Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 2: Topological insulators: mostly structure and electronic structure (with MA/O/TT)
HL 2.1: Talk
Monday, March 31, 2014, 09:45–10:00, POT 051
InAs/GaSb compound quantum wells for electrically tunable topological insulator devices — •Georg Knebl1, Matthias Dallner1, Robert Weih1, Sven Höfling1,2, and Martin Kamp1 — 1Universität Würzburg, Deutschland — 2University of St Andrews, Scotland
InAs/GaSb compound quantum wells (CQW) sandwiched between two AlSb layers and a front/back gate were proposed by Liu et al. [1] to show a topological insulator phase. The advantage of this structure is the possibility to tune the phase transition from a normal to a topological insulator via the front and back gate voltage. In addition, this material combination allows the use of established III/V semiconductor technology for epitaxy and device processing.
We present results on the growth of InAs/GaSb CQWs via molecular beam epitaxy on GaSb and GaAs substrates using different buffers. Furthermore, we will discuss device fabrication on InAs/GaSb layer structures, which requires special care since oxidation or process induced damage can lead to the formation of conducting surface channels. Electrical characterization of Hall bars and the tunability of the transport properties via gates will be reported.
[1] C. Liu, et al., Phys. Rev. Lett. 100, pp. 1-4, (2008)