To fabricate a practically useful non-polar AlN buffer layer on a sapphire crystal plate and manufacture a UV light-emitting device on a non-polar crystal substrate by adopting the crystal substrate as an example, an embodiment of the present invention provides a crystal substrate 1D comprising an r-plane sapphire crystal plate 10 and an AlN buffer layer 20D of non-polar orientation. The AlN buffer layer comprises a surface protection layer 22 and a smoothing layer 26. The surface protection layer suppresses roughness increase on a surface of the AlN buffer layer, and the smoothing layer makes the surface of the AlN buffer layer a smoothed surface. Also provided is a crystal substrate 11 comprising an AlN buffer layer 20T to which a dislocation blocking layer 24 for reducing crystallographic defects is added between the surface protection layer 22 and the smoothing layer 26. In another embodiment a deep UV light-emitting device is provided.

A step-flow growth of a group-III nitride single crystal on a silicon single crystal substrate is promoted. A layer of oxide oriented to a <111> axis of silicon single crystal is formed on a surface of a silicon single crystal substrate, and group-III nitride single crystal is crystallized on a surface of the layer of oxide. Thereupon, a <0001> axis of the group-III nitride single crystal undergoing crystal growth is oriented to a c-axis of the oxide. When the silicon single crystal substrate is provided with a miscut angle, step-flow growth of the group-III nitride single crystal occurs. By deoxidizing a silicon oxide layer formed at an interface of the silicon single crystal and the oxide, orientation of the oxide is improved.

An alumina substrate having a carbon-containing phase with an AlN layer formed on a surface of the alumina substrate.

A method is disclosed for making semiconductor films from a eutectic alloy comprising a metal and a semiconductor. Through heterogeneous nucleation said film is deposited at a deposition temperature on relatively inexpensive buffered substrates, such as glass. Specifically said film is vapor deposited at a fixed temperature in said deposition temperature where said deposition temperature is above a eutectic temperature of said eutectic alloy and below a temperature at which the substrate softens. Such films could have widespread application in photovoltaic and display technologies.

The subject of the invention is the use, as catalyst support sublayer in a process for growing carbon nanotubes by chemical vapour deposition (CVD), of a multilayer stack formed of alternating layers of silica and of alumina, each of the layers having a thickness of less than or equal to 10 nm and consisting of one or more superposed atomic monolayer(s). It also relates to a multilayer structure comprising a substrate which has, on at least one of its faces, such a multilayer stack, and also to the use thereof for the growth of a mat of carbon nanotubes, which are in particular spinnable, by chemical vapour deposition, preferably hot-filament chemical vapour deposition.

A Group III nitride substrate contains a base material part of a Group III nitride having a front surface and a back surface, the front surface of the base material part and the back surface of the base material part having different Mg concentrations from each other.

Lattice-mismatched epitaxial films formed proximate non-crystalline sidewalls. Embodiments of the invention include formation of facets that direct dislocations in the films to the sidewalls.

A Group III nitride substrate contains a base material part of a Group III nitride having a front surface and a back surface, the front surface of the base material part and the back surface of the base material part having different Mg concentrations from each other.

An epitaxial wafer including: a silicon-based substrate; a first buffer layer on the substrate and including a first multilayer structure buffer region composed of Al.sub.xGa.sub.1-xN layers and Al.sub.yGa.sub.1-yN layers (x>y) alternately disposed and a first insertion layer composed of an Al.sub.zGa.sub.1-zN layer (x>z) and is thicker than the Al.sub.yGa.sub.1-yN layer, the first regions and insertion layers alternately disposed; a second buffer layer on the first and including a second multilayer structure buffer region composed of Al.sub.αGa.sub.1-αN layers and Al.sub.βGa.sub.1-βN layers (α>β) alternately disposed and a second insertion layer composed of an Al.sub.γGa.sub.1-γN layer (α>γ) and is thicker than the Al.sub.βGa.sub.1-βN layer, the second regions and insertion layers alternately disposed; and a channel layer on the second buffer layer and thicker than the second insertion layer. The average Al composition in the second buffer layer is higher than that in the first.

Systems and methods for gallium nitride growth on silicon. A semiconductor device, comprising a silicon (001) substrate. A graphene layer on the silicon (001) substrate, wherein the graphene layer is synthesized without a metallic catalyst, and a gallium nitride-based layer over the graphene layer. Methods for growing a gallium nitride layer on silicon are also taught.