Method for producing graphene film on substrate

FIELD: chemistry.

SUBSTANCE: substrate - a X-cut-off of piezoelectric crystal, e.g., La3Ga5.5Ta0.5O14, with planes (110) parallel to the crystal surface is placed into a quartz reactor. The reactor is pumped out to 10-3-10-8 Torr and heated up to 900-1450°C. The reactor then filled with carbon gases, e.g. acetylene, methane or ethylene, to achieve pressure of 10-10-1 Torr. After 15-100 min. the reactor is pumped out again to achieve pressure of 3·10-6 Torr while cooling it down to the room temperature.

EFFECT: process simplification, temperature reduction, production of uniform high-quality graphene films.

5 cl, 2 dwg, 3 ex

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to field of nanotechnologies and can be used for obtaining composite materials with high electric and heat conductivity, additives to concretes and ceramics, sorbents, catalysts. Carbon-containing material is evaporated in volume thermal plasma and condensed on target surface 9 and internal surface of collector 7. Plasma generator 3, which includes coaxially located electrodes: rod cathode 4 and nozzle-shaped output anode 5, are used. Gaseous carbon-containing material 6 is supplied with plasma-forming gas through vortex chamber with channels 2 and selected from the group, consisting of methane, propane, and butane. Bottom of collector is made with hole 8 for gas flow to pass.

EFFECT: invention makes it possible to reduce energy consumption of the process, extend types of applied hydrocarbon raw material, simplify device construction and provide continuity of the process and its high productivity.

2 dwg, 3 ex

FIELD: nanotechnologies.

SUBSTANCE: inventions relate to nanotechnology and may be used to manufacture catalysts and sorbents. Graphene pumice contains graphenes arranged in parallel at distances of more than 0.335 nm, and amorphous carbon as a binder at their edges, with the graphene-binder ratio from 1:0.1 to 1:1 by mass. The specific area of the surface is more than 1000 m2/g. The absolute hardness is 1 unit by the Mohs scale and less, specific density is 0.008-0.3 g/cm3 for solids, loose specific density of 0.005-0.25 g/cm3 for granules. The composition is produced by burning of a homogeneous powder mix of graphite oxide, unstable organic material and organic and inorganic metal salts with the moisture of all components of 10-15% in a heat-resistant open or tight mould. The source material for the binder is represented by chemical compounds capable of being in a liquid state up to 180°C, not soaking the graphite/graphene surface and damaged at a temperature of not more than 800°C. Graphene pumice is activated by restoration in hydrogen at 400-450°C and pressure of 0.05-0.11 MPa for 10-30 min or in methane at 800-950°C for at least 1 hour at atmospheric pressure with subsequent cooling.

EFFECT: produced sorbents make it possible to multiply increase the capacity of reservoirs for the storage and transportation of natural gas.

15 cl, 8 dwg, 2 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: graphite-containing component is mixed with a kaolin-based filling agent, dry mixing with simultaneous dispersion successively in a drum and centrifugal mixers is carried out. After that, a magnetised water solution of an alumoborophosphate concentrate, containing a surface-active substance, is introduced, and a wet batch in a screw mixer is carried out. After that, the obtained mass is processed in a tribochemical disperser under conditions of vacuuming and all-around compression to a pressure of 5-20 MPa. The tribochemical disperser includes a hermetic hollow cylindrical case 40, which has flanges 41 and 42 on butt ends, a permeable piston 44 with a rod 45, a drive 46 of reciprocating movement, means for the cavity vacuuming 43, two vacuum gate valves 471 and 472. The piston 44 represents a packet of adjoining each other pairs of metal nets which have the different cell size, located between two protective grids 445. The products are moulded from processed mass with their further thermal processing.

EFFECT: reproducibility of specific electric resistance in the products is provided, with the nanocomposite mass acquiring isotropic properties and ductility.

