Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 31: Poster I: Devices, Quantum Dots and Quantum Wires

HL 31.26: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D1

Scattering of hot electrons in 1D versus 2D — •Daniela Taubert¹, Georg Schinner¹, Hans-Peter Tranitz², Werner Wegscheider³, and Stefan Ludwig¹ — ¹Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany — ²Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany — ³Solid State Physics Laboratory, ETH Zurich, 8093 Zurich, Switzerland

We measure the energy relaxation of excited electrons in high mobility two-dimensional electron systems (2DES). If hot electrons scatter with the cold degenerate Fermi sea, they exite additional electrons which leave behind conduction band holes. In a suitable three-terminal device, injection into one contact followed by separation of electrons and holes by a gate-defined barrier can lead to an amplification of the injected electron current. From this amplification effect, we extract information about the scattering processes in form of e.g. energy and power dependence.

By applying a perpendicular magnetic field, we observe the crossover from scattering in two dimensions to electrons moving in 1D edge channels.

For energies above 36 meV, emission of optical phonons becomes a relevant scattering process. In a high magnetic field, electron-electron scattering is reduced but electrons relax very efficiently by emission of optical phonons, which can be observed as a periodic reduction of the amplification effect with a period of 36 meV, up to 11th order.