Single crystal of highly purified hexagonal boron nitride capable of far ultraviolet high-luminance light emission, process for producing the same, far ultraviolet high-luminance light emitting device including the single crystal, and utilizing the device, solid laser and solid light emitting unit

A method for producing highly pure hexagonal boron nitride single crystals with far ultraviolet light emission characteristics, wherein the highly pure hexagonal boron nitride single crystals with far ultraviolet light emission characteristics emitting far ultraviolet light having the maximum light emission peak in the far ultraviolet region at a wavelength of 235 nm or shorter are produced through the procedures of mixing boron nitride crystals with a highly pure solvent, melting the same by heating under high-temperature and high-pressure, and recrystallizing the same.

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

A solid-state far ultraviolet laser characterized by the generation of laser light with a far ultraviolet region wavelength, using a highly pure hexagonal boron nitride crystal with far ultraviolet light emission characteristics as a direct-type semiconductor solid-state light emitting element and combining therewith an electron beam irradiation apparatus as an exciting source.

A solid-state far ultraviolet light emitting apparatus, wherein a light emitting layer consisting of a highly pure hexagonal boron nitride single crystal capable of emitting far ultraviolet light with a single emission peak in far ultraviolet region at a wavelength of 235 nm or shorter and an exciting means for exciting said light emitting layer are combined and encapsulated together into a vacuum container, and the light emitting layer is excited to emit far ultraviolet light by operation of the exciting means.