SKM 2021 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 11: Focus Session: Functional Metal Oxides for Novel Applications and Devices
HL 11.7: Vortrag
Dienstag, 28. September 2021, 16:15–16:30, H4
Electronic Raman scattering study of Ir4+ ions in beta-Ga2O3 — •Palvan Seyidov1, Manfred Ramsteiner2, Zbigniew Galazka1, and Klaus Irmscher1 — 1Leibniz-Institut für Kristallzüchtung, Max- Born-Str. 2, 12489 Berlin, Germany — 2Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e.V., Hausvogteiplatz 5-7, 10117 Berlin, Germany
Currently, beta-Ga2O3 is in the research focus as a material for power electronic devices because of its anticipated high electric break down field (~8MV/cm). For such applications, unintentional impurities in bulk crystals can lead to detrimental effects in device performance. Here we study electronic Raman scattering (ERS) of Ir4+ ions in bulk crystals grown by the Czochralski method. The optical excitation energy was varied between 1.95eV to 3.81eV by using Ar+ ion and HeCd lasers. Conventionally, Raman scattering is used to investigate vibrational modes of molecules and crystals. In contrast, inelastic light scattering due to electronic transitions can be studied by ERS. We observed an ERS feature at 5152 cm-1 (1.94 um, 0.639 eV) in room-temperature spectra from bulk beta-Ga2O3. The observed spectral feature is attributed to Ir4+ ions incorporated on Ga sites and assigned to an intra-center d-d transition within the t2g orbitals. The ERS efficiency is found to strongly depend on the photon energy used for optical excitation. The observed maximum at 2.8 eV can be explained by a resonance enhancement involving an electron transfer from Ir3+ to the conduction band at ~2.2 eV and an Ir4+ intra-center transition at ~0.6 eV.