Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster 1
HL 13.12: Poster
Montag, 26. März 2007, 15:00–17:30, Poster A
FIR spectroscopy of nanostructured meandering conducting stripes fabricated by AFM nanolithography — •Steffen Groth, Kevin Rachor, Carsten Graf von Westarp, Tobias Krohn, Nikolai Mecking, and Detlef Heitmann — Institut für angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany
We perform far infrared (FIR) photoconductivity spectroscopy on nanostructured meandering conducting stripes fabricated by atomic force microscope (AFM) nanolithography. For this purpose we have established the technique of anodic oxidation to pattern an oxide barrier directly on a GaAs/AlGaAs shallow high electron mobility transistor heterostructure with a two dimensional electron system (2 DES) confined 35 nm below the surface. This technique enables us to prepare barriers with a geometrical thickness of less than 200 nm and lateral structures of different geometry and size down to 300 nm width and up to 180 µm long. The conducting stripe width is furthermore tuneable by sweeping the applied gate voltage. The measurements on the nano Hall bars were performed in a He3 cryostat at a sample temperature of 300 mK in a magnetic field up to 8 T. Transport measurements in the conducting stripes show typical behaviour of 1D subbands. In FIR spectroscopy we observe confined plasmon modes. We have also patterned a line of resonators with accurately defined geometry. Resonances depending on the size of the resonators are predicted for exitation by FIR radiation.
The Authors thank the DFG for support through the SFB 508.