Dresden 2003 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 31: Quantenpunkte und -dr
ähte: Herstellung und Charakterisierung
HL 31.1: Vortrag
Mittwoch, 26. März 2003, 14:30–14:45, BEY/154
InAs quantum dots grown on the GaAs(113)A and B surfaces: a comparative STM study — •Yevgeniy Temko, Takayuki Suzuki, and Karl Jacobi — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin
InAs quantum dots (QDs) were grown by molecular beam epitaxy on GaAs(113)A and B surfaces which exhibit the same crystallographic orientation but different atomic termination. By atomically resolved in-situ scanning tunnelling microscopy we determine the main bounding facets on the QDs. On both substrates the QDs are terminated by {110}-, {111}-surfaces and a rounded region formed by vicinal (001) stacking. Besides this similarity there are also differences: On the (113)A substrate the QDs shape is elongated in the direction [332] whereas the QDs on the GaAs(113)B are rather round [1,2]. The main part of the QDs on GaAs(113)B sits on a flat base formed by high-index (135)B and (112)B surfaces whereas there are no connection facets between the QDs and the (113)A substrate. The size distribution of the islands on the B face is sharper then on the A face. The different size distributions are related to the different morphology of the substrates before QD formation. The differences in shape and size are discussed in terms of facet growth kinetics influenced by site-dependent dissociation of incoming As2 molecules.
[1] T. Suzuki, Y. Temko, and K. Jacobi, Appl. Phys. Lett. 80, 4744 (2002).
[2] Y. Temko, T. Suzuki, and K. Jacobi, submitted to Appl. Phys. Lett..