The growth of AlSb quantum dots (QDs) on Si(1 0 0) substrates by molecular beam epitaxy (MBE) was investigated using reflection high-energy electron diffraction and atomic force microscopy (AFM), with varying the growth rate and Sb-4/Al flux ratio. The thickness of the AlSb wetting layer (WL) was found to be independent of the Sb-4/Al flux ratio and AlSb growth rate. At 540 degrees C, the thickness of the AlSb WL was about 0.3 monolayer regardless of the growth rate and flux ratio. AFM images showed that the size and density of AlSb QDs strongly depended on the growth rate and flux ratio. These results provide important information on the formation process of AlSb QDs on Si substrates. (c) 2006 Elsevier B.V. All rights reserved.