SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 51: Nitrides: Preparation and Characterization
HL 51.9: Talk
Friday, March 31, 2023, 11:45–12:00, POT 112
Optical properties of ScN films grown by HVPE and sputter epitaxy — •Jona Grümbel1, Yuichi Oshima2, Christopher Lüttich1, Armin Dadgar1, Martin Feneberg1, and Rüdiger Goldhahn1 — 1Institut für Physik, Otto-von-Guericke-Universität, Universitätsplatz 2, 39106 Magdeburg — 2Environment and Energy Materials Research Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
We investigate the optical properties of rocksalt structured ScN films using spectrocopic ellipsometry and Raman spectroscopy. Two different sets of samples were used for our measurements: (I) ca. 300nm thick ScN grown by sputter epitaxy and (II) 0.4µm up to 40µm thick ScN grown by HVPE. The HVPE grown ScN exhibits a very good crystalline structure, so the carrier concentration varies around 1018cm-3 - 1019cm-3, while for ScN grown by sputter epitaxy the carrier concentrations can reach 1022cm-3 or more. Therefrom we obtain detailed information about their impact on optical properties, such as optical transitions, optical phonon modes or luminescence. Using spectroscopic ellipsometry we arrive at the dielectric function of ScN from 0.04eV to 6.5eV. Detailed analysis yields the main transitions regarding to direct bandgaps at X- and Γ-point as it was already shown in earlier theoretical works. Surprisingly, we observe characteristic peaks in a Raman scattering measurement, although first order Raman scattering is forbidden in rocksalt structured crystals. Detailed discussion and a possible interpretation will be presented as well as ScN materials parameters calculated from our measurements.