Regensburg 2022 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 18: Oxide Semiconductors (joint session HL/KFM)

HL 18.5: Talk

Wednesday, September 7, 2022, 10:30–10:45, H33

Phonons, Isotope Effects, and Point Defects in β-Ga2O3 — •Benjamin M. Janzen¹, Piero Mazzolini^2,3, Roland Gillen⁴, Andreas Falkenstein⁵, Vivien F. S. Peltason¹, Hans Tornatzky¹, Daniel Cierpinsky¹, Andrea Ardenghi², Manfred Martin⁵, Janina Maultzsch⁴, Roberto Fornari^2,3, Zbigniew Galazka⁶, Oliver Bierwagen², and Markus R. Wagner¹ — ¹Technische Universität Berlin, Institute of Solid State Physics, Berlin, Germany — ²Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V, Germany — ³Department of Mathematical, Physical and Computer Sciences, University of Parma, Italy — ⁴Chair of Experimental Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany — ⁵Institute of Physical Chemistry, RWTH Aachen University, Germany — ⁶Leibniz-Institut für Kristallzüchtung, Berlin, Germany

We present a combined experimental and theoretical study of lattice vibrations in a homoepitaxial β-Ga2O3 thin film grown by MBE with different oxygen isotopes (16O, 18O). Using polarized first- and second order micro-Raman spectroscopy, we identified all 15 first-order Raman modes of β-Ga2O3. In combination with density functional perturbation theory calculations, we identify the atomistic origins (Ga-Ga, Ga-O or O-O) of all Raman active phonon modes in β-Ga2O3 by quantifying the isotopically-induced relative frequency shifts of the individual Raman modes and investigate the presence of point defects on specific lattice sites.