RHEED studies of nucleation of Ge islands on Si(001) and optical properties of ultra-small Ge quantum dots

The initial stages of Ge growth on the Si(001)-(2 x 1) surface have been studied by using a RHEED pattern zero-streak profile analysis technique. Thicknesses for {105} and {113} facets formation, corresponding to the nucleation of coherent 'hut'-clusters and dislocated 'dome' three-dimensional (3D) islands respectively, were determined in a growth temperature range of about 200-600 degrees C. Multilayer structures containing ultra-small Ge quantum dots (QDs) with a plane size of about 10 nm and a height of 1.5 nm have been studied by photoluminescence (PL). PL bands assigned to QDs show an intensity comparable to data in the literature, but a band width five times smaller. (C) 2000 Elsevier Science S.A. All rights reserved.