Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 48: Quantum dots and wires: preparation and characterization II
HL 48.5: Vortrag
Donnerstag, 29. März 2007, 17:15–17:30, H13
Influence of the electron injection energy on ballistic transport in nanoscale GaAs/AlGaAs cross junctions — •Matthias Wiemann1, Ayhan Cetinkaya1, Ulrich Wieser1, Ulrich Kunze1, Dirk Reuter2, and Andreas Wieck2 — 1Werkstoffe und Nanoelektronik - Ruhr-Universität Bochum, D-44780 Bochum, Germany — 2Angewandte Festkörperphysik - Ruhr-Universität Bochum, D-44780 Bochum, Germany
Ballistic electron transport is studied in a modified nanoscale cross junction prepared from a high-mobility GaAs/AlGaAs heterostructure. The device is defined by combining electron-beam lithography with standard photo lithography and is transferred by wet-chemical etching. The lateral geometry is given by a central orthogonal cross junction and two additional branches which orthogonally merge in the vertical bar on each side of the central junction. A potential barrier is formed by a nanoscale Schottky top-gate finger, which crosses the vertical bar near the central cross junction. The barrier enables to vary the kinetic energy of injected electrons. If an input bias is applied between the vertical bar embedding the barrier and an orthogonal lead of the central cross junction, negative bend resistance is found in the nonlocal I-V transfer characteristics. In this configuration V describes the potential difference between the voltage probes opposite to the current leads. If the transfer voltage is detected between the barrier free part of the vertical bar and its neighboring branch, gate-voltage dependent nonlinearities are observed.