Aluminum oxide (Al.sub.2O.sub.3) thin films having a high γ-phase purity and low defect density and methods for making the aluminum oxide thin films are provided. Also provided are epitaxial heterostructures that incorporate the aluminum oxide thin films as growth substrates and methods of forming the heterostructures. The Al.sub.2O.sub.3 films are pure, or nearly pure, γ-Al.sub.2O.sub.3. As such, the films contain no, or only a very low concentration of, other Al.sub.2O.sub.3 polymorph phases. In particular, the Al.sub.2O.sub.3 films contain no, or only a very low concentration of, the θ-Al.sub.2O.sub.3 polymorph phase.

A method and system are provided for crystallizing thin films with a laser system. The method includes obtaining a thin film comprising a substrate and a target layer that contains nano-scale particles and is deposited on the substrate. The heat conduction between the target layer and the substrate of the thin film is determined based on thermal input from the laser system to identify operating parameters for the laser system that cause crystallization of the nano-scale particles of the target layer in an environment at near room temperature with the substrate remaining at a temperature below the temperature of the target layer. The laser system is then operated with the determined operating parameters to generate a laser beam that is transmitted along an optical path to impinge the target layer. The laser beam is pulsed to create a localized rapid heating and cooling of the target layer.

A method and system are provided for crystallizing thin films with a laser system. The method includes obtaining a thin film comprising a substrate and a target layer that contains nano-scale particles and is deposited on the substrate. The heat conduction between the target layer and the substrate of the thin film is determined based on thermal input from the laser system to identify operating parameters for the laser system that cause crystallization of the nano-scale particles of the target layer in an environment at near room temperature with the substrate remaining at a temperature below the temperature of the target layer. The laser system is then operated with the determined operating parameters to generate a laser beam that is transmitted along an optical path to impinge the target layer. The laser beam is pulsed to create a localized rapid heating and cooling of the target layer.

A method of fabricating a wafer according to the embodiment comprises the steps of growing an wafer on a surface of the wafer in a growth temperature; and cooling the wafer after the wafer has been grown, wherein a stepwise cooling is performed when cooling the wafer.

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

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

The present invention discloses a copper-zinc-aluminum-iron single crystal alloy material having an ultra-large grain structure of 5-50 cm grade, obtained by annealing an as-cast alloy having a polycrystalline structure through a single phase region of 800-960° C. for 2-105 h, where the as-cast alloy includes, by weight percentage, 62-82% of copper, 6-29% of zinc, 5-12% of aluminum, and 2-5% of iron. In the present invention, the alloy compositions have an essential difference and are a copper-zinc-aluminum-iron quaternary alloy, and the iron element is an indispensable alloying element. The preparation process of the present invention is extremely simple and very easy to implement and has a very good application prospect.

The present invention discloses a copper-zinc-aluminum-iron single crystal alloy material having an ultra-large grain structure of 5-50 cm grade, obtained by annealing an as-cast alloy having a polycrystalline structure through a single phase region of 800-960° C. for 2-105 h, where the as-cast alloy includes, by weight percentage, 62-82% of copper, 6-29% of zinc, 5-12% of aluminum, and 2-5% of iron. In the present invention, the alloy compositions have an essential difference and are a copper-zinc-aluminum-iron quaternary alloy, and the iron element is an indispensable alloying element. The preparation process of the present invention is extremely simple and very easy to implement and has a very good application prospect.

In one embodiment, a method for surface passivation for CdTe devices is provided. The method includes adjusting a stoichiometry of a surface of a CdTe material layer such that the surface becomes at least one of stoichiometric or Cd-rich; and reconstructing a crystalline lattice at the surface of the CdTe material layer by annealing the adjusted surface.

A process for forming graphene, includes: depositing at least a first and a second metal onto a surface of silicon carbide (SiC), and heating the SiC and the first and second metals under conditions that cause the first metal to react with silicon of the silicon carbide to form carbon and at least one stable silicide. The corresponding solubilities of the carbon in the stable silicide and in the second metal are sufficiently low that the carbon produced by the silicide reaction forms a graphene layer on the SiC.