Ultraviolet luminescence spectra of boron nitride single crystals grown under high pressure and high temperature

作者：Watanabe K^*; Taniguchi T; Kanda H

来源：Physica Status Solidi A-Applications and Materials Science, 2004, 201(11): 2561-2565.

DOI：10.1002/pssa.2004005188

Boron nitride (BN) single crystals grown by employing a temperature gradient method under high-pressure and high-temperature conditions using a carefully purified Ba-B-N solvent system showed exciton-related cathodoluminescence peaks in the ultraviolet region around 200 nm. A series of peaks from the cubic phase of BN single crystal was assigned as the phonon-assisted free-exciton luminescence bands from which the indirect exciton gap energy was estimated to be 6.17 eV. The exciton binding energy was estimated to be 80 meV based on the temperature dependence of the exciton luminescence intensity. A dominant luminescence peak from hexagonal-phase BN single crystal was observed at 215 run, which is 1000 times larger than the indirect exciton luminescence of type IIa diamond. This intense luminescence suggests that hexagonal BN is a direct band gap material.

• 出版日期2004-9