The electronic structure of SiN_x: the valence band DOS and band gaps

Abstract

The valence band densities of states and band gaps of SiNx have been calculated by the Kittler-Falicov method in the one-atom-cluster Bethe lattice approximation. The DOS agrees reasonably well with the photo-emission spectra but the band widths are smaller. The variation of the band gap with x shows the experimentally observed increasing rate of increase with x but the widening of the gap is related to a rapid recession of Ec while the corresponding slow recession of Ev is absent. It is concluded that short-range order plays the dominant role in the electronic structure of SiNx.