20 cl, 4 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: first, particles of thermally expanded graphite are obtained by heating particles of hydrolysed graphite nitrate with specific melt energy equal or higher than 4.7 kJ/g in the atmosphere of products of combustion of liquid or gaseous fuel in air with the coefficient of air excess counted per fuel λ=0.8-1.1. Obtained thermally expanded graphite is compacted to the seeming density from 0.03 to 0.1 g/cm3 by rolling or uniaxial pressing. After that, the material is cut into measured blanks. At least, two measured blanks are subjected to joint compression with obtaining a monolith material. The finished low-density material is made in the form of long-measuring product up to 1500 mm wide.

EFFECT: invention makes it possible to obtain the low-density heat-conducting material, possessing high bending strength and elasticity modulus and characterised by the absence of acidic corrosion-active additives.

10 cl, 3 ex

FIELD: chemistry.

SUBSTANCE: apparatus for producing thermally expanded graphite includes a feeding device 1, a circular waveguide 6, a storage hopper 19, a device for feeding blow-down carbon dioxide gas or air, magnetron generators, a belt conveyor with lower 2 and upper 3 belts formers 4 and 5. The circular waveguide 6 is provided with gas valves 15, longitudinal slits 14, communication windows 11 with insulating quartz inserts 12, insulating quartz rings 7 and 16 and is divided into sections having horn radiators 9 and 10. A layer of oxidised graphite undergoes microwave treatment for 0.1-0.5 s with power which provides temperature of 1500-1800°C, which is then lowered to provide temperature of 500-1000°C for 3-10 s.

EFFECT: high chemical purity and specific surface area and low packed density of thermally expanded graphite.

4 cl, 1 dwg

FIELD: nanotechnology.

SUBSTANCE: invention relates to nanotechnology and is intended for use in creation of modern thin-film semiconductor devices and structures of nanoelectronics. In the method of production of fluorographene layer the layer of desired thickness is separated from the volume graphite and is placed on the substrate. Then a fluorination operation is carried out using hydrofluoric acid under conditions enabling to obtain fluorographene layers with thickness up to 10-15 nm. At that the silicon substrate is used. On its working surface a silicon oxide layer can previously be grown. Fluorination is carried out in the aqueous solution of hydrofluoric acid with the content of 3-7% HF with the treatment duration up to 30 minutes, but not less than tcr, where the conductivity of fluorinated layers is changed. At that, when fluorination the temperatures up to 60°C are used.

EFFECT: improvement of quality of fluorographene layers is achieved, reduction of defectiveness, reduction of duration of the process, increase in ecological compatibility.

6 cl, 2 dwg

FIELD: electricity.

SUBSTANCE: invention is referred to electronic graphene device. Flexible and stretchable translucent electronic device contains the first graphene electrode, the second graphene electrode, graphene semiconductor and control graphene electrode located between the first and second graphene electrodes and being in contact with graphene semiconductor. Each of the above electrodes has porous graphene layer with a number of pores, at that each of the above electrodes has porous graphene layer and power supply source. Graphene semiconductor, the first and second graphene electrodes are configured so that current from power supply source between the first location at the first graphene electrode and the second location at the second graphene electrode sets difference of potentials between the first and second locations and this difference of potentials remains permanent when the first or second location changes.

EFFECT: improving charge-carrier mobility, ensuring ballistic transport, increasing current density and specific conductivity and possibility to control electric performance of the device.

15 cl, 3 dwg

FIELD: chemistry.

SUBSTANCE: claimed is carbon-containing material, obtained by pyrolysis of xarogel from hydrophilic polymer of polyhydroxybenzol/formaldehyde type and nitrogen-containing latex. Polymer and latex are co-crosslinked. Material represents carbon monolith, containing from 0.1 to 20% of graphite by weight of total material weight. Material contains system of pores, at least, 10% of which are mesopores, with pore volume constituting from 0.4 to 1 cm3/g. Material is characterised by presence of, at least, 3 successive characteristic peaks in the spectrum of X-ray diffraction. Claimed are: method of material obtaining and gel for its obtaining. Claimed material is used for production of electrodes and as filling agent in production of electric current-conducting components.

