200results about How to "Reduce lattice defects" patented technology

The invention discloses a GaN-based light-emitting diode epitaxial wafer production method and a produced epitaxial wafer, and belongs to the field of semiconductor light-emitting diodes. The method includes growing a buffer layer, an n-type GaN layer, a stress regulation layer, a multiple quantum well layer, a p-type GaN layer and a p-type ohmic contact layer on a substrate sequentially. The stress regulation layer is of a multi-period structure. A growth method of each period of the multi-period structure includes growing a stress regulation InGaN sub layer at a first growth temperature, supplying hydrogen into a reaction chamber at a second growth temperature after the stress regulation InGaN sub layer finishes growing, and etching the surface of the stress regulation InGaN sub layer, wherein the second growth temperature is different from the first growth temperature. The GaN-based light-emitting diode epitaxial wafer production method and the produced epitaxial wafer have the advantages that through treatment of the stress regulation InGaN sub layer, a smooth contact surface is formed between the stress regulation InGaN sub layer and a stress regulation GaN sub layer, and accordingly, continuous extension of defects is prevented.

An optical system with laser beam uniform irradiation, comprises: a wave-guide space-dividing a laser beam from a light source into divided beams; a superposition lens by which the divided beams are superposition-irradiated on an irradiation face; a delay plate by which beam intensity on the irradiation face is uniform. The wave-guide makes width of the divided beams more than 1/2 times large of a space interference distance on a laser beam section; the delay plate makes a delay of the adjacent divided beams longer than an interference distance of the time of the laser beam, and reduces interference on the irradiation face. An other optical system comprises: a laser beam dividing component for dividing the laser beam into divided beams; a superposition-irradiation component for superposition-irradiating the divided beams on the irradiation face; a homogenization component for homogenizing beam intensity on the irradiation face. The homogenization component includes an optical delay component which makes a delay of the adjacent divided beams longer than an interference distance of the time of the laser beam, a light rotation component which makes polarization directions of the adjacent divided beams actual orthogonal.

The invention discloses a multilayer composite membrane passivation structure of a table top high-power semiconductor device. The multilayer composite membrane passivation structure comprises P-type boron junction areas and an N-type phosphorus junction area, the upper end and the lower end of the N-type phosphorus junction area are provided with the P-type phosphorus areas respectively, and an alpha-polycrystalline silicon layer, a semi-insulating polycrystalline silicon thin membrane, a low-temperature heat oxidation layer, a high-temperature Si3N4 thin membrane, a negative charge glass passivation layer and a low-temperature heat oxidation layer are sequentially arranged on the surface of a PN junction of a table top of the table top high-power semiconductor device from inside to outside. A manufacturing technology of the multilayer composite membrane passivation structure of the table top high-power semiconductor device includes the following steps: a, depositing the alpha-polycrystalline silicon, b, depositing semi-insulating polycrystalline silicon, c, depositing the low-temperature heat oxidation layer, d, depositing Si3N4, e, conducting passivation on glass, and f, depositing the low-temperature heat oxidation layer in the outmost layer. The multilayer composite membrane passivation structure and the manufacturing technology have the advantages that the alpha-polycrystalline silicon layer is deposited, so that crystal lattice adaptation can be achieved, damage to crystal lattices of a silicon wafer in a groove can be repaired, leaked currents in the surfaces of junctions are reduced, and the stability and the reliability of the device at the high temperature are improved.

The invention discloses a preparation method of a high-heat-conductive graphene/chopped carbon fiber composite material. By means of high heat-conductivity of graphene in in-plane direction and high heat-conductivity of carbon fibers in axial direction, the graphene layer and the chopped carbon fibers are subjected to deposition molding in a liquid phase, and by means of adhesion effect of polyimide, the carbon fibers and graphene are connected, and finally, through carbonization and graphitization, the polyimide is converted into graphene, thus manufacturing the whole-carbon high-heat-conductive composite material. A conventional graphene material has ultrahigh heat conductivity in horizontal plane due to the two-dimensional structure of graphene but is poor in heat conductivity since thegraphene is lack in heat conductive path in thickness direction; therefore, by means of the axial high heat-conductivity, the high heat-conductive paths are formed between the graphene layers, so that the heat-conductivity of the material in thickness direction is vertically improved, and the defect of poor heat conductivity in the thickness direction is overcome, thereby preparing the high-heat-conductive material.

