We used photo luminescence (PL), photo reflectance (PR) spectroscopy and transmission electron microscopy (TEM) to investigate the effects of high potential barriers on the optical and structural characteristic of InAs quantum dots (QDs). A sample with regular InAs QDs on GaAs was grown as a reference using molecular beam epitaxy. Another InAs QD sample was embedded in a single AlGaAs barrier. A sample with a GaAs/AlGaAs superlattice barrier was compared with the single AlGaAs layer sample. Our results showed that the emission wavelength of the QDs was effectively tailored by the high potential barriers. The optical properties of the sample with QDs embedded in GaAs/AlGaAs superlattices were better than those of the sample with the QDs embedded in a single layer of AlGaAs. We believe that this was because the GaAs/AlGaAs superlattice is effective in preventing the generation of defects. (C) 2004 Elsevier B.V. All rights reserved.