Piezomodulated reflectance (PzR) spectra at 77 and 300K have been measured for InAs/In0.15Ga0.85As dots-in-a-well and a conventional InAs/GaAs quantum dots. The optical features of both samples were well resolved and confirmed by photoluminescence results. Numerical calculations are in good agreement with the experimental results. The transitions in sandwiched structure formed by InAs wetting layer and ln(0.15)Ga(0.85)As/GaAs quantum well supports the model of strain-driven alloy decomposition. The abnormal intensity between heavy-hole-type and light-hole-type transition of such sandwiched structure in PzR spectra has been discussed in terms of increased hydrostatic strain in In(0.15)Ga0(.85)As/GaAs quantum well. (c) 2006 Elsevier B.V. All rights reserved.