The invention provides a cation-anion co-doping n-type zinc-oxide-base transparent conducting film. The doped cation is a high-valency cation M<n+>, and n is 3, 4, 5 or 6; and the doped anion is a low-valency anion X<m->, and m is equal to 1. The preparation method adopts the High-vacuum Magnetron Sputtering technique and promotes the n-type transparent conductivity of the zinc-oxide film by utilizing high-valency cations and low-valency anions to prepare the high-performance cation-anion co-doping zinc-oxide polycrystal film. A compound containing low-valency anions can be used as a fluxing agent to promote the crystallization of the zinc-oxide-base polycrystal film and enhance the visible light transparency of the film and the electron conductivity. The high-performance zinc-oxide-base transparent conducting film has the advantages of simple preparation process, superior visible light transparency and conductivity, and low cost, and has wide application prospects in the fields of solar cells and photoconducting devices.

The invention discloses a film-coating product, in particular relates to film-coating glass capable of being performed with high-temperature thermal treatment. Materials for reflecting infrared film layers of the film-coating product is changed from traditional pure silver materials into alloy materials of silver and niobium, an Agl-aNba film layer deposited by the alloy materials of silver and niobium replaces a pure silver film layer to serve as a functional layer of the film-coating product, stability of films in high-temperature thermal treatment is improved, and simultaneously chemical stability of a silver layer is improved and mechanical performance of the silver layer is improved. The film-coating product has high visible light transmission rate, good mechanical resistance and chemical stability. The film-coating product is mainly used in automobile windshields.

The invention discloses high-performance samarium-cobalt magnetic powder and a preparation method thereof. The general formula is as follows: Sm.alpha.Co. 1-alpha-gamma-delta-psi-omega.Fe.gamma.M.delta.Q.psi.R.omega., and the balance of Co wherein M is at least one of Cu or Zr; Q is at least one of Er, Gd, Dy or Ho; R is at least one of V, Cr, Mn, Sr, Al or Cs; alpha is greater than 20 wt percent and less than 28 wt percent; gamma is greater than 14 wt percent and less than 25 wt percent; delta is greater than 0.5 wt percent and less than 15 wt percent; psi is greater than 0.1 wt percent and less than 5 wt percent; and omega is greater than 0.1 wt percent and is less than 5 wt percent. Due to the composition, the consistency of columnar crystals growth can be promoted, so that the performances of the samarium-cobalt magnetic powder are improved; and the preparation method comprises the following steps of: compounding, smelting, pouring, sintering, solutioning, crushing, aging, adjusting granularity, and the like, so that the magnetic powder with the granularity in bimodal distribution can be prepared, the filler content of the magnetic powder is favored to be improved, and performances of the prepared samarium-cobalt magnetic powder are improved.

The invention provides a single crystal lithium nickel cobalt manganate precursor and a preparation method thereof. The preparation method comprises the following steps: preparing a mixed salt solution, a precipitant solution and a complexing agent solution, and introducing a mixed gas of oxygen and non-oxygen in a volume ratio of 1:19-1:29 into a reaction kettle at a flow rate of 7-20 L/min; adding the mixed salt solution, a sodium hydroxide solution and an ammonia water solution at a flow rate of 60-120 ml/min for reaction; and keeping the pH value at 10.0-11.0, a temperature at 30-60 DEG Cand a stirring rotating speed at 100-500 rpm to obtain the single crystal lithium nickel cobalt manganate precursor, wherein the thickness of the primary particle sheet layer is 100-200 nm, the particle size D50 is 3.0-4.0 [mu]m, and the particle size distribution (D90-D10)/D50 is less than or equal to 0.8. According to the invention, the secondary particle size D50 of the precursor prepared by the method is 3.0-4.0 [mu]m, and the particle size distribution is not more than 0.8; and the single crystal lithium nickel cobalt manganese oxide particles prepared by the precursor are narrow in particle size distribution and good in high and low temperature performance.

The invention discloses a high-thermal-conductivity silicon nitride ceramic substrate and a preparation method thereof, and belongs to the technical field of ceramic substrate materials. The method comprises the following steps: carrying out primary ball milling and mixing on silicon nitride powder, a sintering aid, carbon black, triethyl phosphate and a solvent; adding a binder and a plasticizer,and carrying out secondary ball milling to obtain a slurry; carrying out vacuum defoaming treatment, and then carrying out tape casting to obtain a flaky biscuit; and performing high-temperature sintering after vacuum glue discharging to obtain the silicon nitride ceramic substrate. According to the invention, the carbon black is introduced based on the raw material ratio, and the sintering is carried out by two-step heating, so that the carbon black and the oxygen impurities of the silicon nitride are fully subjected to chemical reaction at a proper temperature and under a proper atmospherecondition, the lattice oxygen content of the silicon nitride ceramic is effectively reduced, and the thermal conductivity of the silicon nitride ceramic is improved. The silicon nitride ceramic substrate prepared by the invention has good performances of high thermal conductivity and high bending strength.

