Provided are a structure for producing a high-quality single crystal diamond, and a method for manufacturing the structure for producing diamond. A structure for producing a diamond is composed of a base substrate and an Ir thin film formed on the base substrate. The thermal expansion coefficient of the base substrate is 5 times or less of the thermal expansion coefficient of diamond and the melting point of the base substrate is 700° C. or higher. The peak angle in the X-ray diffraction pattern of the Ir thin film is different from the peak angle in the X-ray diffraction pattern of the base substrate.

A method for producing a Group III nitride crystal including preparing an RAMgO.sub.4 substrate containing a single crystal represented by the general formula RAMgO.sub.4 (wherein R represents one or a plurality of trivalent elements selected from the group consisting of Sc, In, Y, and a lanthanoid element, and A represents one or a plurality of trivalent elements selected from the group consisting of Fe(III), Ga, and Al); and growing a Group III nitride crystal containing Mg on the RAMgO.sub.4 substrate.

A SiC crystal manufacturing method is based on a sublimation recrystallization method. The SiC crystal manufacturing method includes preparing a crucible including a support portion on an inner surface of the crucible; introducing raw material into the crucible; providing a stress-buffering sheet on the support portion, a bottom surface of the stress-buffering sheet having a region where a SiC crystal grows; installing a lid on the crucible, the lid having a projection on a surface thereof facing the stress-buffering sheet, the projection projecting towards the region of the stress-buffering sheet where the SiC crystal grows; and growing the SiC crystal on the bottom surface of the stress-buffering sheet by sublimating the raw material introduced into the crucible.

An object of the present invention is to provide a novel technique capable of manufacturing a large-diameter AlN substrate.

The present invention is a method for manufacturing an AlN substrate, including a crystal growth step S30 of forming an AlN layer 20 on a SiC underlying substrate 10 having through holes 11. In addition, the present invention is a method for forming an AlN layer including the through hole formation step S20 of forming the through holes 11 in the SiC underlying substrate 10 before forming the AlN layer 20 on the SiC underlying substrate 10.

A group III nitride single crystal substrate including a main surface, the main surface including: a center; a periphery; an outer region whose distance from the center is greater than 30% of a first distance, the first distance being a distance from the center to the periphery; and an inner region whose distance from the center is no more than 30% of the first distance, wherein a ratio (ν.sub.A−ν.sub.B)/ν.sub.B is within the range of ±0.1%, wherein ν.sub.A is a minimum value of peak wave numbers of micro-Raman spectra in the inner region; and ν.sub.B is an average value of peak wave numbers of micro-Raman spectra in the outer region.

A silicon carbide seed crystal and method of manufacturing the same, and method of manufacturing silicon carbide ingot are provided. The silicon carbide seed crystal has a silicon surface and a carbon surface opposite to the silicon surface. A difference D between a basal plane dislocation density BPD1 of the silicon surface BPD1 and a basal plane dislocation density BPD2 of the carbon surface satisfies the following formula (1):

D=(BPD1−BPD2)/BPD1≤25%  (1).

A silicon carbide wafer and a method of fabricating the same are provided. In the silicon carbide wafer, a ratio (V:N) of a vanadium concentration to a nitrogen concentration is in a range of 2:1 to 10:1, and a portion of the silicon carbide wafer having a resistivity greater than 10.sup.12 Ω.Math.cm accounts for more than 85% of an entire wafer area of the silicon carbide wafer.

A method for manufacturing a SiC single crystal reducing crystallinity degradation at a wafer central portion wherein a growth container surrounds a heat-insulating material with a top temperature measurement hole, a seed crystal substrate at an upper portion inside the container, and a silicon carbide raw material at a lower portion of the container and sublimated to grow a SiC single crystal on the seed crystal substrate. A center position hole deviates from a center position of the seed crystal substrate and moves to the periphery side of the center of the seed crystal substrate. A SiC single crystal substrate surface is tilted by a {0001} plane and used as the seed crystal substrate. The SiC single crystal grows with the seed crystal substrate directed to a normal vector of the seed crystal substrate basal plane parallel to the main surface and identical to the hole in a cross-sectional view.

The present invention relates to the technical field of superlattice magneto-optical material technologies, and in particular, to a superlattice material, and a preparation method and application thereof. According to description of embodiments, the superlattice material provided in the present invention has both a relatively good magnetic property of a ferrous garnet material and a good photoelectric absorption characteristic of a two-dimensional semiconductor material such as graphene. Magneto-optical Kerr effect data obtained through testing shows that: A saturated magneto-optical Kerr angle of the superlattice material in the present invention is 13 mdeg in a magnetic field of 2500 Oe, and a magneto-optical Kerr angle of the superlattice material is increased by 2.5 times compared with a nonsuperlattice ferrimagnetic thin film material into which no two-dimensional material is inserted, thereby achieving magneto-optical effect enhancement.

A hybrid growth method for III-nitride tunnel junction devices uses metal-organic chemical vapor deposition (MOCVD) to grow one or more light-emitting or light-absorbing structures and ammonia-assisted or plasma-assisted molecular beam epitaxy (MBE) to grow one or more tunnel junctions. Unlike p-type gallium nitride (p-GaN) grown by MOCVD, p-GaN grown by MBE is conductive as grown, which allows for its use in a tunnel junction. Moreover, the doping limits of MBE materials are higher than MOCVD materials. The tunnel junctions can be used to incorporate multiple active regions into a single device. In addition, n-type GaN (n-GaN) can be used as a current spreading layer on both sides of the device, eliminating the need for a transparent conductive oxide (TCO) layer or a silver (Au) mirror.