Structural and electronic properties of MgGe x Sn(1-x)N2 semiconductors: The density functional theory investigation

In this work, we studied the lattice dynamics and electronic structures of nitride semiconductors MgGe x Sn(1-x)N2, where x = 0, 0.25, 0.5, 0.75 and 1, using density functional theory (DFT) calculations. The core electronic states were represented via ultrasoft pseudo-potentials. From the results, lattice constants of MgGe x Sn(1-x)N2 compounds decrease with increasing Ge concentrations according to the Vegard’s law, where the lattice bowing coefficients p a , p b and p c are 0.043, –0.019 and 0.087 Å respectively. For the electronic band structure, the N-p dominated valence band was found to shift down and IV-s dominated conduction band moves up with increasing the Ge concentrations. In addition, the energy gap bowing coefficients p e is 0.916 eV.