Carrier-induced refractive index change observed by a whispering gallery mode shift in GaN microrods

Language
en
Document Type
Article
Issue Date
2015-10-30
Issue Year
2015
Authors
Tessarek, Christian
Goldhahn, R.
Sarau, G.
Heilmann, M.
Christiansen, S.
Editor
Abstract

Vertical oriented GaN microrods were grown by metal-organic vapor phase epitaxy with four different n-type carrier concentration sections above 1019 cm−3 along the c-axis. In cathodoluminescence investigations carried out on each section of the microrod, whispering gallery modes can be observed due to the hexagonal symmetry. Comparisons of the spectral positions of the modes from each section show the presence of an energy dependent mode shift, which suggest a carrier-induced refractive index change. The shift of the high energy edge of the near band edge emission points out that the band gap parameter in the analytical expression of the refractive index has to be modified. A proper adjustment of the band gap parameter explains the observed whispering gallery mode shift.

Journal Title
New Journal of Physics
Volume
17
Issue
8
Citation
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