2 00 3 Electronic structure of wurtzite and zinc - blende AlN

The electronic structure of AlN in wurtzite and zinc-blende phases is studied experimentally and theoretically. By using x-ray emission spectroscopy , the Al 3p , Al 3s and N 2p spectral densities are obtained. The corresponding local and partial theoretical densities of states (DOS) , as well as the total DOS and the band structure , are calculated by using the full potential linearized augmented plane wave method , within the framework of the density functional theory. There is a relatively good agreement between the experimental spectra and the theoretical DOS , showing a large hybridization of the valence states all along the valence band. The discrepancies between the experimental and theoretical DOS , appearing towards the high binding energies , are ascribed to an underestimation of the valence band width in the calculations. Differences 1 between the wurtzite and zinc-blende phases are small and reflect the slight variations between the atomic arrangements of both phases .