Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 81: Focus Session: Extended defects in semi- and nonpolar GaN II

HL 81.4: Talk

Thursday, March 14, 2013, 15:30–15:45, H13

Anisotropy of the optical response of nonpolar GaN in spectroscopic ellipsometry — •Karsten Lange, Christian Lidig, Martin Feneberg, Matthias Wieneke, Hartmut Witte, Armin Dadgar, Jürgen Bläsing, Alois Krost, and Rüdiger Goldhahn — Institut für Exp. Physik Otto-von-Guericke-Universität Magdeburg

A-plane Ge or Si doped GaN layers with electron concentrations between 7× 10¹⁸ cm⁻³ and 2× 10²⁰ cm⁻³ were grown by metal-organic chemical vapour desposition. On these layers spectroscopic ellipsometry is carried out in order to determine both the ordinary and extraordinary dielectric tensor components. The infrared studies yield optical phonon frequencies influenced by plasmon-phonon coupling, opening a possibility to systematically determine the anisotropy of GaN. Thus, an experimental measure of the electron effective mass anisotropy is obtained. Furthermore, we will discuss first results of the related anisotropic shifts of the absorption edge around the fundamental band gap.