EFFECT: obtaining material with controlled porosity and reduction of material resistivity.

14 cl, 2 dwg, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention can be used in making high-heat areas of structures subjected to aggressive oxidative media. A graphite workpiece is subjected to vacuum embedding with high-temperature coal-tar pitch at temperature higher than the melting point of the pitch. Simultaneous saturation and carbonisation is then carried out at pressure of (80-105) MPa at temperature (700-750)°C, while maintaining said pressure and temperature for at least 4 hours and high-temperature vacuum treatment is carried out while maintaining temperature of (2100-2300)°C for at least half an hour.

EFFECT: high density and strength of the obtained material while still enabling the manufacture of large components from said material.

5 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to electronics and nanotechnology and cab be used in production of composite containing laminar graphite- and molybdenum sulphide-based materials. TEG or oxidised graphite and thiomolybdate are used as initial compounds. Note here that thiomolybdate is decomposed in the mix with TEG or oxidised graphite at heating or subjected to decomposition in solution with acid medium. Formed product containing TEG or oxidised graphite and precursor of molybdenum sulphide are flushed and heated in vacuum to 350-1000°C to obtain composite including molybdenum sulphide on graphite layers pile of composition MoxSy, where x=1-3, y=2-4. Note also that TEG or oxidised graphite are pre-dispersed while molybdenum precursor represents molybdenum tri-sulphide.

EFFECT: possibility to vary size, morphology and phase composition of nanoparticles on graphite surface.

4 dwg, 5 ex

FIELD: measurement equipment.

SUBSTANCE: method for determining a range of sizes of suspended nanoparticles consists in passage of gas (mixture of gases) containing analysed particles, through diffusion batteries of a meshed type and their introduction to supersaturated vapours of a low-volatile enlarging substance. Then, lighting of a flux of particles with a light beam and recording of parameters of light signals shaped by enlarged particles at their flying through the pointed-out area of the flux is performed. In order to improve accuracy of determination of the range of sizes, the main flux is separated into six parallel fluxes. With that, five of them are passed through five diffusion batteries with a different slip, and one of them is passed directly. Then, these fluxes pass through six devices of condensation growth and then to a field of vision of a charge-coupled device matrix and the obtained six areas of images of enlarged fluxes of particles are transmitted to a computer for an analysis of their range of sizes. Unlike known ones, the method allows performing simultaneous processing by means of a computer of six images of enlarged particles, which characterise different dimensional ranges of nanoparticles.

EFFECT: reducing the time required for measurements and improving their accuracy.

1 dwg

FIELD: physics.

SUBSTANCE: semiconductor structure for photo converting and light emitting devices consists of semiconductor substrate (1) with face surface misaligned from plane (100) through (0.5-10) degrees and at least one p-n junction (2) including at least one active semiconductor ply (3) arranged between two barrier plies (4) with inhibited zone width Eg0. Active semiconductor ply (3) consists of 1st and 2nd type spatial areas (5, 6) abutting of barrier plies (3) and alternating in the plane of active semiconductor ply (3). 1st type spatial areas (5) feature inhibited zone width Eg1 < Eg0, while 2nd type areas have inhibited zone width Eg2 < Eg1.

EFFECT: higher efficiency owing to increased photo flux and higher level of photo generation and charge carrier separation, higher probability of photon generation and lower probability of radiation-free recombination.

11 cl, 11 dwg, 5 ex

FIELD: chemistry.

SUBSTANCE: first step includes obtaining low-hydroxylated insoluble fullerenols by reacting concentrated fullerene solution in o-xylene with aqueous ammonia solution in the presence of a tetrabutylammonium hydroxide phase-transfer catalyst at 35-40°C. At the second step, the obtained low-hydroxylated insoluble fullerenols are hydroxylated to transform them into a water-soluble form by mixing with 6-15% aqueous hydrogen peroxide solution and heating for 4-5 hours at 65°C. Water-soluble fullerenols are then precipitated from an alcohol-containing solution.

EFFECT: simplifying the method while preserving quality characteristics and full extraction of the end product.

