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HL: Fachverband Halbleiterphysik
HL 25: Oxide Semiconductors I
HL 25.6: Vortrag
Mittwoch, 20. März 2024, 10:45–11:00, ER 325
Determination of self-trapped exciton emission bands in Ga2O3 polymorphs — •Nima Hajizadeh1, Benjamin M. Janzen1, Moritz Meissner1, Marcella N. Marggraf1, Conrad V. Hartung1, Alwin Wüthrich1, Nils Bernhardt1, Felix Nippert1, and Markus R. Wagner2,1 — 1Technische Universität Berlin, Institute of Solid State Physics — 2Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V.
Several temperature and excitation dependent photoluminescence (PL) and excitation (PLE) spectra are published for the thermodynamically stable β phase. In addition, a large number of theoretical calculations allow the assignment of observed emission bands. Accordingly, the UV bands in β-Ga2O3 are associated with the recombination of a self trapped hole (STH) and bound electrons. Such clear experimental assignments of optical bands for the different Ga2O3 polymorphs do not yet exist. Using temperature-dependent PL and PLE spectroscopy, we provide a study to investigate emission bands of monoclinic β-, orthorhombic κ-, rhombohedral α-, defective-spinel γ- and cubic bixbyite δ-Ga2O3 as a function of excitation and temperature. Based on these spectra, a possible experimental identification of STH emission bands for different Ga2O3 polymorphs will be discussed. Furthermore, this evaluation may be supported by a correlation between the experimental stokeshifts and the theoretically calculated self-trapping energies in the literature, which would allow the detection and energetic determination of these excitons.
Keywords: Gallium oxide; Spectroscopy; Self trapped holes; Exciton