The invention belongs to the field of solar cells, and proposes a method for manufacturing a solar cell. Specifically, the method for manufacturing a solar cell comprises a step of manufacturing textured surface or polished structures on two main surfaces of a substrate; a step of forming a p-type doped doping layer One on a main surface One of the substrate through thermal diffusion; a step of depositing an n-type doped medium membrane on the main surface Two of the substrate or injecting n-type dopant in the main surface Two of the substrate by using an ion injection method; a step of performing annealing processing on the main surface Two of the substrate to form an n-type doped doping layer Two; and a step of depositing medium thin films and hollow-out metal electrodes on the two main surfaces of the substrate. The method is mainly used for manufacturing bifacial solar cells. Compared with methods in the prior art, the method solves technical problems that the manufacture of the bifacial solar cell requires that mutually isolated doping layers be formed on the two main surfaces of the semiconductor substrate in a simpler way, helps to reduce the manufacturing cost and meanwhile helps to improve device performance.

The invention belongs to the technical field of graphene materials and in particular relates to micro-oxidized graphene and a preparation method thereof. The micro-oxidized graphene contains a small amount of active groups, is low in degree of oxidation, and has the oxygen element content of 1-10wt% and the bulk density of 0.01-0.1g/ml. The micro-oxidized graphene contains a proper amount of chemical reaction active group points, and meanwhile, a relatively complete graphene lattice structure is remained so that the micro-oxidized graphene has excellent dispersibility, special reactivity and excellent physical properties. The invention provides an industrial micro-oxidized graphene preparation route which is efficient, stable, economical, controllable and environment-friendly and the defects of uncontrollable graphene activation, great operation risks, serious environmental pollution, serious equipment corrosion, high cost investment and the like of a traditional acid oxidation method can be overcome. The micro-oxidized graphene prepared by use of the preparation method has extremely wide prospect in the fields of functional composites, coatings, ink, photoelectric materials, biological medicine and the like.

The present invention provides a low-pressure diffusion technique in a solar cell silicon wafer production process, and belongs to the technical field of solar cell production. The technical problem that silicon wafer surface diffusion is not uniform in the conventional solar cell silicon wafer production process is solved. The low-pressure diffusion technique comprises a first step of vacuumizing, placing a silicon wafer into a reaction chamber of a diffusion furnace and vaccumizing the reaction chamber of the diffusion furnace to be of a 50 mbar-150 mbar vacuum state by using a vacuum pump; a second step of gas inflation, inflating a small amount of nitrogen and phosphorus oxychloride into the reaction chamber of the diffusion furnace; a third step of low-pressure diffusion, maintaining pressure inside the reaction chamber to be unchanged, low-pressure diffusion time being 700S-900S; and a fourth step of detection, detecting a low-pressure diffusion result to enable silicon wafer surface square resistance to be 80 omega-130 omega per square and uniformity being within +-3%. The technique provided by the present invention has the advantages of excellent diffusion uniformity, sharp reduction in losses of chemicals and special gases, long maintenance cycle, and the like.

The invention provides a double-heterojunction gallium nitride based HEMT (High Electron Mobility Transistor) taking aluminum-gallium-nitrogen as a high-resistance layer, comprising a substrate, a nucleating layer, an unintentionally-doped high-resistance layer, an unintentionally-doped high migration rate layer, an aluminum nitride inserting layer, an unintentionally-doped barrier layer and an unintentionally-doped gallium nitride or aluminum-gallium-nitrogen cap layer, wherein the nucleating layer is manufactured above the substrate and is 0.01-0.50 microns in thickness; the unintentionally-doped high-resistance layer is manufactured above the nucleating layer; the unintentionally-doped high migration rate layer is manufactured above the unintentionally-doped barrier layer; the aluminum nitride inserting layer is manufactured above the unintentionally-doped high migration rate layer and is 0.7-5 nm in thickness; the unintentionally-doped barrier layer is manufactured above the aluminum nitride inserting layer; and the unintentionally-doped gallium nitride or aluminum-gallium-nitrogen cap layer is manufactured above the unintentionally-doped barrier layer and is 1-5 nm in thickness. According to the double-heterojunction gallium nitride, the channel electron migration rate and the limiting capability to two-dimensional electronic gas are obviously improved; power leakage of the buffering layer is inhibited; and meanwhile, crystal lattice stress of the barrier layer is reduced, the defect density is reduced, and the stability and the reliability of the work of a device are improved.

