Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 57: Focussed Session: ZnO-based Semiconductors
HL 57.3: Vortrag
Donnerstag, 25. März 2010, 14:45–15:00, H17
Uniaxial stress dependent analysis of the optical and vibrational properties of high quality ZnO substrates — •Gordon Callsen1, Markus R. Wagner1, Ronny Kirste1, Jan Schulze1, Axel Hoffmann1, Anna V. Rodina2, and André Schleife3 — 1Technische Universität Berlin, Department of solid state physics, Hardenbergstr. 36, 10623 Berlin, Germany — 2A. F. Ioffe Physico-Technical Institute, 194021 Sankt-Petersburg, Russia — 3Friedrich-Schiller-Universität, Institut für Festkörpertheorie, Max-Wien-Platz 1, 07743 Jena, Germany
We analyze ZnO substrates from suppliers like Cermet, Crystek, Tokyo Denpa and UniWafer by PL and Raman measurements with strong focus on the observed uniaxial stress dependencies. Zero stress field PL measurements reveal varying energetic positions of the e.g. bound excitons and exciton-polaritons among the selection of ZnO substrates which indicates different built-in strain levels. Polarization dependent PL measurements under application of uniaxial stress yield different pressure coefficients for the full set of exciton-polaritons of all analyzed ZnO substrates. Therefore, different dependencies for the evolution of the A-C- and A-B-exciton-polariton-splitting under the influence of uniaxial stress are measured. First principal calculations which model the influence of uniaxial strain on the electronic band structure of ZnO allow detailed insight into the obtained PL results. Uniaxial stress dependent Raman measurements facilitate further comparison of the analyzed ZnO substrates based on their vibrational properties which are also directly influenced by the application of uniaxial stress.