We have investigated the nucleation and ripening of pairs of InAs/GaAs quantum dot layers separated by thin (220 mn) GaAs spacer layers. Reflection high energy electron diffraction (RHEED) measurements show that the 2D-3D transition in the second layer can occur for less than I monolayer deposition of InAs. Immediately after the islanding transition in the second layer chevrons were observed with included angles as low as 20degrees and this angle was seen to increase continuously to 45 +/- 2degrees as more material was deposited, Atomic force microscopy showed the dot density in both layers to be the same. It is proposed that surface morphology can radically alter processes that determine the nucleation and ripening of the 3D islands. (C) 2002 Elsevier Science B.V. All rights reserved.