44results about How to "Improve single crystal quality" patented technology

The invention relates to a large single crystal graphene and preparation method thereof. The preparation method comprises the following steps: 1) annealing a copper base under reducing atmosphere to obtain annealed copper base; 2) under triazine derivative steam atmosphere, treating the copper base annealed after the annealing treatment in the step 1) to obtain the copper base after the triazine derivative treatment, wherein the triazine derivative is selected from at least one of tripolycyanamide, 2,4-diamino-6-methyl-1,3,5-triazine, and 2-amino-4-methyl-6-methoxy-1,3,5-triazine; 3) depositing graphene on the surface of the copper base subjected to triazine derivative biological treatment by adopting a chemical vapor deposition method to obtain the large single crystal graphene. The preparation method is simple and suitable for large-scale production, the single crystal domain size achieves sub-centimeter level, and the single crystal quality is high and can be applied to the electronics.

The invention provides a growth method of a germanium-doped SiC body single-crystal material. The method adopts a sublimation method to make germanium-doped single crystals grow in a high-temperature single-crystal growth furnace and comprises the specific growth steps that the positions of high and low temperature zones are determined according to the shape of a residual material left at the bottom of the inside of a crucible after crystal growth; a dopant is put at the corresponding positions of the high and low temperature zones respectively to make the crystals grow; cooling is performed to reach room temperature, and high-quality germanium-doped SiC single crystals are obtained. The method enables the germanium element to be put in the high and low temperature zones respectively according to the temperature field distribution characteristics of induction heating, achieves uniform doping in the whole crystal growth process, controls the vapor pressure of the germanium at a preliminary growth stage, prevents germanium atom agglomeration on the growth face and achieves uniform doping in the radial and axial directions. The crystal defects and internal stress are reduced. Obtained single-crystal defects are few, the single-crystal quality is high, and the stress is small.

The invention discloses large-area molecular crystal and a preparation method thereof. The preparation method for the large-area molecular crystal comprises the following steps that an organic semiconductor solution is placed on a substrate with a hydrophobic property, a substrate with a hydrophily property covers the substrate with the hydrophobic property, and after growth, molecular crystal canbe obtained on the substrate with the hydrophily property; the organic semiconductor solution adopts at least one of chlorobenzene solvent, trichloromethane solvent, dichlorobenzene solvent and xylene solvent; the mass volume density of the organic semiconductor solution is 0.01 mg/mL-15 mg/mL; the solutes of the organic semiconductor solution are organic semiconductor molecules. The large-area molecular crystal has the advantages of a large area, high uniformity and a flat surface, a field effect transistor prepared by the large-area two-dimensional molecular crystal has higher carrier mobility rate and lower threshold voltage, and solid foundation is laid for the preparation of later P-N heterojunction.

The invention belongs to the technical field of single crystal thin films, and particularly relates to a surface treatment method for stripping a single crystal thin film through ion implantation. According to the surface treatment method for stripping the single crystal thin film through ion implantation, argon ion etching is selected for accurately removing a damaged layer on the surface of thesingle crystal thin film prepared through the ion implantation stripping technology; and besides, the problems of oxygen vacancy defects and surface modification of the film after the damaged layer isremoved are solved by respectively controlling the oxygen flux, the working power and the working parameters of the cleaning time in the oxygen plasma cleaning process, the cleaning effect is verified through the contact angle test, and finally, the single crystal thin film is completely infiltrated, so that the subsequent preparation of a graphical device structure is facilitated. According to the method, the single crystal quality of the single crystal thin film is greatly improved, the introduced secondary damage is minimum, and the process complexity is simplified.

