Photoreflectance spectroscopy of vertically coupled InGaAs/GaAs double quantum dots

Photoreflectance and high excitation photoluminescence spectra have been measured at 10 K for In0.6Ga0.4As/GaAs double quantum dot structures with various thicknesses of the GaAs separating layer. Several transitions between split states, due to the dot-dot and wetting layer well-well interaction, have been observed. The transitions have been identified using the results of the effective mass approximation calculations for double quantum wells and lens-shaped double quantum dots. The splitting energy of the quantum dot transitions has been obtained as function of the GaAs barrier width. (C) 2001 Elsevier Science Ltd. All rights reserved.