductivity of the graphene oxide semiconductor thin film at 120 DEG C is 0.0564-0.6026 S / cm.

22. Use of the graphene oxide semiconductor thin film according to any one of claims 18-21 in the preparation of a semiconductor element.

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