2 cl, 1 dwg, 4 tbl, 3 ex

FIELD: medicine, pharmaceutics.

SUBSTANCE: invention refers to pharmaceutical industry, namely to selenium nanocomposites of natural hepatotrophic galactose-containing polysaccharide matrixes, representing water-soluble orange-red powders containing zerovalent selenium (Se0) nanoparticles sized 1-100 nm in the quantitative content of 0.5 - 60 wt %, possessing antioxidant activity for treating and preventing redox-related pathologies, particularly for treating toxic liver damage, to a method for producing and to an antioxidant agent containing the above nanocomposites.

EFFECT: invention provides the targeted agent delivery to liver cells, as well as higher agent accessibility and lower toxic action of selenium.

7 cl, 11 ex, 4 tbl

FIELD: physics.

SUBSTANCE: method includes forming a near-field mask on the surface of a dielectric substrate and irradiating the obtained structure with a femtosecond laser pulse. The laser radiation is first passed through a nonlinear optical crystal with a coefficient of transformation into a second harmonic equal to 5-7%. The dielectric substrate coated with the near-field mask is irradiated with the obtained bichromatic femtosecond pulse with energy density in the range of 25-40 mJ/cm2, which is less than the laser radiation energy density normally used in similar nanopatterning.

EFFECT: high resolution and low laser radiation energy consumption.

6 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method for hydroconversion of heavy oil fractions - feed stock, the method including a zero step and subsequent N steps. The zero step includes feeding, into a reactor, material, a catalyst precursor - aqueous solution of a Mo (VI) salt or salts of Mo and Ni, and hydrogen at pressure of 4-9 MPa under normal conditions; reacting the material and hydrogen at 420-450°C in the presence of a precursor of a suspended nanosize molybdenum or molybdenum-nickel catalyst formed in the reactor; atmospheric or atmospheric-vacuum distillation of the hydrogenation product; removing the low-boiling fraction with a boiling point not higher than 500°C as a product and returning the high-boiling fraction or part thereof into the reactor. The next steps include feeding, into the reactor, material, a catalyst precursor, the returned part of the high-boiling fraction and hydrogen; reaction thereof; said atmospheric distillation of the hydrogenation product; removing the low-boiling fraction as a product; returning part of the high-boiling fraction into the reactor; burning at 1000-1300°C or gasification of the remaining part of the high-boiling fraction, after which trapped ash-slag residues are subjected to further oxidising burning at 800-900°C and the obtained ash product, which is carbon-free, is used to regenerate the catalyst precursor and produce an industrial concentrate of vanadium and nickel. The number of steps N is determined using formulae: bd(nn+nm+1)=a+i=1nmbi+benm, N=nn+nm+1, where nn is the number of steps with recirculation, after which equilibrium output of the low-boiling fractions is achieved; nm is the number of steps with recirculation after achieving equilibrium output of the low-boiling fractions, which enables to achieve a given output of low-boiling fractions from the feed stock; bd is the given output of low-boiling fractions, wt %; a is the output of low-boiling fractions at the zero step, wt %; bi is the output of low-boiling fractions at the i-th step before achieving equilibrium, wt %; be is the output of low-boiling fractions after achieving equilibrium, wt %, be>bd.

EFFECT: high output of low-boiling fractions, low molybdenum consumption, high degree of extraction of molybdenum, vanadium and nickel from the solution, enabling calculation of the required reactor volume, obtaining an industrial concentrate of vanadium and nickel, low hydrogen consumption.

3 cl, 1 dwg, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in obtaining coatings, reducing coefficient of secondary electronic emission, growing diamond films and glasses, elements, absorbing solar radiation. Colloidal solution of nano-sized carbon is obtained by supply of organic liquid - ethanol, into chamber with electrodes, injection of inert gas into inter-electrode space, formation of high-temperature plasma channel in gas bubbles, containing vapours of organic liquid. High-temperature plasma channel has the following parameters: temperature of heavy particles 4000-5000K, temperature of electrons 1.0-1.5 eV, concentration of charged particles (2-3)·1017 cm3, diameter of plasma channel hundreds of microns. After that, fast cooling within several microseconds is performed.

