Composition-dependent photoluminescence and electronic structure of 2-dimensional borocarbonitrides, BC _XN (x = 1, 5)

Layered borocarbonitrides BCN and BC₅N with a wide difference in composition have been prepared by the urea route. These 2D materials show a significant difference in the photoluminescence spectra, with BCN and BC₅N showing maxima at 340 and 410 nm (3.61 and 3.0 eV), besides exhibiting different electrical resistivities. First-principles calculations show that BCN and BC₅N are associated with different band gaps, the gap of the carbon-rich composition being lower. The change in the electronic structure and properties is related to the composition of BC _XN i.e. the ordering of the graphene and BN domains. (papers)