CN103165810A - Carbon-coated V-VI compound semiconductor nanosheet and preparation method thereof - Google Patents

Abstract

The invention discloses a carbon-coated class V-VI compound semiconductor nano sheet and a preparation method thereof, and relates to a topological insulator and a thermoelectric material and a preparation method thereof. The method solves the problems that the conventional preparation method for the class V-VI compound topological insulator is complex and cannot be used for preparing bulk materials, the surface of the topological insulator is instable, unsymmetrical and high in roughness and the electric conductivity and the Seebeck coefficient of the topological insulator serving as the thermoelectric material cannot be simultaneously improved. The carbon-coated class V-VI compound semiconductor nano sheet consists of a nano sheet matrix and a carbon layer coated on the surface of the nano sheet matrix. The amorphous carbon-coated class V-VI compound semiconductor nano sheet is prepared through a one-step hydrothermal method; and a grapheme-coated class V-VI compound semiconductor nano sheet is prepared through a two-step hydrothermal method. The surface of the prepared nano sheet is stable, symmetrical and low in roughness, and the electric conductivity and the Seebeck coefficient of the nano sheet can be simultaneously improved. The invention is applied in the field of preparation of topological insulators and thermoelectric materials.

Description

Carbon-coated V-VI compound semiconductor nanosheet and preparation method thereof

technical field

The invention relates to a topological insulator, a thermoelectric material and a preparation method thereof. the

Background technique

Topological insulators are a new class of materials with special quantum properties. Its special two-dimensional structure and strong spin-orbit coupling effect make it have an extraordinary electronic structure. Its bulk electronic structure is an insulator with an energy gap, while its surface is a metallic state without an energy gap. That is to break the concept of "metal" and "insulator" in the usual sense. It is internally insulated, but the interface has a spin-related metallic conductive channel. This means that topological insulators can separate electrons with different spin orientations, creating spin currents. It has long been discovered that electrons have both charge and spin motions, but in traditional circuits or semiconductor electronic devices, spin-up electrons and spin-down electrons move in the same direction, so that the spin current is canceled , only the charge flow (i.e. current) exists. This has led to the application of electronic devices for nearly a hundred years, only using the charge of the electron, while its spin has been ignored. On the surface of topological insulators, due to the effect of spin-orbit coupling, the regularity of electron motion is just like that of a car moving on a highway. Cars traveling forward and reverse travel on different roads without interfering with each other. Electrons in such an orderly motion state will not collide with each other, so the energy consumption is very low. the

With the rapid development of microelectronics technology, the integration of semiconductor chips is getting higher and higher. This has two negative effects. On the one hand, it is the power consumption of the chip and its related heat dissipation; on the other hand, it is the quantum effect caused by the reduction of the device scale. Because the energy consumed to change the electron spin state is much lower than the energy consumed to change the charge state, if we use the spin degree of freedom of the carrier in the semiconductor to realize the function of the existing semiconductor device, the problem of power consumption will be reduced. Easy to solve. Due to the electrical control properties of these surface magnetisms possessed by topological insulators, people are full of expectations for the manufacture of new types of computer chips and other components in the future, and hope that this will trigger a new round of revolution in future electronic technology. the

In addition, the surface states of topological insulators have distinctive characteristics, which are completely determined by the topology of the bulk electronic state of the material, determined by symmetry, and have nothing to do with the specific structure of the surface. Therefore, his existence is very stable, basically unaffected by impurities and disorder. Since the topological properties of non-Abelian particles are protected by symmetry from the decoherence of quantum states due to small perturbations, resulting in calculation errors, this makes topological insulators useful in quantum computing. the

Topological insulators are of great significance to the study of the fundamental physics of condensed matter. For example, topological insulators near a superconductor can produce excitons that satisfy non-Abelian (non-commutative) statistics—Malayona fermions. the