A novel re-feeding device for Czochralski grown monocrystalline is provided, including a re-feeding cylinder, a quartz umbrella disposed at the lower end of the re-feeding cylinder and a fixed frame at the upper end of the re-feeding cylinder. The re-feeding cylinder sequentially includes, from one end close to the fixed frame, a first cylinder part, a second cylinder part and a third cylinder part. The first, second and third cylinder parts are integrally connected, the inner diameter of the first cylinder part is greater than the inner diameter of the third cylinder part, and the height of the first cylinder part is not less than the height of the third cylinder part. The re-feeding device can increase the re-feeding amount of each cylinder, can reduce the oxygen content of head gaps ofmonocrystalline silicon rods, and can improve monocrystalline silicon quality. The service lifetime of the re-feeding device is prolonged, the production efficiency is increased and the production cost is reduced. The invention also provides an operating method of the novel re-feeding device for Czochralski grown monocrystalline. The method is particularly suitable for re-feeding for monocrystalline silicon with a large size and a large feeding amount. Through the method, quality of monocrystalline silicon rods can be ensured, and the crystal yield is increased by about 4%.

The invention discloses a fixed device and a fixing method for a seed crystal or a substrate in the single crystal growth of aluminum nitride. A detachable growth platform is arranged between an aluminum nitride powder source and a crucible head cover, so that the seed crystal or substrate material is fixed by means of gravity or in a mechanical mode, crystal growth can be carried out on double surfaces of the seed crystal or substrate simultaneously by setting a first gap and a second gap, the crystal growth efficiency is relatively high, the problem of seed crystal fixation is effectively solved, various adverse factors caused by adhesion of the seed crystal are avoided, and advantages are provided for homoepitaxial growth of aluminum nitride; the seed crystal or substrate gets close toa high temperature area from a low temperature area, a gas phase substance generated through degradation of the aluminum nitride powder source has preferable transfer ability in the high temperature area, and is beneficial for further homoepitaxial/heteroepitaxial growth to further enlarge crystal size; the formation of a white ceramic layer can be avoided completely on the surface of the seed crystal, the single crystal induction effect of the seed crystal is developed, and the aluminum nitride single crystal obtained through the method has extremely high single crystal quality and has relatively high crystal growth rate.

The invention provides a preparation method of a high-quality wafer-level graphene single crystal. The method comprises the following steps: placing plasma-treated metal foil into a reaction furnace,introducing an inert atmosphere, performing heating to an annealing temperature, introducing hydrogen gas, and performing annealing treatment, wherein the metal foil is one selected from the group consisting of copper foil, nickel foil, molybdenum foil and cobalt foil, the plasma treatment atmosphere is at least one selected from the group consisting of air, hydrogen gas, argon gas, oxygen gas, and nitrogen gas, the power is 100-150 W, the pressure is 400-500 Pa, and the time is 1-30 min; and introducing a carbon source into the reaction furnace, adjusting the annealing temperature to a growthtemperature of the graphene single crystal, starting growth of the graphene single crystal, and after growth is completed, performing cooling to a room temperature.

The invention discloses a perovskite nanowire array and a preparation method thereof, and the preparation method comprises the following steps: S1, preparing a silicon column template with a plurality of silicon column arrays, and carrying out the selective modification of the silicon column template; S2, preparing a perovskite solution; S3, dropwise adding a perovskite solution to the top end of the silicon column of the silicon column template; S4, covering the top of the silicon column template with a substrate to form a sandwich assembly system; S5, carrying out heating and drying treatment on the sandwich assembly system; S6, standing and cooling the heated and dried sandwich assembly system; and S7, dismounting the sandwich assembly system. According to the preparation method, the equipment cost is effectively reduced, and the perovskite nanowire array of which the frequency doubling conversion efficiency is far higher than that of the perovskite polycrystalline thin film is prepared and obtained simply and universally at the same time.

The invention provides a semiconductor/metal/semiconductor quantum well structure, which is characterized in that the semiconductor/metal/semiconductor quantum well structure comprises a first semiconductor layer, a metal Al film layer and a second semiconductor layer, the metal Al film layer is sandwiched between the first semiconductor layer and the second semiconductor layer, and the metal Al film layer is a single crystal with unique orientation and has no twin crystal. The invention also provides a preparation method of the semiconductor/metal/semiconductor quantum well structure. The metal Al thin film epitaxially prepared by the two-step method is flat in surface, high in single crystal quality, free of twin crystal and low in optical loss, and the semiconductor/metal/semiconductor quantum well structure can be used for a semiconductor quantum information device.