Strained InAs nanostructures self-organised on high-index InP(113)B

We investigated self-assembled InAs islands grown on In0.52Al0.48As/InP(113 )B by molecular beam epitaxy (MBE) using in-sim reflection high-energy elec tron diffraction (RHEED) and in-situ scanning tunnelling microscopy (STM). For a deposition of 3 monolayers (MLs) of InAs, the STM topography revealed a high density of well-organised hexagonal facetted dots. The dots are tru ncated (height similar to 3 nm) and elongated along the [1 1 0] direction. Their typical base dimensions are approximately 48 and 19 nm. The angles be tween facet orientation and crystal direction were accurately deduced from RHEED patterns. From these structural characterisations, the dot shape and formation mechanism are discussed using a standard scheme based on surface energy minimisation. A direct correlation is found between the dot shape an d the surface reconstruction unit cell. (C) 2000 Elsevier Science B.V. All rights reserved.