Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 107: Poster: Emerging oxide semiconductors / Oxides other than ZnO and its relatives

HL 107.19: Poster

Donnerstag, 3. April 2014, 17:00–20:00, P1

Raman scattering in (In,Ga)₂O₃ thin films — •Christian Kranert, Christian Dähne, Jörg Lenzner, Holger von Wenckstern, Rüdiger Schmidt-Grund, and Marius Grundmann — Universität Leipzig, Institut für Experimentelle Physik II, Semiconductor Physics Group, Leipzig, Germany

Raman scattering in the (In,Ga)₂O₃ material system greatly benefits from excitation with ultraviolet (UV) laser light. For pure β-Ga₂O₃ and Ga-rich alloys with the same crystal structure, the increased scattering cross section due to the high photon energy enhances the feasibility of Raman measurements carried out on thin films with thicknesses down to 100 nm or even less. In case of pure In₂O₃, resonant excitation near the band gap enables the observation of most Raman active modes, which have not yet been reported.

In this contribution, we make use of the above mentioned advantages of UV excitation to characterize the (In,Ga)₂O₃ material system by Raman scattering. We present the dependence of the energy of several phonon modes on the indium concentration in the Ga-rich β-phase. The obtained results allow a precise determination of the composition based on the Raman spectrum. We further give the energy and symmetry of previously not observed phonon modes in bixbyite-type In₂O₃. These show a distinct sensitivity to the growth parameters. Consequently, UV Raman scattering appears to be a promising method for the characterization of such films.