SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: Poster II

HL 33.42: Poster

Wednesday, March 29, 2023, 17:00–19:00, P1

Temperature dependent Raman spectroscopy on GaN:Si — •Christina Harms, Jona Grümbel, Martin Feneberg, and Rüdiger Goldhahn — Institut für Physik, Otto-von-Guericke-Universität Magdeburg, Germany

GaN structures are of high interest for optical and electronic applications in current research projects. We investigate the Raman excitations of hexagonal bulk GaN:Si under temperature variation from 80 K up to 300 K. Seven samples with carrier concentrations ranging between 10¹² - 10¹⁹ cm^-3 were measured using laser excitation of 532 nm. It is shown, that within room temperature measurements both coupled phonon-plasmon-modes (LPP_±) are visible and follow the prediction of polaritonic excitations. Under variation of temperature the LPP₊ mode shows a weak frequency shift with elevated temperature or remains unaffected for low carrier concentrations. Surprisingly, the LPP₋ mode shifts towards lower frequencies with increasing temperatures for all samples, which contradicts previous assumptions. A qualitative description of the results and possible interpretations will be presented. Additionally, we also investigated the temperature dependent FWHM of the LPP_± mode and the E₂ phonon mode. Here, both behaviours match the theoretical and experimental previous research.