Berlin 2005 – scientific programme
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HL: Halbleiterphysik
HL 16: Poster Ia
HL 16.19: Poster
Friday, March 4, 2005, 16:30–19:00, Poster TU E
In-plane tunneling spectroscopy of low-dimensional electron systems in a GaAs/AlGaAs heterostructure — •J.-L. Deborde1, S. F. Fischer1, U. Kunze1, D. Reuter2, and A. D. Wieck2 — 1Werkstoffe and Nanoelektronik, Ruhr-Universität Bochum — 2Angewandte Festkörperphysik, Ruhr-Universität Bochum
The use of tunneling spectroscopy between low-dimensional electron systems is of great interest to observe spectral features such as bandstructure effects or electron mode coupling. Using atomic force microscope (AFM) lithography, we produced a smooth potential barrier in a GaAs/AlGaAs heterostructure allowing in-plane tunneling in a two-dimensional electron gas (2DEG) as electrodes. The application of a bias across the barrier revealed Fermi-edge effects in the tunneling spectrum. Considering this AFM fabricated tunneling barrier, we aim to implement an in-plane electron directional coupler. Devices consisting of two parallel quantum wires (QWs) separated by a tunneling barrier were prepared by means of a combination of electron beam lithography and AFM lithography techniques. The electron density inside each one-dimensional electron waveguide (1DEWG) is controlled by in-plane gates whereas the height of the potential barrier is tuned by an electron-beam evaporated Schottky top gate. The conductance of the 1DEWGs show steps quantized with 2e2/h as characteristic of one-dimensional transport. Experiments are expected to reveal tunnel coupling between the two 1DEWGs.