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HL: Fachverband Halbleiterphysik
HL 35: Poster I
HL 35.34: Poster
Dienstag, 8. März 2016, 15:00–19:00, Poster A
Carrier-induced refractive index change observed by a whispering gallery mode shift in GaN microrods — •Christian Tessarek1,2,3, Rüdiger Goldhahn4, George Sarau1,2, Martin Heilmann2, and Silke Christiansen1,2,5 — 1Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin — 2Max Planck Institute for the Science of Light, Erlangen — 3Institute of Optics, Information and Photonics, Friedrich-Alexander-University Erlangen-Nürnberg — 4Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg — 5Physics Department, Freie Universität Berlin
The influence of the carrier concentration on the refractive index of GaN is investigated. Vertical oriented GaN microrods were grown by metal-organic vapor phase epitaxy. During growth the silane flux was modified to obtain four sections with different n-type carrier concentrations above 1019 cm−3 along the c-axis. Whispering gallery modes can be observed in this type of microrods due to the regular hexagonal shape, the smooth sidewall facets and the sharp edges [1]. The presence of an energy dependent mode shift with respect to the four microrod sections with different doping concentrations is attributed to a carrier-induced refractive index change. The observed mode shift can be calculated by a proper adjustment of the band gap parameter in the analytical expression of the refractive index [2].
[1] C. Tessarek et al., ACS Photonics 1, 990 (2014).
[2] C. Tessarek et al., New J. Phys. 17, 083047 (2015).