The invention relates to the technical field of semiconductor materials, and discloses a method for preparing a beta-silicon carbide film. The method comprises the following steps: silane is used as a silicon source, hydrogen is used as a diluent gas and a carrier gas for the silicon source, graphite is used as a substrate and a carbon source, the beta-silicon carbide film is prepared on the graphite substrate through a hot filament chemical vapor deposition method, the prepared beta-silicon carbide film is subjected to follow-up annealing treatment in an inert gas, and a finished beta-silicon carbide film is obtained further through micromechanical cleavage. According to the novel method, the beta-silicon carbide film is prepared on the graphite substrate, namely the beta-silicon carbide film is prepared on the graphite substrate which has high electric conductivity and heat conductivity, lattice imperfection inside the film is reduced, the crystalline quality of the film is greatly improved, therefore, the heat dispersion performance of a silicon carbide-based electronic (photoelectronic) high-power device is improved, and the service life of the silicon carbide-based electronic (photoelectronic) high-power device is prolonged; the cleavage of a silicon carbide film material and the graphite substrate is easy to realize through the micromechanical cleavage and other methods, and the method for preparing the beta-silicon carbide film is simple, practicable and low in cost.

The invention discloses a superlattice graded buffer layer transmission-type AlGaN ultraviolet photoelectric cathode and a preparation method therefor. The photoelectric cathode consists of a substrate layer, a superlattice wedge graded p-type AlxGa1-xN buffer layer, a p-type AlyGa1-yN emission layer and a Cs or Cs/O activation layer from bottom to top, wherein the superlattice wedge graded p-type AlxGa1-xN buffer layer consists of 8-15 cyclically stacked graded layers and one transitional layer; the transitional layer is in contact with the emission layer; and the lowest graded layer is in contact with the substrate layer. According to the ultraviolet cathode and the preparation method, the growth quality of crystals is improved, the lattice defects in the buffer layer are reduced to a relatively large extent, the photon absorption rate of the emission layer is increased, and finally the photoelectric emission quantum efficiency of the photoelectric cathode is improved.

The invention discloses a ZnO/SiC/Si heterojunction solar battery and a preparation method thereof, wherein the solar battery comprises a substrate layer, a SiC layer arranged on the substrate layer and a ZnO layer arranged on the SiC layer, wherein the material of the substrate layer in the ZnO/SiC/Si heterojunction solar battery is Si piece. The thickness of the substrate layer is 3-4mm, the thickness of the SiC layer is 500-3000nm, and the thickness of the ZnO layer is 300-2000nm. The preparation method comprises utilizing a chemical vapor deposition method to firstly prepare the SiC layer on the substrate, and then preparing the ZnO layer, and the method for preparing ZnO is a chemical vapor deposition method or a reactive sputtering method. The solar battery improves the crystallization quality of heterogeneous epitaxial films, obviously improves photoelectric transformation efficiency, can improve more than 1 time than a solar battery which is directly made of ZnO/Si, and has extremely wide application prospect.

The invention relates to a carbon raw material for a carbon composite refractory material and a preparation method thereof. The technical scheme comprises the following steps: firstly uniformly filling the bottom of a graphite crucible with a monatomic silicon powder, uniformly coating the monatomic silicon powder with graphite, carrying out thermal insulation at 1000-1400 DEG C in the atmosphere of argon or nitrogen for 1-4 hours, and taking out a substance which covers the monatomic silicon powder so as to prepare the carbon raw material for the carbon composite refractory material, wherein graphite is one of expandable graphite and graphene, and mass ratio of graphite to the monatomic silicon powder is (0.01-0.9):1. By adjusting the mass ratio of graphite to the monatomic silicon powder, in-situ preparation of different numbers and sizes of silicon carbide whiskers is realized on the edge of graphite. The prepared carbon raw material for the carbon composite refractory material has excellent resistance to oxidation, good dispersibility and excellent mechanical properties, is used in a carbon composite refractory material, and can be used to raise overall performance of a carbon composite refractory material and especially enhance mechanical properties and oxidation resistance of the carbon composite refractory material.

The invention discloses ordered large-area single-layer microspheres/nanospheres assisted by a template and a preparation method thereof, and belongs to the technical field of preparation of a semiconductor material. According to the method, a structure with a certain size is produced on a substrate, and an obtained product is used as the template; and single-layer microspheres are deposited on the template, and after liquid is evaporated, an ordered large-area single-layer microsphere/nanosphere structure assisted by the template is obtained. The ordered large-area single-layer microspheres/nanospheres obtained by the invention have few defects, are high in orientation orderness, and nearly have no multi-layer phenomenon; and when the microspheres/nanospheres are visually observed from a scanning electron microscope photograph, excellent orderness of the ordered large-area single-layer microspheres/nanospheres can be seen.