Crystallization of hexagonal boron nitride exhibiting excitonic luminescence in the deep ultraviolet region at room temperature via thermal chemical vapor phase deposition

Boron nitride exhibiting intense exciton-related luminescence at 216–227 nm in the ultraviolet (UV) region was synthesized on nickel substrates by chemical vapor phase deposition using the BCl3-NH3 system. We investigated the effects of the deposition temperature and flow rate ratio of source gases on the cathodoluminescence property in the deep ultraviolet (DUV) light region measured at room temperature. UV-luminous hBN can form at temperatures of 1170 °C and above with a ratio of NH3 gas flow to BCl3 flow of 2 or below. Drastic surface roughening accompanies the formation of UV-luminous hBN with high crystallinity, showing that the etching process of nickel substrates by BCl3 at high temperatures is related to the formation of UV-luminous hBN.