InP nano-template structures with (0 0 1) top surfaces and atomically smooth crystallographic side facets have been controllably fabricated in situ for site-selective quantum dot nucleation studies using selective area chemical beam epitaxy. Deposition of a sub-critical layer of InAs on the nano-templates results in the nucleation of self-assembled quantum dots (SADs) exclusively on the (0 0 1) top surface as a result of the diffusion of InAs from the side facets onto the (0 0 1) surface. As the dimensions of the (0 0 1) top surface are decreased from 1000 down to 50 nm or less, scanning electron microscopy reveals a gradual increase in the spatial correlation between SADs, whilst linear arrays of uniform SADs are formed for dimensions below 200 nm. In addition, the density of SADs can be controllably varied by more than two orders of magnitude on the same sample by appropriate choice of nano-template dimension. (C) 2002 Elsevier Science B.V. All rights reserved.