Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 11: Poster 1
HL 11.51: Poster
Montag, 11. März 2002, 17:00–19:30, Poster A
Influence of processing parameters on the transport properties of quantum point contacts — •G. Apetrii1, S.F. Fischer1, U. Kunze1, D. Reuter2 und A.D. Wieck2 — 1Lehrstuhl für Werkstoffe der Elektrotechnik, Ruhr-Universität Bochum, D-44780 Bochum — 2Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum
High quality quantum point contacts (QPC) were fabricated by lateral confinement of the two dimensional electron gas (2DEG) contained in a GaAs/AlxGa1−xAs selectively doped heterostructure. Atomic force microscope lithography and subsequent wet chemical etching [1] are proven to be a reliable method to create the narrow constriction defining the QPCs. We show that the lateral confining potential can be systematically modified by variation of the nominal lithographical distances and/or the etching parameters (time, dilution). Plots of the differential conductance measured at 4.2 K as a function of the gate voltage show a corresponding shift of the threshold voltage (VT) as well as a variation of the width of the quantized conductance plateaus. With decreasing the 1D-channel width VT and the plateau widths increase. In order to characterize the confining potential we evaluate the one dimensional subband separations using grey scale plots of the transconductance as a function of the gate voltage and the dc drain voltage.
[1] B. Klehn, U. Kunze, J. Appl. Phys. 85, 3879 (1999)