Shape transformations of self-assembled InAs quantum dots are observed after overgrowth with GaAs or AlAs and a subsequent growth interruption. The structural, optical, and electronic properties of shape transformed self-assembled InAs quantum dots (STQD) are studied with atomic force microscopy, photoluminescence (PL), and deep level transient spectroscopy, respectively. We find a strong influence of the capping procedure on both the shape of the STQDs as well as the resulting energy level structure. (c) 2006 Elsevier B.V. All rights reserved.