The invention relates to a method for growing a bulk single crystal, wherein the method comprises the steps of inserting a starting material into a crucible, melting the starting material in the crucible by heating the starting material, arranging a thermal insulation lid at a distance above a melt surface of said melt such that at least a central part of the melt surface is covered by the lid, and growing the bulk single crystal from the melt by controllably cooling the melt with the thermal insulation lid arranged above the melt surface.

A method of additively manufacturing includes generating a thermal model driven scan map that identifies an equiaxed cap region, a single crystal (SX) region, and a columnar to equiaxed transition (CET) region; and forming an active melt pool with respect to the thermal model driven scan map such that a depth of the active melt pool is greater than a thickness of the equiaxed transition (CET) region.

Methods and systems for low etch pit density 6 inch semi-insulating gallium arsenide wafers may include a semi-insulating gallium arsenide single crystal wafer having a diameter of 6 inches or greater without intentional dopants for reducing dislocation density, an etch pit density of less than 1000 cm.sup.2, and a resistivity of 110.sup.7 -cm or more. The wafer may have an optical absorption of less than 5 cm.sup.1 less than 4 cm.sup.1 or less than 3 cm.sup.1 at 940 nm wavelength. The wafer may have a carrier mobility of 3000 cm.sup.2/V-sec or higher. The wafer may have a thickness of 500 m or greater. Electronic devices may be formed on a first surface of the wafer. The wafer may have a carrier concentration of 1.110.sup.7 cm.sup.3 or less.

Methods and systems for low etch pit density gallium arsenide crystals with boron dopant may include a gallium arsenide single crystal wafer having boron as a dopant, an etch pit density of less than 500 cm.sup.2, and optical absorption of 6 cm.sup.1 or less at 940 nm. The wafer may have an etch pit density of less than 200 cm.sup.2. The wafer may have a diameter of 6 inches or greater. The wafer may have a boron concentration between 110.sup.19 cm.sup.3 and 210.sup.19 cm.sup.3. The wafer may have a thickness of 300 m or greater. Optoelectronic devices may be formed on a first surface of the wafer, which may be diced into a plurality of die and optical signals from an optoelectronic device on one side of one of the die may be communicated out a second side of the die opposite to the one side.

Disclosed is a method for melting and solidification of a scintillating material in micromechanical structures, including controlling the melting and solidification of the scintillating material by individually controlled heat sources, a top heater and a bottom heater, placed above and below a process chamber, housing a sample with the micromechanical structures and the scintillating material. The heaters are controlled to set a vertical temperature gradient over the sample to control the melting and solidification of the scintillating material. During melting, the top heater is ramped up and stabilized at a temperature where no melting occurs and the bottom heater is ramped up and stabilized at a temperature where melting occurs during a period of time while the scintillating material melts and flows into the micromechanical structures. During solidification, the temperature of the bottom heater decreases to enable solidification to take place starting from the bottom of the micromechanical structures.

A method of method of forming or repairing a superalloy article having a columnar or equiaxed or directionally solidified or amorphous or single crystal microstructure includes emitting a plurality of laser beams from selected fibers of a diode laser fiber array corresponding to a pattern of a layer of the article onto a powder bed of the superalloy to form a melt pool; and controlling a temperature gradient and a solidification velocity of the melt pool to form the columnar or single crystal microstructure.

A preparation method of high resistance gallium oxide based on deep learning and heat exchange method. The prediction method includes: obtaining a preparation data of the high resistance gallium oxide single crystal, the preparation data including a seed crystal data, an environmental data, a control data, and a raw material data, the control data including a seed crystal coolant flow rate, and the raw material data including a doping type data and a doping concentration; preprocessing the preparation data to obtain a preprocessed preparation data; inputting the preprocessed preparation data into a trained neural network model, and obtaining a predicted property data corresponding to the high resistance gallium oxide single crystal through the trained neural network model, the predicted property data comprises a predicted resistivity. Therefore, the high resistance gallium oxide with a preset resistivity is obtained.

A gas phase nanowire growth apparatus including a reaction chamber, a first input and a second input. The first input is located concentrically within the second input and the first and second input are configured such that a second fluid delivered from the second input provides a sheath between a first fluid delivered from the first input and a wall of the reaction chamber

A method of method of forming or repairing a superalloy article having a columnar or equiaxed or directionally solidified or amorphous or single crystal microstructure includes emitting a plurality of laser beams from selected fibers of a diode laser fiber array corresponding to a pattern of a layer of the article onto a powder bed of the superalloy to form a melt pool; and controlling a temperature gradient and a solidification velocity of the melt pool to form the columnar or single crystal microstructure.

A semiconductor synthesizing device comprises a closed reaction tube, a first furnace body and a second furnace body. The reaction tube is arranged with a plurality of horizontal boat containers which include a plurality of first-layer horizontal boat containers and a second-layer horizontal boat container superposed on a bracket device provided on at least one of the first-layer horizontal boat containers. The bracket device is configured to support the second-layer horizontal boat container and provides a gap between the first-layer horizontal boat container and the second-layer horizontal boat container.