Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 48: Poster 2
HL 48.69: Poster
Donnerstag, 26. März 2009, 15:00–17:30, P2
Electronic transport in InAs nanowires controlled by high-k dielectric gates — •Karl Weis1,2, Sergio Estévez Hernández1,2, Mihail Ion Lepsa1,2, Masashi Akabori1,2, Kamil Sladek1,2, Stefan Trellenkamp1,2, Jürgen Schubert1,2, Thomas Schäpers1,2, Hilde Hardtdegen1,2, and Detlev Grützmacher1,2 — 1Institute of Bio- and Nanosystems (IBN-1), Research Centre Jülich, 52425 Jülich, Germany — 2JARA, Fundamentals of Future Information Technology
Quantum dots in semiconductor nanowires are promising candidates for the realization of quantum bits. It is well known that using gate electrodes is a convenient way to form and tune quantum dots.
Here, the electronic transport properties of n-doped InAs nanowires grown by MBE and MOVPE are examined. For a sample of 22 wires, the length and diameter are (1700 ± 400) nm and (170 ± 20) nm, respectively. The tunability of the carrier concentration in the conductive channel is compared for different gate geometries, e. g. fingers or nearly wrapping gates. Furthermore, we investigate if gate performance can be improved by using a high-k dielectric, namely GdScO3, instead of SiO2. Four-terminal transport measurements are performed both at room temperature and at low temperatures down to 300 mK.
Preliminary field effect transistor measurements were performed at room temperature for the aforesaid sample of 22 wires. We used a SiO2 back gate, varied the gate voltage and measured the drain current. At a source-drain bias of 0.1 V, the pinch-off voltage was Uth=(−40 ± 20) V and the maximum transconductance gm=(1.6 ± 0.8)× 10−6 S.