There is provided a production apparatus of a gallium oxide crystal using a resistance heater, the heater provided therein being capable of being provided at a low cost and capable of suppressing deformation and breakage due to heat. The production apparatus for a gallium oxide crystal according to one or more aspects of the present invention includes a furnace body constituted by a heat resistant material, a crucible disposed in the furnace body, and a heater disposed around the crucible, the heater being a resistance heater including a heating part and a conductive part having a larger diameter than the heating part connected to each other, the heating part being constituted by a material having heat resistance to 1,850° C., the conductive part being constituted by a material having heat resistance to 1,800° C.

The gallium arsenide single crystal substrate has a circular main surface, and when the diameter of the main surface of the gallium arsenide single crystal substrate is represented by D and the number of etch pits formed on the main surface by immersing the gallium arsenide single crystal substrate in molten potassium hydroxide at 500° C. for 10 minutes is counted, the number C.sub.1 of etch pits in a first circular region having a diameter of 0.2D around the center of the main surface is 0 or more and 10 or less.

A luminescent material can include an element or an interstitial site that provides a hole trap in the luminescent material; a first dopant that provides a first electron trap in the luminescent material; and a second dopant that provides a second electron trap in the luminescent material, wherein the second dopant is a relatively shallower electron trap as compared to the first dopant. In an embodiment, a ratio of the first dopant to the second dopant is in a range of 10:1 to 100:1 on an atomic basis. In another embodiment, a ratio of the first dopant to the second dopant is selected so that luminescent material has a lower average value for a departure from perfect linearity in a range of 5 keV to 20 keV that is less to other luminescent materials of the same base compound. The luminescent material may not be a rare earth halide.

A method for producing a single crystal having a diameter of 200 mm or greater in which: (1) a seed crystal is provided; (2) an upper surface of the seed crystal is melted with an infrared ray supplied obliquely from above to create a melt covering the upper surface of the seed crystal; and (3) a powder raw material is supplied from above the seed crystal onto an area of the melt that is 90% or less of a diameter of the seed crystal, and the powder raw material supplied onto the melt is melted with the infrared ray supplied obliquely from above to melt the powder raw material while, simultaneously, a lower surface of the melt is solidified on the seed crystal. The infrared ray is applied to an area of the melt that is within 90% of the diameter of the seed crystal.

Produced is a large single crystal with no crystal grain boundary, which is a high-quality single crystal that has a uniform composition in both the vertical and horizontal directions at an optimum dopant concentration. Provided is a single-crystal production equipment including, at least: a granular raw material supply apparatus which supplies a certain amount of a granular raw material downward; a granular raw material melting apparatus which heats and melts the granular raw material and supplies the thus obtained raw material melt downward; and a crystallization apparatus which allows a single crystal to precipitate out of a mixed melt that is formed upon receiving a melt formed by irradiating an infrared ray from a first infrared ray irradiation equipment to the upper surface of a seed single crystal and the raw material melt supplied from the granular raw material melting apparatus.

An apparatus for casting a part that includes a first housing, a second housing, a handling system and a cooling apparatus. The first housing defines a first chamber. The first chamber is configured to receive a melt heater and a mold heater. The second housing is configured to move between a first position and a second position such that when the second housing is in the first position, the first housing is open such that a mold can be inserted therein and when the second housing is in the second position, the second housing and the first housing define a second chamber. The cooling apparatus is configured to be positioned within the second chamber.

A method for casting a part, that includes the steps of: introducing a mold into a first housing; engaging the first housing with a second housing to define a second chamber; melting an ingot within the furnace; reducing pressure within the second chamber to a first predetermined pressure; pouring at least a portion of the melted ingot into the mold; adding an gas to the second chamber to raise the pressure to a second predetermined pressure; moving the mold such that it is engaged with the means for cooling; and solidifying the liquid metal within the mold.

Methods for forming single crystal silicon ingots in which plural sample rods are grown from the melt are disclosed. A parameter related to the impurity concentration of the melt or ingot is measured. In some embodiments, the sample rods each have a diameter less than the diameter of the product ingot.

A gallium oxide crystal manufacturing device includes a crucible to hold a gallium oxide source material therein, a crucible support that supports the crucible from below, a crucible support shaft that is connected to the crucible support from below and vertically movably supports the crucible and the crucible support, a tubular furnace core tube that surrounds the crucible, the crucible support and the crucible support shaft, a tubular furnace inner tube that surrounds the furnace core tube, and a resistive heating element including a heat-generating portion placed in a space between the furnace core tube and the furnace inner tube. Melting points of the furnace core tube and the furnace inner tube are not less than 1900° C. A thermal conductivity of a portion of the furnace core tube located directly next to the crucible in a radial direction thereof is higher than a thermal conductivity of the furnace inner tube.

A method is provided. The method includes providing an alignment structure at least partially defining a predetermined alignment pattern. The method also includes forming a solid crystal on the alignment structure. Crystal molecules of the solid crystal are aligned in the predetermined alignment pattern.