In an embodiment a growth substrate includes a substrate and a buffer layer sequence having a plurality of semiconductor layers based on a nitride semiconductor compound material and a plurality of buffer layers, wherein the semiconductor layers and the buffer layers are arranged alternatingly, and wherein the buffer layers comprise at least one of the following two-dimensional layered materials: graphene, boron nitride, MoS.sub.2, WSe.sub.2 or fluorographene.

Some aspects for the invention include a method and a structure including a light-emitting device disposed over a second crystalline semiconductor material formed over a semiconductor substrate comprising a first crystalline material.

Some embodiments include a method. The method can include: providing a carrier substrate; forming a first device material over the carrier substrate; and after forming the first device material over the carrier substrate, transforming the first device material into a second device material. Meanwhile, the transforming the first device material into the second device material can include: causing a cationic exchange in the first device material; and causing an anionic exchange in the first device material. The causing the cationic exchange in the first device material and the causing the anionic exchange in the first device material can occur approximately simultaneously. Other embodiments of related methods and systems are also disclosed.

An alumina sintered body of the present invention has a degree of c-plane orientation of 5% or more, which is determined by a Lotgering method using an X-ray diffraction profile in a range of 2=20 to 70 obtained under X-ray irradiation, and an XRC half width of 15.0 or less in rocking curve measurement, an F content of less than 0.99 mass ppm when measured by D-SIMS, a crystal grain diameter of 15 to 200 m, and 25 or less pores having a diameter of 0.2 m to 1.0 m when a photograph of a viewing area 370.0 m in a vertical direction and 372.0 m in a horizontal direction taken at a magnification factor of 1000 is visually observed.

An InGaN-based LED epitaxial wafer and a fabrication method thereof are disclosed, wherein the InGaN-based LED epitaxial wafer includes: a substrate; an InGaN layer, formed on a surface of the substrate, having an In content between 40% and 90%, so as to ensure that the LED epitaxial wafer is capable of emitting long-wavelength light or near-infrared rays; a p-type metal oxide layer, formed on a surface of the InGaN layer facing away from the substrate, acting as a hole injection layer for the InGaN layer.

Light-emitting materials are made from a porous light-emitting semiconductor having quantum dots (QDs) disposed within the pores. According to some embodiments, the QDs have diameters that are essentially equal in size to the width of the pores. The QDs are formed in the pores by exposing the porous semiconductor to gaseous QD precursor compounds, which react within the pores to yield QDs. According to certain embodiments, the pore size limits the size of the QDs produced by the gas-phase reactions. The QDs absorb light emitted by the light-emitting semiconductor material and reemit light at a longer wavelength than the absorbed light, thereby down-converting light from the semiconductor material.

In an embodiment a growth substrate includes a substrate and a buffer layer sequence having a plurality of semiconductor layers based on a nitride semiconductor compound material and a plurality of buffer layers, wherein the semiconductor layers and the buffer layers are arranged alternatingly, and wherein the buffer layers comprise at least one of the following two-dimensional layered materials: graphene, boron nitride, MoS.sub.2, WSe.sub.2 or fluorographene.

An alumina sintered body of the present invention has a degree of c-plane orientation of 5% or more, which is determined by a Lotgering method using an X-ray diffraction profile in a range of 2=20 to 70 obtained under X-ray irradiation, and an XRC half width of 15.0 or less in rocking curve measurement, an F content of less than 0.99 mass ppm when measured by D-SIMS, a crystal grain diameter of 15 to 200 m, and 25 or less pores having a diameter of 0.2 m to 1.0 m when a photograph of a viewing area 370.0 m in a vertical direction and 372.0 m in a horizontal direction taken at a magnification factor of 1000 is visually observed.

Some embodiments include a method. The method can include: providing a carrier substrate; forming a first device material over the carrier substrate; and after forming the first device material over the carrier substrate, transforming the first device material into a second device material. Meanwhile, the transforming the first device material into the second device material can include: causing a cationic exchange in the first device material; and causing an anionic exchange in the first device material. The causing the cationic exchange in the first device material and the causing the anionic exchange in the first device material can occur approximately simultaneously. Other embodiments of related methods and systems are also disclosed.