Berlin 2024 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HL: Fachverband Halbleiterphysik
HL 25: Oxide Semiconductors I
HL 25.5: Talk
Wednesday, March 20, 2024, 10:30–10:45, ER 325
Raman active phonon modes of single-domain orthorhombic κ-Ga2O3 — •Alwin Wüthrich1, Benjamin M. Janzen1, Hiroyuki Nishinaka2, Roland Gillen3, and Markus R. Wagner1,4 — 1Technische Universität Berlin — 2Kyoto Institute of Technology — 3Friedrich-Alexander Universität Erlangen-Nürnberg — 4Paul-Drude-Institut für Festkörperelektronik, Berlin
Next-generation electronic and photonic devices require advanced materials with tailored properties. The orthorhombic κ-phase of Ga2O3 features an ultrawide bandgap around 5 eV, a large spontaneous polarization along the c-axis and ferroelectric behaviour. A major obstacle for device applications based on κ-Ga2O3 is the formation of rotational domains. Established growth techniques like MBE, MOVPE, PLD and mist CVD have so far only produced rotational-domain samples, where orthorhombic domains with sizes up to 200 nm align along three preferential directions that are 120∘-rotated with respect to each other. Most recently, the growth of single-domain κ-Ga2O3 on orthorhombic ε-GaFeO3 was demonstrated by mist CVD, resulting in a lattice mismatch as low as 1%. We present comprehensive Raman spectra of single-domain κ-Ga2O3, using a set of dedicated polarization geometries to resolve more than 100 of the 117 optical Raman-active modes experimentally. Moreover, we present the angular dependent Raman scattering intensities for excitation of the c-plane, proving the single-domain orthorhombic nature of the investigated thin film.
Keywords: Gallium oxide; Raman spectroscopy