Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 28: Poster Session: Graphen; Transport properties; Transport in high magnetic fields / Quantum Hall effect; Metal-semiconductor hybrid systems

HL 28.17: Poster

Montag, 11. März 2013, 16:00–20:00, Poster A

Mobility Studies on High Electron Mobility Structures — •Christian Schulte-Braucks, Arne Ludwig, and Andreas D. Wieck — Angewandte Festkörperphysik, Ruhr-Universität Bochum

Two Dimensional Electron Gases in modulation doped High-Electron-Mobility-Transistor-Structures (HEMT) have huge potential in current and prospect research and application. Therefore, a good understanding of properties and scattering processes depending on the sample structure is essential to design samples with desired characteristics such as high electron mobility. A systematic study of Hall-mobility (µ) depending on 2D charge carrier concentration (n) of Molecular-Epitaxy-grown δ-doped GaAs−AlGaAs-HEMTs is in progress. There are two aspects which are focussed on intensively. First varying structural aspects such as spacer thickness, material composition and doping. Second, changing measurement parameters such as sample current and illumination intensity. n has been tuned by succsessive illumination, exploiting persistent photo effect in DX-centres and measurements are planned to be compared by tuning n by Gate bias. Moreover, Shubnikov-de-Haas-Oscillations are projected to get access to the occupation of subbands, the existence of parallel conductance and scattering mechanisms. A power function law µ ∝ n^α where α depends on the spacer thickness has been observed, which can be assigned to remote impurity scattering. In congruence with [1] α is approximately 0.6 but contradictory to [2] increases with increasing spacer thickness.
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