High pressure synthesis of UV-light emitting cubic boron nitride single crystals

摘要

Single crystals of cubic boron nitride were synthesized under high pressure and high temperature by using temperature gradient method. When Be was added to the solvent for the crystal growth in such systems as Li-B-N and Ca-B-N, grown crystals were dark blue in color and exhibited p-type conduction as characterized by Hall measurement. It was found that Be atoms localized in the particular growth sectors in the single crystals, when the Be concentration was small in the growth condition. Across the boundaries of these growth sectors, Be-rich blue region was clearly divided from amber colored region with less Be content. When a d.c. voltage was applied across the boundaries, ultraviolet light emission was observed from them, suggesting spontaneous formation of p-n domain in the grown crystals.