Theoretical investigations of a new two-dimensional semiconducting boron-carbon-nitrogen structure.

A new two-dimensional boron-carbon-nitrogen (BCN) structure is predicted and is theoretically investigated based on density functional theory. The BCN structure belongs to the space group 222, and is composed of twelve B, twelve C and twelve N atoms per orthorhombic cell (named oC-BCN). It consists of small hollow spheres with two hexagons per sphere. The dynamical, thermal and mechanical stabilities of oC-BCN are respectively evaluated by phonon spectroscopy, molecular dynamics calculations and elastic constant measurements. The simulated in-plane stiffness and Poisson ratio display anisotropic features. The band structure shows that oC-BCN is a direct semiconductor with a gap of 2.72 eV (GW). oC-BCN has an absorption range from the visible light spectrum to the ultraviolet. Therefore, due to its small direct band gap and optical absorption, oC-BCN may be a good candidate for electronic and optical applications.