Exciton optical transitions in a hexagonal boron nitride single crystal

Abstract

Abstract Near band gap photoluminescence (PL) of a hexagonal boron nitride single crystal has been studied at cryogenic temperatures with synchrotron radiation excitation. The PL signal is dominated by trapped‐exciton optical transitions, while the photoluminescence excitation (PLE) spectra show features assigned to free excitons. Complementary photoconductivity and PLE measurements set the band gap transition energy to 6.4 eV and the Frenkel exciton binding energy larger than 380 meV. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)