First principles studies of band structure and electronic properties of ZnSe

The structural and electronic properties of semiconductor ZnSe are investigated by performing first principles calculations using density functional theory (DFT). The exchange correlation potentials were treated within the local density approximation (LDA) and the generalized gradient approximation (GGA) with the quantum espresso package. We calculate the density of state (DOS), projected density of state (PDOS), phonon dispersion frequencies and the electron charge density. Also, the bulk modulus and its pressure derivatives are determined. Where available, the calculated quantities are compared with known results. The electronic band structure revealed an occurrence of a 2.72 eV band gap, while the density of state shows split peak at -2eV and a minor peak split between 8 and 11 eV. We show that from the gamma points, along the high symmetries Gamma -> X and Gamma -> L directions, there are four dispersion (OL, OT, AL and AT) mode curves which later split into six modes along the Gamma -> X (2OL, OT, 2AT, and AL), L -> X (2OT, OL, 2AT, and AL), X -> W (2OL, OT, 2AT, and AL) and W -> L (2OT, OL, 2AT, and AL) directions. These modes splitting correspond to optical longitudinal mode, optical transverse mode, acoustic longitudinal mode and acoustic transverse mode. (C) 2011 Elsevier B. V. All rights reserved.