Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 26: Poster Session: Heterostructures - Preparation and Characterization - Impurities / Amorphous Semiconductors

HL 26.15: Poster

Monday, March 26, 2012, 16:00–19:00, Poster D

Electronic and optical properties of amorphous semiconductors: a-SiO₂ and a-TiO₂ bulk, solid solution, and interface — •Marc Landmann¹, Thomas Köhler², Eva Rauls¹, Thomas Frauenheim², and Wolf Gero Schmidt¹ — ¹Lehrstuhl für Theoretische Physik, Universität Paderborn, 33095 Paderborn — ²Bremen Center for Computational Materials Science, Universität Bremen, 28359 Bremen

Both titania (TiO₂) and silica (SiO₂) are oxides whose extraordinary physical and chemical properties are demonstrated by manifold traditional fields of application. For gaining a basic estimation of the technological potential of SiO₂/TiO₂ hybrid materials a detailed understanding of the electronic and optical properties of such materials is required. Here, we have calculated the electronic structure and optical response of the SiO₂ and TiO₂ crystalline and amorphous bulk [1,2], solid solution, and interface. The calculations have been done by standard (PBE) and hybrid (HSE06) exchange-correlation functional density-functional theory (DFT). The HSE06 hybrid functional’s suitability to correct for a large part of the DFT intrinsic band gap underestimation and to give a reliable approximation of quasiparticle properties is demonstrated. The optical spectra are calculated in independent particle approximation (IPA) from the DFT band structure and compared to existing experimental data.

[1] M. Landmann et al., submitted to PRB (2011).

[2] M. Landmann et al., to be published.