Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 9: Poster I
HL 9.77: Poster
Montag, 27. März 2006, 15:15–17:45, P3
Detection of impurities in a Coulmb blockade device — •D. Tutuc1, M. C. Rogge1, M. Reinwald2, W. Wegscheider2, and R. J. Haug1 — 1Institut für Festkörperphysik, Abteilung Nanostrukturen, Universität Hannover, Appelstrasse 2, 30167 Hannover — 2Angewandte und Experimentelle Physik, Universität Regensburg, D-93040 Regensburg
In this work we report results on electrical transport in zero and non-zero magnetic field in a multi-terminal quantum dot fabricated by Local Anodic Oxidation (LAO) with an Atomic Force Microscope (AFM). The measurements were performed at low temperatures (approximately 17mK) in a 3He/4He dilution cryostat with magnetic field ranging from 0T to 5T with. In the Coulomb blockade regime we observe charged impurities suppressing the transport through the dot. The measurements are fully reproducible and the effect is also present in the measurements in magnetic field at 1T and 2T. The reproducibility of this effect lets us assume that the impurities are stable and not induced by random telegraph noise. Since magnetic field has almost no detectable effect the impurities seem to be of non-magnetic origin and seem to be situated near the barriers.