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HL: Halbleiterphysik
HL 38: Poster 2
HL 38.53: Poster
Thursday, March 14, 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.