Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 17: Organic Semiconductors
HL 17.3: Talk
Tuesday, March 19, 2024, 10:00–10:15, EW 015
Isotope effects in Ga- and O-rich monoclinic β-Ga2O3 — •Daniel Cierpinsky1, Benjamin M. Janzen1, Andrea Ardenghi2, Oliver Bierwagen2, Piero Mazzolini3, Roland Gillen4, Janina Maultzsch4, Andreas Falkenstein5, Joe Kler5, Roger Souza5, Manfred Martin5, and Markus R. Wagner2,1 — 1Technische Universität Berlin, Germany — 2Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany — 3University of Parma, Italy — 4Chair of Experimental Physics, Erlangen, Germany — 5RWTH Aachen University, Aachen, Germany
We employ polarization-dependent confocal micro-Raman spectroscopy to study the vibrational properties of isotopic β-Ga2O3. For this purpose samples were fabricated using molecular beam homoepitaxy to produce thin films of 18O isotopic Ga2O3 on non isotopic 16O Ga2O3 substrate, with growth conditions ranging from metal- to oxygen-rich regimes. We determine the spectral position of all Raman active phonon modes with high precision and observe that the substitution of 16O with 18O leads to shifts towards lower frequencies for all modes due to the higher isotopic mass. The isotopically induced shifts and their variations resulting from different growth regimes are discussed in conjunction with DFT calculations on the phonon energy contribution of lattice sites as well as SIMS measurements.
Keywords: Gallium Oxide; Raman