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HL: Fachverband Halbleiterphysik
HL 6: Quantum dots and wires: preparation and characterization I
HL 6.7: Talk
Monday, March 26, 2007, 12:30–12:45, H15
Guided self assembly of mono- and bi- chain of InAs quantum dots on a cleaved facet — •Emanuele Uccelli1, Dieter Schuh2, Jochen Bauer1, Max Bichler1, Gerhard Abstreiter1, and Anna Fontcuberta i Morral1 — 1Walter Schottky Institute, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany — 2Institut für Angewandte und Experimentelle Physik II, Universität Regensburg, 93040 Regensburg, Germany
Recently, we were able to fabricate long range ordered chains of InAs QDs by combining selective growth with self-assembly (APL 85, 4750 (2004)). InAs growth was realized on a (110) facet consisting of AlAs nanostripes embedded in GaAs, that was obtained by in situ cleaving of a previuosly MBE grown AlAs/GaAs (001) heterostructure. Here, we present an extended phase diagram for the fabrication of QDs arrays, showing under which conditions preferential growth of QDs on the AlAs stripes occurs. We found that the lateral dimensions of the QDs directly reflect the thickness of the underlying AlAs layer, with an onset for the QDs nucleation at AlAs stripe thickness of about 14 nm. The volume and the height of the QDs increases linearly with the stripe thickness. For AlAs stripes thicker than 40 nm, we also observed the formation of double QDs chain on the same stripe depending by the amount of the InAs deposited material. Finally, a comprehensive model is presented, for the understanding of the mechanism of selective nucleation of the single and double QDs chain on the AlAs stripes as a function of the growth conditions. The model gives insight for the mastering of the density and uniformity of the dots arrays.