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HL: Fachverband Halbleiterphysik

HL 39: Optical properties

HL 39.2: Vortrag

Dienstag, 12. März 2013, 10:30–10:45, H13

Raman scattering study of phonon-polaritons in wurtzite GaN — •Christian Röder, Gert Irmer, Cameliu Himcinschi, and Jens Kortus — TU Bergakademie Freiberg, Institute of Theoretical Physics, Leipziger Str. 23, D-09596 Freiberg, Germany

Reports on Raman measurements of polaritons in uniaxial semiconductors are scarce. However, the Raman scattering efficiency of polaritons can be described taking both into account, an atomic displacement term and an electro-optic contribution which depends very strongly on the polariton frequency. The relation between the atomic displacement tensor components and the electro-optic ones is expressed using the Faust-Henry coefficients. According to the symmetry of wurtzite GaN three different Faust-Henry coefficients are implied. In order to specify charge carrier concentration and mobility in GaN by Raman spectroscopy the values of these parameters are required but they are still debated. In this work we present Raman scattering results on phonon-polaritons in single crystals of wurtzite GaN. The experiments were conducted in near-forward scattering geometry. Measurements of ordinary and extraordinary polaritons with defined symmetry could be performed. The observed dispersion curves and scattering efficiency results are compared with theoretical ones. The authors would like to thank the European Union (EFRE) as well as the Free State of Saxony for financial support within the ADDE project.