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HL: Fachverband Halbleiterphysik

HL 97: ZnO

HL 97.5: Talk

Friday, March 15, 2013, 10:30–10:45, H16

The role of the surface in resonance Raman scattering in ZnO and other wurtzites — •Christian Kranert, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Semiconductor Physics Group, Leipzig, Germany

We apply the double resonance model of R. M. Martin [1] to the resonance Raman scattering by longitudinal optical (LO) phonons in ZnO, excited well above the band gap (λ=325 nm). By extending this model with an elastic scattering process at the surface, we provide an improved understanding of the physical background and the spectral properties of the 1LO line. The consideration of the surface-related process, additionally to the well-established elastic scattering by point defects, is essential to conclusively explain several experimental findings. Particularly, the dependence of the peak position on the orientation of the excited surface cannot be understood otherwise. It was previously attributed to the varying wave vectors of the incident and scattered light in the literature which we will disprove theoretically and experimentally. We will present similar experimental results for other wurtzites (GaN, InN, CdS) which show the general validity of this extended model.

[1] R. M. Martin, Phys. Rev. B 10, 2620 (1974)