In 2009, some scientists predicted through theoretical calculations that V-VI compound semiconductor functional materials (Bi ₂ Te ₃ , Sb ₂ Te ₃ , Bi ₂ Se _{3 ,} etc.) are a new type of strong topological insulator material system. This type of topological insulator material has unique advantages: first, this type of material is pure chemical, very stable and easy to synthesize; second, there is only one Dirac point in the surface state of this type of material, which is the simplest strong topological insulator, This simplicity provides a good platform for the study of theoretical models; thirdly, it is also very attractive that the bulk energy gap of this material is very large, especially for Bi ₂ Se ₃ , which is about 0.13eV, far from Beyond the room temperature energy scale, this also means that it is possible to realize spintronic devices with low energy consumption at room temperature. At the same time, relevant experimental work has also made important progress, confirming the correctness of the theoretical prediction.

Although there are exciting predictions about topological insulators in theory, there are still two very basic problems that need to be solved urgently in current experiments: firstly, to prepare high-quality topological insulator materials, especially materials that can be used in practice; secondly, is an intrinsic property of the surface states of topological insulators confirmed in transport experiments. The preparation of materials will become the basis of all performance and application research. Since 2009, in response to the demand for research on topological insulators, people have started research on material preparation from both single crystal materials and thin films. There are the following main problems: 1. Since the topological insulator produces the effect on the surface of the material, the existing research is mainly on the preparation of single crystal materials and thin films, the manufacturing process is complicated, the cost is high, and only one single crystal or thin film can be studied. surface, so it is impossible to prepare bulk materials, which limits the device application of materials; 2. The surface is unstable: the surface of the prepared material will degrade when exposed to the atmosphere. Although the surface state of the topological insulator is theoretically robust, as long as there is It exists on the surface, but exposure to the atmosphere may cause surface oxidation, adsorption of water, etc., resulting in changes in the surface chemical potential, resulting in surface doping effects and the introduction of carriers, as well as the reduction of surface electron mobility, which can cause scattering The electron mobility of the surface state is smaller than that of the bulk electron; 3. Surface symmetry problem: when using a topological insulator thin film, due to the influence of the substrate, changing the symmetry of the structure will induce an asymmetric energy in the vertical direction of the thin film. The band is bent, resulting in different positions of the upper and lower surface Fermi levels in the energy band. 4. Surface roughness: The roughness of the surface will also cause the dispersion of surface states in space and the reduction of surface electron mobility. This requires that the surface of the film must be atomically smooth, resulting in high requirements for the preparation technology. the

As a new energy-saving and environmental protection technology, thermoelectric effect power generation is an energy conversion method that uses thermoelectric materials to directly convert temperature difference resources into electrical energy. Compared with the traditional method currently used, it does not need a working medium and operates directly and statically. Therefore, its equipment has no moving parts, which ensures that it is environmentally friendly, noiseless and highly reliable. Therefore, many equipment working at low and high temperatures (such as boilers, automobile engines, and liquefied natural gas storage and transportation tanks) can become their temperature difference providers. The key to improving the efficiency of thermoelectric conversion devices lies in the preparation of high-performance thermoelectric materials. The study of thermoelectric theory shows that the quality factor of thermoelectric materials is directly proportional to electrical conductivity and Seebeck coefficient, and inversely proportional to thermal conductivity. However, these three physical quantities are inherently related, and the conversion efficiency of the material cannot be improved by changing one of them alone, which is the main bottleneck restricting the application of thermoelectric materials. Therefore, in the current research, the main means to improve the thermoelectric performance of materials is to reduce the thermal conductivity of materials. But this approach has almost reached the limit of what is possible. In order to make thermoelectric materials reach the standard of practical application, we must find a way to improve the electrical conductivity and Seebeck coefficient at the same time. the

Contents of the invention

The present invention is to solve the complex preparation method of the existing V-VI compound topological insulator, the inability to prepare bulk materials, the surface instability, surface asymmetry, high surface roughness, and the inability to simultaneously conduct conductivity and Seebeck coefficient as thermoelectric materials. To improve the problem, a carbon-coated V-VI compound semiconductor nanosheet and a preparation method thereof are provided. the

