The electronic structure of GaN and a single Ga-vacancy in GaN crystal

The spin-polarized, all-electron, full-potential ab initio calculations have been performed for the electronic structure of a wide band-gap semiconductor GaN using the self-consistent cluster-embedding (SCCE) calculation method. The obtained band-gap and relative positions of N 2p, N 2s and Ga 3d valence bands agree with the experimental data. Using the bulk results, the electronic structure of a single Ga-vacancy in GaN crystal (without lattice distortion) is calculated. It is shown that the Fermi level around the Ga-vacancy is much higher than the Fermi level of a normal lattice. So it should be easy for the 2p electrons at the Fermi level, which belongs to the N atoms around the Ga-vacancy, to become conducting electrons at the normal lattice.