Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 13: Oxide Semiconductors for Novel Devices (Focussed Session): Session III

DS 13.1: Hauptvortrag

Dienstag, 13. März 2018, 09:30–10:00, E 020

Electron transport in beta-gallium oxide — •Rebecca L. Peterson¹, Zumrad Kabilova¹, and Cagliyan Kurdak² — ¹Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan, USA — ²Department of Physics, University of Michigan, Ann Arbor, Michigan, USA

The sesquioxide semiconductor gallium oxide is currently drawing attention for power electronics and deep ultraviolet optoelectronics applications, due to its ultra-wide bandgap. Gallium oxide has several crystal polytypes. The stable beta-phase has a bandgap of approximately 4.8 eV, a monoclinic crystalline structure, and bulk substrates are commercially available. Here, we present our experimental and theoretical work on charge transport in bulk (010) β−Ga₂O₃, in which the extrinsic tin doping of 10¹⁸ cm⁻³ is close to the Mott metal-insulator transition point. A peak electron mobility of 95 cm²V⁻¹s⁻¹ was measured at 185K. Across a wide temperature range, a two-band conduction model applies, consisting of a impurity band in parallel with the conduction band, as was observed previously for n⁺⁺ (201) β−Ga₂O₃ [1]. At low temperature, we find that conduction is via variable-range hoping through the impurity band. At high temperatures, phonon scattering of conduction band electrons dominates, similar to lightly-doped (100)  β−Ga₂O₃ [2]. This work was supported by DARPA/SPAWAR under award N66001-14-1-4046. [1] T. Oishi, K. Harada, Y. Koga, and M. Kasu: Japan. J. Appl. Phys. 55, (2016) 030305; [2] A. Parisini and R. Fornari, Semicond. Sci. Technol. 31, (2016) 035023.