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HL: Fachverband Halbleiterphysik
HL 72: Focus Session: Functional Metal Oxides for Novel Applications and Devices III (joint session HL/DS)
HL 72.5: Vortrag
Donnerstag, 19. März 2020, 16:00–16:15, POT 81
Electric and Thermoelectric Properties of ZnGa2O4 Bulk Crystals — •Johannes Boy1, Martin Handwerg1, Rüdiger Mitdank1, Zbigniew Galazka2, and Saskia F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany — 2Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, 12489 Berlin, Germany
In the past years, intense research has been done in the field of oxide semiconductor materials, which are promising candidates for the design of novel high power devices, optoelectronics and sensing systems due to their wide bandgap.
ZnGa2O4 is a transparent material of blue coloration, with a high bandgap Eg=4.6 eV at room temperature [1]. The majority charge carrier type is n-type. Electron mobilities up to 100 cm2/Vs with charge carrier concentrations in the order of 1018 - 1019 cm−3 have been reported [1].
In this work, we manufactured microlabs on the chip [2] to investigate the temperature dependence of the Seebeck coefficient S, Hall charge carrier density n and mobility µ between T=10 K and T=320 K. At high bath temperatures T>230 K, the scattering is determined by electron-phonon-interaction. At low bath temperatures (between 10 and 150 K) we observe a temperature-independent maximum, which can be explained by electrons interacting with ionized impurities. The room temperature Seebeck coefficient is S(300 K)=(−120±3) µV/K and decreases with decreasing bath temperature.[1] Z. Galazka, et al.; APL Materials 7, 022512 (2019).
[2] J. Boy, et al.; APL Materials 7, 022526 (2019).