Effects of unique band structure of h-BN probed by photocurrent excitation spectroscopy

Abstract

Abstract By employing a photocurrent excitation spectroscopy measurement, a direct bandgap of ∼6.46 eV has been resolved for the first time in thick B-10 enriched h-BN films. Together with previous band calculations, an unconventional energy diagram has been constructed to capture the unique features of h-BN: h-BN has a minimum direct bandgap of ∼6.5 eV and a bandgap of ∼6.1 eV which is indirect with the conduction band minimum (CBM) at M-point and valence band maximum (VBM) at K-point in the Brillouin zone, and the energy levels of the donor and acceptor impurities are measured relative to CBM and VBM, respectively.