Theoretical study on the electronic and optical properties of B-doped zinc-blende GeC

A first-principles study based on the density functional theory has been carried out to investigate the electronic and optical properties of zinc-blende GeC1−xBx with various boron concentrations. The calculated lattice parameters of zinc-blende GeC are in good agreement with the previous computations, and the substitution of C with B in GeC induces an increase in the lattice parameters. The calculated results show that the band gap of GeC transforms from indirect band gap to direct band gap and shrinks after C atom is replaced by B atom. The static dielectric constants of B-doped GeC are found to be remarkably large, so it may act as a new dielectric material. Furthermore, after B doping, a new absorption peak appears in the infrared band (0–2 eV) and will intensify with the increase of doping concentration. All the calculated optical properties show a red shift property.