The carbon-coated V-VI compound semiconductor nanosheet of the present invention is composed of a nanosheet-shaped substrate and a carbon layer coated on its surface; wherein, the materials of the nanosheet-shaped substrate are Bi ₂ Te ₃ , Sb ₂ Te _3. Bi ₂ Se ₃ , Sb ₂ Se ₃ , including magnetic elements doped with Fe, Cr, Co or Ni (eg, Bi _{2-x Fex} Te ₃ ), the thickness of which is less than 100nm, and the diameter is at the micron level; the said The carbon layer is made of amorphous carbon or graphene microsheets with a thickness of 1-12nm, and Ag, Fe, Cr, Co, Ni or Cu nanoparticles can be loaded on the outer surface.

The preparation method of the first carbon-coated V-VI group compound semiconductor nanosheet of the present invention is carried out according to the following steps:

1. Weigh 0.02-0.1g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02-0.1g of Na ₂ TeO ₃ powder, 1-5g of NaOH and 3-10g of glucose;

2. Add 5-10mL of deionized water to the raw materials weighed in step 1, stir to dissolve and mix, add deionized water to dilute to 20-40mL, then add 2-4mL of N ₂ H ₄ ·H ₂ O , transferred to a 50mL reactor, and reacted in an oven at 180-200°C for 5-8 hours to obtain a mixed solution;

3. Wash the reacted mixed solution with deionized water until the pH value is 7, then wash it with absolute ethanol, and finally dry it in vacuum at a temperature of 20-40°C to obtain an amorphous carbon-coated V-VI compound semiconductor Nanosheets. the

The preparation method of the second carbon-coated V-VI group compound semiconductor nanosheet of the present invention is carried out according to the following steps:

1. Weigh 0.02-0.05g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02-0.05g of Na ₂ TeO ₃ powder and 0.5-1.0g of NaOH;

2. Add 20-40mL of deionized water to the raw material weighed in step 1, stir and dissolve, add 2-4mL of N ₂ H ₄ ·H ₂ O, transfer to a 50mL reactor with a filling degree of 60% ～80%, react in an oven at 180～200°C for 5～8 hours to obtain a mixed solution;

3. Wash the reacted mixed solution with deionized water until the pH value is 7, then wash it with absolute ethanol, and finally dry it in vacuum at a temperature of 20-40° C. to obtain Sb ₂ Te ₃ nanosheets;

4. Weigh 0.002-0.003g of graphene oxide powder, add absolute ethanol and ultrasonically disperse for 15-30min, then add 0.02-0.05g of Sb ₂ Te ₃ nanosheets obtained in step 1, stir and add 3-6mL of Amine, react at 90-120°C for 1-3 hours to obtain a suspension;

5. Centrifuge the suspension obtained in step 4, and dry it in a vacuum at a temperature of 20-40° C. to obtain graphene-coated V-VI compound semiconductor nanosheets. the

The present invention includes the following beneficial effects:

1. The present invention uses a simple method to prepare carbon-coated V-VI compound semiconductor nanosheets, which makes it possible to prepare bulk materials due to the powerful protection of the interface;

2. The graphene-coated V-VI compound semiconductor nanosheets prepared by the present invention have good stability and prevent surface degradation;

3. The graphene-coated V-VI compound semiconductor nanosheet prepared by the present invention solves the problem of surface symmetry of the material. Since the upper and lower surfaces of the nanosheet are coated with carbon materials of the same thickness at the same time, the influence of the substrate is avoided. adverse effects caused by eccentricity;

4. The graphene-coated V-VI compound semiconductor nanosheet prepared by the present invention reduces the surface roughness of the material and avoids its adverse effects on the material performance;

5. The present invention uses different parts of the composite material to undertake the task of providing the electrical conductivity and the Seebeck coefficient, thereby breaking the inherent correlation between the three physical quantities that determine the thermoelectric properties of the material, and simultaneously increasing the electrical conductivity and the Seebeck coefficient of the material. the

Description of drawings

Fig. 1 is the structural representation of the carbon-coated V-VI compound semiconductor nanosheet prepared in Experiment 1;

