Regensburg 2002 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 38: Poster 2

HL 38.53: Poster

Donnerstag, 14. März 2002, 16:30–19:00, Poster A

Phonon-modes and free-carrier-properties of Al- and Ga-doped ZnO and (ZnCdMg)O thin films — •N. Ashkenov¹, C. Bundesmann¹, A. Kasic¹, B. Mbenkum¹, M. Schubert¹, M. Lorenz¹, E. M. Kaidashev², and M. Grundmann¹ — ¹Fakultät für Physik und Geowissenschaften, Institut für Experimentalphysik II, Universität Leipzig, Linnéstraße 5, 04103 Leipzig — ²Rostov State University, Mechanics and Applied Mathematics Research Institute

ZnO and isoelectronically mixed (ZnCdMg)O compounds present an interesting alternative for the wide-band-gap group III-nitrides. Thin films were deposited by pulsed laser deposition on c-plane sapphire. We study the influence of Al and Ga doping in ZnO thin films onto the optical free-carrier properties, and the alloy-induced changes onto the phonon modes in (ZnCdMg)O thin films using infrared spectroscopic ellipsometry and Raman scattering spectroscopy. The phonon modes of the ZnO thin films agree very well with those from bulk reference samples, and we conclude that the ZnO films are fully relaxed. Preliminary data indicate a two-phonon mode behaviour for the E₁(TO) mode, and a one-phonon mode behaviour for the A₁(TO) mode in ZnMgO alloys. Free-carrier effects are extracted from the uniaxial infrared dielectric function, and compared with data from electrical Hall measurements.