Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 63: III-V Semiconductors

HL 63.6: Vortrag

Freitag, 26. März 2010, 11:45–12:00, H13

Carbon doped GaAs/AlGaAs heterostructures with high mobility two dimensional hole gas — •Marika Hirmer¹, Dieter Schuh¹, and Werner Wegscheider^{1, 2} — ¹Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D 93040 Regensburg, Germany — ²present address Laboratorium für Festkörperphysik, ETH Zürich, Schafmattstr. 16, 8093 Zürich, Switzerland

Two dimensional hole gases (2DHG) with high carrier mobilities are required for both fundamental research and possible future ultrafast devices.

Here, two different types of GaAs/AlGaAs heterostructures hosting a 2DHG were investigated. The first structure is a GaAs QW embedded in AlGaAs barrier grown by molecular beam epitaxy with carbon-doping only at one side of the QW (single side doped, ssd), while the second structure is similar but with symmetrically arranged doping layers on both sides of the QW (double side doped, dsd).

The ssd-structure shows mobilities up to 1.2*10⁶ cm²/Vs which are achieved only after illumination, while the dsd-structure hosts a 2DHG with mobility up to 1.6*10⁶ cm²/Vs. In addition, mobility and density is not affected by illuminating this sample. Both samples showed distinct Shubnikov-de-Haas oscillations in magnetotransport experiments done at 350mK, indicating the high quality of the material. Further, the influence of different temperature profiles during growth and the influence of the Al content of the barrier Al_xGa_1−xAs on carrier concentration and mobility were investigated.