Regensburg 2002 – scientific programme

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HL: Halbleiterphysik

HL 38: Poster 2

HL 38.23: Poster

Thursday, March 14, 2002, 16:30–19:00, Poster A

Fröhlich mode in GaN columnar nanostructures — •G. Irmer¹, J. Monecke¹, I.M. Tiginyanu², A. Sarua², S.M. Hubbard³, D. Pavlidis³, and V. Valiaev³ — ¹Institut für Theoretische Physik, Technische Universität Bergakademie Freiberg — ²Laboratory of Low-Dimensional Semiconductor Structures, Institute of Applied Physics, Technical University of Moldova, 2004 Chisinau, Moldova — ³Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor, MI 48109-2122, USA

GaN columnar nanostructures fabricated by electrochemical dissolution of bulk material have been studied by micro-Raman spectroscopy. The anodization induces an increase in the intensity of Raman scattering accompanied by a breakdown of the polarization selection rules and by the appearance of a new mode at 716 cm^{− 1}, i.e. in the frequency gap between the transverse optical and longitudinal-optical bulk phonons. We present a Raman line-shape analysis based on the effective dielectric function of a composite that brings to light the Fröhlich character of this mode.