Fig. 2 is the FESEM photo of the carbon-coated V-VI group compound semiconductor nanosheets prepared in test one;

Fig. 3 is the TEM image of the carbon-coated V-VI group compound semiconductor nanosheet prepared in test one;

Figure 4 is a graph showing the electrical conductivity of carbon-coated V-VI compound semiconductor nanosheets prepared in Experiment 1 and the electrical conductivity of uncoated Sb ₂ Te ₃ nanosheets as a function of temperature; where 1 is Sb ₂ Te ₃ nanosheets Variation curve with temperature, 2 is the conductivity curve with temperature variation of the carbon-coated V-VI compound semiconductor nanosheets prepared in Experiment 1;

Figure 5 is a graph showing the Seebeck coefficient of carbon-coated V-VI compound semiconductor nanosheets prepared in Experiment 1 and the Seebeck coefficient of uncoated Sb ₂ Te ₃ nanosheets as a function of temperature; where 1 is Sb ₂ Te ₃ nanosheets 2 is a graph of the Seebeck coefficient varying with temperature, and 2 is a graph of the Seebeck coefficient varying with temperature of the carbon-coated V-VI compound semiconductor nanosheets prepared in Experiment 1.

Detailed ways

Specific embodiment 1: The carbon-coated V-VI compound semiconductor nanosheet of this embodiment is composed of a nanosheet-shaped substrate and a carbon layer coated on its surface; wherein, the material of the nanosheet-shaped substrate is _Bi2 Te ₃ , Sb ₂ Te ₃ , Bi ₂ Se ₃ , Sb ₂ Se ₃ , including magnetic elements doped with Fe, Cr, Co or Ni, the thickness is less than 100nm, and the diameter is at the micron level; the material of the carbon layer is no Shaped carbon or graphene microsheets, with a thickness of 1-12nm, and Ag, Fe, Cr, Co, Ni or Cu nanoparticles can be loaded on the outer surface.

Specific implementation mode two: the preparation method of the carbon-coated V-VI group compound semiconductor nanosheet of the present embodiment is carried out according to the following steps:

1. Weigh 0.02-0.1g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02-0.1g of Na ₂ TeO ₃ powder, 1-5g of NaOH and 3-10g of glucose;

2. Add 5-10mL of deionized water to the raw materials weighed in step 1, stir to dissolve and mix, add deionized water to dilute to 20-40mL, then add 2-4mL of N ₂ H ₄ ·H ₂ O , transferred to a 50mL reactor, and reacted in an oven at 180-200°C for 5-8 hours to obtain a mixed solution;

3. Wash the reacted mixed solution with deionized water until the pH value is 7, then wash it with absolute ethanol, and finally dry it in vacuum at a temperature of 20-40°C to obtain an amorphous carbon-coated V-VI compound semiconductor Nanosheets. the

This embodiment includes the following beneficial effects:

1. This embodiment uses a simple method to prepare carbon-coated V-VI compound semiconductor nanosheets, which makes it possible to prepare bulk materials due to the strong protection of the interface;

2. The carbon-coated V-VI compound semiconductor nanosheets prepared in this embodiment have good stability and prevent surface degradation;

3. The carbon-coated V-VI compound semiconductor nanosheets prepared in this embodiment solve the problem of material surface symmetry. Since the upper and lower surfaces of the nanosheets are coated with carbon materials of the same thickness at the same time, the influence of the substrate is avoided. adverse effects caused by eccentricity;

4. The carbon-coated V-VI compound semiconductor nanosheets prepared in this embodiment reduce the surface roughness of the material and avoid its adverse effects on the material performance;

5. The present invention uses different parts of the composite material to undertake the task of providing the electrical conductivity and the Seebeck coefficient, thereby breaking the inherent correlation between the three physical quantities that determine the thermoelectric properties of the material, and simultaneously increasing the electrical conductivity and the Seebeck coefficient of the material. the

Specific embodiment 3: The difference between this embodiment and specific embodiment 2 is that in step 1, 0.02g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O and 0.02g of Na ₂ TeO ₃ powder are weighed, 1 g of NaOH and 3 g of glucose. Others are the same as in the second embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 2 or 3 is that 2 mL of N ₂ H ₄ ·H ₂ O is added in Step 2. Others are the same as the second or third specific embodiment.

