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HL: Fachverband Halbleiterphysik

HL 44: Poster Session I

HL 44.24: Poster

Dienstag, 15. März 2011, 18:00–21:00, P3

Electronic and Optical Properties of Group-III Nitride Alloys from ab-initio Methods — •Luiz Cláudio de Carvalho, André Schleife, Abderrezak Belabbes, Cláudia Rödl, and Friedhelm Bechstedt — Institut für Festköpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany

Group-III mononitrides and their alloys are subject of intense investigations due their interesting electronic and optical properties. First-principles calculations based on the density functional theory, hybrid functionals, and an iterative solution of the quasiparticle equation with the exchange-correlation self-energy in GW approximation have demonstrated to give electronic structures in good agreement with spectroscopic data. Recently, a new approach called LDA-1/2, was proposed based on the concept of half occupation. Applied to excitation energies in solids one overcomes the band-gap problem and obtains reliable electronic properties with less computer-time demands. In the present work, electronic and optical properties of wurtzite group-III nitrides alloys are studied within the cluster expansion approximation. Three different cluster statistics, GQCA, SRS and MDM, are applied in order to illustrate different preparation techniques. The calculations are performed using implement atoms in the VASP code. Based on the LDA-1/2 method electronic structures, are derived optical absorption spectra including electron-hole interaction and local-field effects are computed as a function of composition by solving the Bethe-Salpeter equation. The computed spectra are analyzed and compared to available experimental data.