Aluminum oxide provides, at a thickness of 5 mm, an internal transmittance of 90% or higher for light at a wavelength of 193 nm.

Aluminum oxide provides, at a thickness of 5 mm, an internal transmittance of 90% or higher for light at a wavelength of 193 nm.

A method for treating a jewel of the monocrystalline or polycrystalline type (20), in particular for the watchmaking industry, the jewel (20) including a body (23) defining the shape thereof. The method includes a step of ion implantation on the surface (24) of at least a part of the body (23) to modify the roughness of the surface (24).

A method for treating a jewel of the monocrystalline or polycrystalline type (20), in particular for the watchmaking industry, the jewel (20) including a body (23) defining the shape thereof. The method includes a step of ion implantation on the surface (24) of at least a part of the body (23) to modify the roughness of the surface (24).

There is provided an aluminum nitride laminate member including: a sapphire substrate having a base surface on which bumps are distributed periodically, each bump having a height of smaller than or equal to 500 nm; and an aluminum nitride layer provided on the base surface and having a surface on which protrusions are formed above the apices of the bumps.

There is provided an aluminum nitride laminate member including: a sapphire substrate having a base surface on which bumps are distributed periodically, each bump having a height of smaller than or equal to 500 nm; and an aluminum nitride layer provided on the base surface and having a surface on which protrusions are formed above the apices of the bumps.

There is provided an aluminum nitride laminate member including: a sapphire substrate having a base surface on which bumps are distributed periodically, each bump having a height of smaller than or equal to 500 nm; and an aluminum nitride layer grown on the base surface and having a flat surface, there being substantially no voids in the aluminum nitride layer.

There is provided an aluminum nitride laminate member including: a sapphire substrate having a base surface on which bumps are distributed periodically, each bump having a height of smaller than or equal to 500 nm; and an aluminum nitride layer grown on the base surface and having a flat surface, there being substantially no voids in the aluminum nitride layer.

An optoelectronic device includes a flexible substrate, a cerium oxide (CeO.sub.2) layer arranged on the flexible substrate, a single crystal β-III-oxide layer arranged on the CeO.sub.2 layer, and a metallic contact layer arranged on the single crystal β-III-oxide layer.

An alumina grain has a single-crystal structure and has an approximate regular octahedral stereoscopic morphology. Eight sides of the alumina grain belong to the {111} family of crystal planes of γ-state alumina, and the grain size is 5-100 μm. The alumina grain is unique in crystal plane exposure and distribution, simple and feasible in preparation, and low in cost, and has higher operability, and thus has good application prospect in the field of catalysis and adsorption.