EFFECT: simplicity, possibility to obtain nanoparticles of different types.

3 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to field of nanotechnologies and can be used for obtaining composite materials with high electric and heat conductivity, additives to concretes and ceramics, sorbents, catalysts. Carbon-containing material is evaporated in volume thermal plasma and condensed on target surface 9 and internal surface of collector 7. Plasma generator 3, which includes coaxially located electrodes: rod cathode 4 and nozzle-shaped output anode 5, are used. Gaseous carbon-containing material 6 is supplied with plasma-forming gas through vortex chamber with channels 2 and selected from the group, consisting of methane, propane, and butane. Bottom of collector is made with hole 8 for gas flow to pass.

EFFECT: invention makes it possible to reduce energy consumption of the process, extend types of applied hydrocarbon raw material, simplify device construction and provide continuity of the process and its high productivity.

2 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: method of obtaining a composite material includes the influence on a mixture of a carbon-containing material, filler and sulphur-containing compound by a pressure of 0.1-20 GPa and a temperature of 600-2000°C. As the sulphur-containing compound applied is carbon bisulphide, a compound from the mercaptan group or a product of its interaction with elementary sulphur. As the carbon-containing material applied is molecular fullerene C60 or fullerene-containing soot. As the filler applied are carbon fibres, or diamond, or nitrides, or carbides, or borides, or oxides in the quantity from 1 to 99 wt % of the weight of the carbon-containing material.

EFFECT: obtained composite material can be applied for manufacturing products with the characteristic size of 1-100 cm and is characterised by high strength, low density, solidity not less than 10 GPa and high heat resistance in the air.

11 cl, 3 dwg, 11 ex

FIELD: chemistry.

SUBSTANCE: invention relates to inorganic chemistry, namely to obtaining silicon-carbide materials and products, and can be applied as thermal-protective, chemically and erosion resistant materials, used in creation of aviation and rocket technology, carriers with developed surface of heterogeneous catalysis catalysts, materials of chemical sensorics, filters for filtering flows of incandescent gases and melts, as well as in nuclear power industry technologies. To obtain nanostructures SiC ceramics solution of phenolformaldehyde resin with weight content of carbon from 5 to 40% with tetraethoxysilane with concentration from 1·10-3 to 2 mol/l and acidic catalyst of tetraethoxysilane hydrolysis id prepared in organic solvent; hydrolysis of tetraethoxysilane is carried out at temperature 0÷95°C with hydrolysing solutions, containing water and/or organic solvent, with formation of gel. Obtained gel is dried at temperature 0÷250°C and pressure 1·10-4÷1 atm until mass change stops, after which carbonisation is realised at temperature from 400 to 1000°C for 0.5÷12 hours in inert atmosphere or under reduced pressure with formation of highly-disperse initial mixture SiO2-C, from which ceramics is moulded by spark plasma sintering at temperature from 1300 to 2200°C and pressure 3.5÷6 kN for from 3 to 120 min under conditions of dynamic vacuum or in inert medium. Excessive carbon is burned in air at temperature 350÷800°C.

EFFECT: obtaining nanostructured silicon-carbide porous ceramics without accessory phases.

4 cl, 4 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: first step includes obtaining low-hydroxylated insoluble fullerenols by reacting concentrated fullerene solution in o-xylene with aqueous ammonia solution in the presence of a tetrabutylammonium hydroxide phase-transfer catalyst at 35-40°C. At the second step, the obtained low-hydroxylated insoluble fullerenols are hydroxylated to transform them into a water-soluble form by mixing with 6-15% aqueous hydrogen peroxide solution and heating for 4-5 hours at 65°C. Water-soluble fullerenols are then precipitated from an alcohol-containing solution.

EFFECT: simplifying the method while preserving quality characteristics and full extraction of the end product.

2 cl, 1 dwg, 4 tbl, 3 ex

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