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HL: Fachverband Halbleiterphysik
HL 9: Focus Session: Oxide Semiconductors for Novel Devices II
HL 9.3: Talk
Monday, April 1, 2019, 15:30–15:45, H34
Transport Properties and Finite Size Effects in β-Ga2O3 Thin Films — •Robin Ahrling1, Johannes Boy1, Martin Handwerg1, Olivio Chiatti1, Rüdiger Mitdank1, Zbigniew Galazka2, Günter Wagner2, and Saskia F. Fischer1 — 1Novel Materials Group, Humboldt-Universität zu Berlin, 10099 Berlin, Germany — 2Leibniz Institute for Crystal Growth, 12489 Germany
As a wide-band gap semiconductor with a high breakthrough field, gallium oxide (Ga2O3) has shown to be a promising material for applications in high power electronics. Here, we investigate the electrical properties of thin films and their dependence on film thickness. The scattering processes in the films may changes drastically with decreasing film thickness. [1]
Homoepitaxially MOVPE-grown monocrystalline Si-doped β-Ga2O3 films (28 - 225 nm thickness) were electrically characterized in a temperature range from 300 K down to 10 K. Van-der-Pauw and Hall-measurements were performed to determine conductivity, Hall density and carrier mobility. Thicker films (>150 nm) show a behavior similar to the bulk. Below 100 nm, a drastic drop of the mobility with decreasing thickness was observed, pointing to an additional surface scattering effect. We find that the commonly applied classical Fuchs-Sondheimer model does not explain the contribution of electron scattering at the film surfaces sufficiently. Instead, by applying an electron wave model by Bergmann, a mobility suppression due to the large de Broglie wavelength in β-Ga2O3 is proposed as a limiting quantum mechanical size effect. [1] R. Ahrling et al., https://arxiv.org/abs/1808.00308