Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 62: Quantum Dots and Wires: Transport Properties I (mainly Quantum Wires)

HL 62.4: Talk

Wednesday, March 28, 2012, 15:45–16:00, EW 203

Electrical properties of catalyst-free MBE grown InAs nanowires — •Philipp Geselbracht¹, Stefanie Bolte¹, Dance Spirkoska¹, Simon Hertenberger¹, Verena Hintermayr¹, Markus Döblinger², Max Bichler¹, Gerhard Abstreiter^{1, 3}, and Gregor Koblmüller¹ — ¹Walter Schottky Institut and Physik Department, TU München, Garching, Germany — ²Department of Chemistry, Ludwig-Maxililians-Universität, Munich, Germany — ³TUM Institute for Advanced Study, Garching, Germany

In this work we report on the electrical properties of catalyst-free, nominally undoped InAs nanowires grown on Si substrates using ultra-pure, solid source molecular beam epitaxy (MBE). By applying a wide range of growth parameters we have obtained nanowires with different amount of zinc-blende and wurtzite segments in their crystal structure as investigated by Transmission Electron Microscopy (TEM). We have fabricated planar field effect transistor devices both in global back gate and top gate geometry. From transmission line method, as well as four point I-V measurements we have determined the contact resistance to be <1 kOhm . Our devices are characterized with large ON/OFF ratio and mobility in the range of 2000 cm2/Vs at room temperature confirming the worthiness of the catalyst-free growth mode. Additionally, we will discuss the effect of the gate geometry on the characteristics of the field effect devices and give first insight into wrapped gate devices