Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 91: Poster Session: Quantum dots and wires: preparation & characterization & optical properties & transport properties

HL 91.5: Poster

Thursday, March 14, 2013, 16:00–20:00, Poster A

Structural and electronic and optical properties of Si_xGe_1−x alloy nanocrystals embedded in SiO₂: First-principles calculations — •Kaori Seino¹, Peter Kroll², Moritz Laubscher¹, and Friedhelm Bechstedt¹ — ¹nstitut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Jena, Germany — ²Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA

Silicon-Germanium (SiGe) technology is the driving force behind the explosion in low-cost, personal communication devices. Combining two major semiconductors, these alloys allow tailoring of the band gap and fundamental properties that depends on it in both bulk systems and nanocrystals (NCs). Recent advances in Group-IV semiconductor NCs have demonstrated their promise for optoelectronic and photovoltaic applications. Current developments of photonic devices focus on size control and ordered arrangements of NCs embedded in a SiO₂.

Our understanding of SiGe alloy NCs embedded in SiO₂ is, however, limited. Therefore, in this study we provide theoretical investigations of such systems. We study structural and electronic properties of Si_xGe_1−x alloy NCs with well-defined sizes embedded in silica glass by means of first-principles calculations. We investigate their electronic and optical properties and how their depends on the compositional parameter x of Si_xGe_1−x alloys.