National Institute for Materials Science

National Institute for Research in Inorganic Materials

Satoshi Koizumi

Masayuki Katagiri

Takashi Taniguchi

Takatoshi Yamada

Kenji Watanabe

Hisao Kanda

Nesladek Milos

Yasuo Koide

Mutsukazu Kamo

Tokuyuki Teraji

Hiroyuki Ozaki

A method for producing hexagonal boron nitride single crystals including mixing boron nitride crystals with a solvent thereby obtaining a mixture, heating and melting the mixture under high-temperature and high-pressure thereby obtaining a melted mixture, and recrystallizing the melted mixture thereby producing hexagonal boron nitride single crystals, wherein the solvent is boronitride of alkaline earth metal, or boronitride of alkali metal and the boronitride of alkaline earth metal.

Method for producing hexagonal boron nitride single crystals

The diamond semiconductor device is a diamond semiconductor device where a pair of electrodes are fixed on a diamond substrate, and wherein at least one interface to the electrode on the surface of the diamond substrate has a hydrogen termination and at least the surface of the substrate between the pair of two electrodes is controlled to have a larger electric resistivity value than inside the substrate. Accordingly, a diamond semiconductor device can be realized, capable of attaining the device work stability, especially the device work stability in severe environments such as high temperature with exhibiting the function of the hydrogen termination thereof to the utmost extent.

Diamond semiconductor device

A solid-state far ultraviolet light emitting element is formed by a hexagonal boron nitride single crystal, excited by electron beam irradiation to emit far ultraviolet light having a maximum light emission peak in a far ultraviolet region at a wavelength of 235 nm or shorter.

Solid-state high-luminance far ultraviolet light emitting element including highly pure hexagonal boron nitride single crystal

A synthesis of phosphorus-doped diamond by a microwave plasma method using a volatile hydrocarbon and hydrogen mixed therewith, as a reaction gas, wherein phosphorus is used as a dopant, and hydrogen bonded to the phosphorus is dissociated so that the phosphorus is introduced into diamond as an impurity without being bonded to hydrogen.

Synthesis of phosphorus-doped diamond

Growing community of inventors

Tsukuba, Japan

Satoshi Koizumi