Deep UV Photoluminescence and Chemical composition Analysis of Residual Impurities in Hexagonal boron nitride

Single crystal hexagonal boron nitride (h-BN) is an ultrawide (~6.0 eV) semiconductor under development for electronic, optoelectronic and nanophotonic devices. A key issue in these applications is the effect of impurities, especially oxygen, on its properties. Here the properties and compositions of h-BN and oxidized h-BN were compared. The deep UV photoluminescence spectra from h-BN samples were oxidized at 900 ^oC in dry and ambient air, had strong phonon-assisted band edge emissions along with a sharp atomic-like emission line at 4.09 eV, and its phonon replicas at 3.89 and 3.69 eV. The sharp emission line and phonon replicas were not observed in unoxidized sample. Comparative chemical composition analysis of the residual impurities was carried out using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (TOF-SIMS) in order to identify the impurities related to the sharp transition. Our results of atomic like features could have potential applications in the solid-state single photon source for quantum information technologies.