Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 26: Poster Session: Heterostructures - Preparation and Characterization - Impurities / Amorphous Semiconductors
HL 26.5: Poster
Montag, 26. März 2012, 16:00–19:00, Poster D
Noise spectroscopy of two-dimensional-electron systems in GaAs/AlGaAs heterostructures — •Berit Körbitzer1, Pintu Das1, Y. Ohno2, H. Ohno2, and Jens Müller1 — 1Goethe-Universität, Frankfurt am Main, Germany — 2Tohoku University, Sendai, Japan
Because of their high mobility, two-dimensional-electron gases (2DEG) formed at the heterostructure interface of GaAs/AlGaAs are often used as high-resolution Hall magnetometers. Since the noise level has a considerable influence on the sensitivity of these sensors, it is important to study their noise characteristics. Therefore, we have investigated the low-frequency dynamics of charge carriers in such 2DEGs in the temperature range of 10 K to 300 K by using fluctuation spectroscopy. This technique allows to gain information about the energetics of different defects, as e.g. the well-known DX centers [1,2].
In this work we have measured resistance and Hall-voltage noise as a function of the size of Hall structures, which were prepared by standard photolithography techniques. We will also discuss the dependence of the fluctuation properties on the gate voltage.
[1] Jens Müller et al., PRL 96, 186601 (2006)
[2] Jens Müller et al., PRB 74, 125310 (2006)