Electronic structures, effective masses and optical properties of B₆Ch (Ch=O, S, Se, Te) based on DFT study

In this paper, crystal structures, effective masses, electronic and optical properties of B₆Ch (Ch = O, S, Se, Te) are studied within density functional theory (DFT). The band structures show that B₆O, B₆S and B₆Se are semiconductors, while the zero-bandgap B₆Te displays metallic properties. Moreover, the optical properties involving absorption coefficients, refractive index and extinction coefficients of B₆Ch are shown and analyzed. The obtained results lead to a conclusion that B₆Ch results in heavier effective masses and poor transparency. This is explained by the fact that the s orbitals of anion will cause lower dispersion of band edge and influence its positions.