It was demonstrated that ZnSe/ZnS quantum dots (QDs) could undergo structural transitions from 3D islands to 2D layer during growth interruption (GI) under hydrogen flows. In addition to the structural transition, a complex ripening process of the ZnSe QDs were observed together. Temperature-dependent photoluminescence (PL) measurements show that the ZnSe QDs turned into a quasi-2D layer, when the GI reached 60 s. PL lineshape evolution through the GI suggests two ripening regimes for the ZnSe QDs, which are in striking agreement with those for CdSe QDs. (c) 2006 Elsevier B.V. All rights reserved.