Embodiment 5: This embodiment is different from Embodiment 2 to Embodiment 4 in that: in step 2, the reaction is carried out in an oven at 180° C. for 5 hours. Others are the same as one of the second to fourth specific embodiments. the

Specific embodiment six: The preparation method of the carbon-coated V-VI compound semiconductor nanosheet of this embodiment is carried out in the following steps:

1. Weigh 0.02-0.05g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02-0.05g of Na ₂ TeO ₃ powder and 0.5-1.0g of NaOH;

2. Add 20-40mL of deionized water to the raw material weighed in step 1, stir and dissolve, add 2-4mL of N ₂ H ₄ ·H ₂ O, transfer to a 50mL reactor with a filling degree of 60% ～80%, react in an oven at 180～200°C for 5～8 hours to obtain a mixed solution;

3. Wash the reacted mixed solution with deionized water until the pH value is 7, then wash it with absolute ethanol, and finally dry it in vacuum at a temperature of 20-40° C. to obtain Sb ₂ Te ₃ nanosheets;

4. Weigh 0.002-0.003g of graphene oxide powder, add absolute ethanol and ultrasonically disperse for 15-30min, then add 0.02-0.05g of Sb ₂ Te ₃ nanosheets obtained in step 1, stir and add 3-6mL of Amine, react at 90-120°C for 1-3 hours to obtain a suspension;

5. Centrifuge the suspension obtained in step 4, and dry it in a vacuum at a temperature of 20-40° C. to obtain graphene-coated V-VI compound semiconductor nanosheets. the

Embodiment 7: The difference between this embodiment and Embodiment 6 is that in step 1, 0.02g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02g of Na ₂ TeO ₃ powder and 1.0 g of NaOH. Others are the same as in the sixth embodiment.

Embodiment 8: This embodiment is different from Embodiment 6 or 7 in that: 0.002g of graphene oxide powder is weighed in Step 4. Others are the same as in Embodiment 6 or 7. the

Embodiment 9: This embodiment is different from Embodiment 6 to Embodiment 8 in that: in step 4, absolute ethanol is added for ultrasonic dispersion for 15 minutes. Others are the same as one of the sixth to eighth specific embodiments. the

Embodiment 10: This embodiment is different from Embodiment 6 to Embodiment 9 in that: in step 4, 3 mL of hydrazine is added after stirring, and reacted at 95° C. for 2 h. Others are the same as one of the sixth to ninth specific embodiments. the

Verify beneficial effect of the present invention by following test:

Experiment 1: The preparation method of carbon-coated V-VI compound semiconductor nanosheets in this experiment is realized according to the following steps:

1. Weigh 0.02g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02g of Na ₂ TeO ₃ powder, 1g of NaOH and 3g of glucose;

2. Add 5mL of deionized water to the raw materials weighed in step 1, stir to dissolve and mix, add deionized water to dilute to 30mL, then add 2mL of N ₂ H ₄ ·H ₂ O, transfer to 50mL In the reaction kettle, react in an oven at 180°C for 5 hours to obtain a mixed solution;

3. Wash the reacted mixed solution with deionized water until the pH value is 7, then wash with absolute ethanol, and finally dry it in vacuum at a temperature of 40°C to obtain amorphous carbon-coated V-VI compound semiconductor nanosheets . the

In this experiment, a simple method was used to prepare carbon-coated V-VI compound semiconductor nanosheets. Due to the strong protection of the interface, it is possible to prepare bulk materials. the

The schematic diagram of the structure of the carbon-coated V-VI compound semiconductor nanosheets prepared in this experiment is shown in Figure 1. It can be seen from Figure 1 that the carbon layer wraps the nanosheet-like body inside. the

The FESEM photo of the carbon-coated V-VI compound semiconductor nanosheets prepared in this test is shown in Figure 2. It can be seen from Figure 2 that there is a curly film-like substance in the FESEM image;

