Evolution of InAs quantum dots grown on cross‐hatch substrates

Abstract

AbstractInAs quantum dots (QDs) are grown on In0.2Ga0.8As/GaAs cross‐hatch layer by molecular beam epitaxy. The self‐assembled QDs form with the deposition of approximately 0.8 monolayer (ML) of InAs. The QDs distribute on the cross‐hatch surface unevenly: more are found along the [1‐10] crystallographic direction than the orthogonal [110] direction, while there exists even lower density of QDs on the flat areas. Height analyses indicate that QDs first form at the hatches' intersections, then they form along the [1‐10] direction, the [110] direction, and on the flat areas, respectively. This orderly evolution of QDs is attributed to the characteristic strain distribution of the cross‐hatch surface, giving rise to position‐ and orientation‐dependent critical thickness for QD formation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)