Identification of ternary boron–carbon–nitrogen hexagonal phases by x-ray absorption spectroscopy

Boron carbon nitride (BCN) films have been grown by ${\mathrm{B}}_{\mathrm{4}}\mathrm{C}$ evaporation with concurrent ${\mathrm{N}}_2^{+}$ ion assistance, and have been characterized by x-ray absorption near edge (XANES) spectroscopy. Upon the nitrogen insertion, the film structure evolves from ${\mathrm{B}}_x\mathrm{C}$ -like to $\mathrm{h-}\mathrm{BN}$ -like. The hexagonal structure corresponds to a true ternary BCN compound that can be understood as $\mathrm{h-}\mathrm{BN}$ with carbon incorporated in substitutional sites. The $\mathrm{C(1}\mathrm{s)}\mathrm{XANES}$ presents π^* states characteristic of the BCN arrangement. The basal planes of the $\mathrm{h-}\mathrm{BCN}$ phase are oriented perpendicular to the substrate, as derived from the angle dependence of the XANES signal.