The TEM image of the carbon-coated V-VI compound semiconductor nanosheets prepared in this experiment is shown in Figure 3. It can be seen from Figure 3 that the edge of the broken sheet supports the membrane;

It can be concluded from Figure 2 and Figure 3 that the amorphous C film is completely covered. the

The electrical conductivity of the carbon-coated V-VI compound semiconductor nanosheets prepared in this experiment and the electrical conductivity of the Sb ₂ Te ₃ nanosheets as a function of temperature are shown in Figure 4, where 1 is the Sb ₂ Te ₃ nanosheets The temperature change curve, 2 is the conductivity curve of the carbon-coated V-VI group compound semiconductor nanosheets prepared in this test as a function of temperature. As can be seen from Figure 4, the carbon-coated V-VI group compound prepared in this test The conductivity of semiconductor nanosheets is orders of magnitude higher than that of Sb ₂ Te ₃ nanosheets;

The Seebeck coefficient of the carbon-coated V-VI compound semiconductor nanosheets prepared in this experiment and the Seebeck coefficient of the Sb ₂ Te ₃ nanosheets as a function of temperature are shown in Figure 5, where 1 is the Sb ₂ Te ₃ nanosheets Seebeck coefficient curves with temperature, 2 is the Seebeck coefficient curves with temperature for the carbon-coated V-VI compound semiconductor nanosheets prepared in this test, as can be seen from Figure 5, the carbon-coated V-VI compound semiconductor nanosheets prepared in this test Compared with Sb ₂ Te ₃ nanosheets, the Seebeck coefficient of group VI compound semiconductor nanosheets is significantly improved;

It can be concluded from Figure 4 and Figure 5 that the electrical conductivity and Seebeck coefficient of the carbon-coated V-VI compound semiconductor nanosheets prepared in this experiment increase simultaneously. the

Experiment 2: The preparation method of carbon-coated V-VI compound semiconductor nanosheets in this experiment is realized according to the following steps:

1. Weigh 0.02g of K(SbO)C ₄ H ₄ O ₆ ·0.5H ₂ O, 0.02g of Na ₂ TeO ₃ powder and 1.0g of NaOH;

2. Add 30mL of deionized water to the raw material weighed in step 1, stir and dissolve, add 2mL of N ₂ H ₄ ·H ₂ O, transfer to a 50mL reactor with a filling degree of 80%, and store at 180°C React in oven for 5h to obtain mixed solution;

3. Wash the reacted mixed solution with deionized water until the pH value is 7, then wash it with absolute ethanol, and finally dry it in vacuum at a temperature of 40° C. to obtain Sb ₂ Te ₃ nanosheets;

4. Weigh 0.002g of graphene oxide powder, add absolute ethanol and ultrasonically disperse for 15min, add 0.02g of Sb ₂ Te ₃ nanosheets obtained in step 1, add 3mL of hydrazine after stirring, and react at 95°C for 2h to obtain suspension;

5. Centrifuge the suspension obtained in step 4, and dry it in a vacuum at a temperature of 40° C. to obtain graphene-coated V-VI compound semiconductor nanosheets. the

The graphene-coated V-VI compound semiconductor nanosheets prepared in this experiment have good stability and prevent surface degradation. the

The graphene-coated V-VI compound semiconductor nanosheets prepared in this experiment solved the problem of material surface symmetry. Since the upper and lower surfaces of the nanosheets were coated with carbon materials of the same thickness at the same time, the influence of the substrate was avoided. Adverse effects of eccentric action. the

The graphene-coated V-VI compound semiconductor nanosheets prepared in this experiment can reduce the surface roughness of the material and avoid its adverse effects on the material properties. the

Claims (10)

1. carbon coats the group Ⅴ-Ⅵ compound semiconductor nanometer sheet, it is characterized in that carbon coating group Ⅴ-Ⅵ compound semiconductor nanometer sheet by the nano-sheet matrix and be coated on its surperficial carbon-coating forming; Wherein, the material of described nano-sheet matrix is Bi ₂Te ₃, Sb ₂Te ₃, Bi ₂Se ₃, comprising doped F e, Cr, Co or Ni magnetic element, its thickness is less than 100nm, and diameter is in micron level; The material of described carbon-coating is agraphitic carbon or Graphene microplate, and thickness is 1～12nm, and can be at its outer surface loaded Ag, Fe, Cr, Co, Ni or Cu metal nanoparticle.

