Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 25: Poster Session: GaN - Optical Properties & Preparation and Characterization & Devices

HL 25.8: Poster

Monday, March 26, 2012, 16:00–19:00, Poster D

Investigation of Parametrizations for the Valence Band Structure of GaN — •Felix Schwarz, Steve Lenk, and Erich Runge — Institut für Physik und Institut für Mikro- und Nanotechnologien, Technische Universität Ilmenau, 98693 Ilmenau, Germany

We calculate the dielectric function of hexagonal GaN including the A-, B-, and C-excitons using a multi-valence band formalism. The importance of excitons for the interpretation of reflectance spectroscopy of GaN was emphasized by several experimental groups, but only recently theoretical calculations were presented [1]. We obtain the dielectric function from a numerical solution of an initial-value problem [2] via an exponential split-operator method, taking into account the full 6x6 valence band structures of several parametrizations calculated by other groups. We present the complex dielectric function as well as the deduced reflectivity spectra of the excitons in GaN. After comparing the results to recent experimental spectra, we present an semi-empirically adapted parametrization for the valence band structure.

[1]

A. T. Winzer, G. Gobsch, and R. Goldhahn, Phys. Rev. B 74, 125207 (2006).

[2]

S. Glutsch, Excitons in Low−Dimensional Semiconductors, Springer Heidelberg (2004).