Regensburg 1998 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 2: Poster I
HL 2.140: Poster
Montag, 23. März 1998, 10:30–19:00, A
InAs Self-Assembled Quantum Dots as Controlled Scattering Centers near a 2DEG — •E. Ribeiro1, E. Müller2, T. Heinzel1, K. Ensslin1,2, G. Medeiros-Ribeiro3, and P. M. Petroff3 — 1Lab. für Festkörperphysik - ETH Zürich, 8093 Zurich, Switzerland — 2Paul Scherrer Institut, 5232 Villigen, Switzerland — 3University of California, Santa Barbara, California 93106
We investigate the influence of InAs self-assembled quantum dots on the transport properties of a two-dimensional electron gas. The dot density varies across the wafer. The mobility vs. carrier density traces for a series of samples with various dot densities show that for a given carrier density the mobility drops drastically with increasing dot density. Dot densities extracted from a scattering model in which the dots act as randomly-distributed charged impurities close to the interface are comparable to what is found by TEM. For high dot density samples, the observed mobility saturation with carrier density might indicate that the separation among the dots has reached the screening length for the electrons, so that the dominant scattering potential can no longer be screened efficiently.