2. carbon coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that carbon coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method and carries out according to the following steps:

One, take K (SbO) C of 0.02～0.1g ₄H ₄O ₆0.5H ₂O, the Na of 0.02～0.1g ₂TeO ₃Powder, the NaOH of 1～5g and the glucose of 3～10g;

Two, add respectively the deionized water of 5～10mL in the raw material that takes to step 1, mix after stirring and dissolving, and add deionized water and be diluted to 20～40mL, then add the N of 2～4mL ₂H ₄H ₂O is transferred in the reactor of 50mL specification, reacts 5～8h in 180～200 ℃ of baking ovens, obtains mixed liquor;

Three, with reacted mixed liquor with deionized water wash to the pH value be 7, then use absolute ethanol washing, be 20～40 ℃ of vacuum dryings in temperature at last, obtain agraphitic carbon and coat the group Ⅴ-Ⅵ compound semiconductor nanometer sheet.

3. carbon according to claim 2 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that taking in step 1 K (SbO) C of 0.02g ₄H ₄O ₆0.5H ₂O, the Na of 0.02g ₂TeO ₃Powder, the NaOH of 1g and the glucose of 3g.

4. carbon according to claim 2 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that adding in step 2 the N of 2mL ₂H ₄H ₂O。

5. carbon according to claim 2 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that reacting 5h in step 2 in 180 ℃ of baking ovens.

6. carbon coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that the preparation method of carbon coating group Ⅴ-Ⅵ compound semiconductor nanometer sheet carries out according to the following steps:

One, take K (SbO) C of 0.02～0.05g ₄H ₄O ₆0.5H ₂O, the Na of 0.02～0.05g ₂TeO ₃The NaOH of powder and 0.5～1.0g;

Two, the deionized water that adds 20～40mL in the raw material that takes to step 1 adds the N of 2～4mL after stirring and dissolving ₂H ₄H ₂O is transferred in the reactor of 50mL specification, and compactedness is 60%～80%, reacts 5～8h in 180～200 ℃ of baking ovens, obtains mixed liquor;

Three, with reacted mixed liquor with deionized water wash to the pH value be 7, then use absolute ethanol washing, be 20～40 ℃ of vacuum dryings in temperature at last, obtain Sb ₂Te ₃Nanometer sheet;

Four, take the graphene oxide powder of 0.002～0.003g, after adding the ultrasonic dispersion 15～30min of absolute ethyl alcohol, the Sb that adds the step 1 of 0.02～0.05g to obtain ₂Te ₃Nanometer sheet adds the diamine of 3～6mL after stirring, 90～120 ℃ of reaction 1～3h obtain suspension-turbid liquid;

Five, the suspension-turbid liquid centrifugation that step 4 is obtained is to dry in 20～40 ℃ of vacuum in temperature, obtains graphene coated group Ⅴ-Ⅵ compound semiconductor nanometer sheet.

7. carbon according to claim 6 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that taking in step 1 K (SbO) C of 0.02g ₄H ₄O ₆0.5H ₂O, the Na of 0.02g ₂TeO ₃The NaOH of powder and 1.0g.

8. carbon according to claim 6 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that taking in step 4 the graphene oxide powder of 0.002g.

9. carbon according to claim 6 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, it is characterized in that adding in step 4 the ultrasonic dispersion of absolute ethyl alcohol 15min.

10. carbon according to claim 6 coats group Ⅴ-Ⅵ compound semiconductor nanometer sheet preparation method, adds the diamine of 3mL after it is characterized in that stirring in step 4,95 ℃ of reaction 2h.

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