Strain tensor and electron and hole spectra in self-assembled InGaAs/GaAs and SiGe/Si quantum dots

In this paper we examine the strain tensor in quantum dot structures produced by high-strain single-step epitaxy using a valence force field model. We use an eight-band k.p formalism to find the electronic spectra in the highly strained dots. Results obtained for the conduction band spectra using the effective mass approach are shown to have serious errors, This is particularly true for excited states in the conduction band, The dependence of the electronic spectra on the quantum dot size and shape is also reported along with comparisons with published experimental results. Optical transition strengths for inter-subband levels are also calculated. (C) 1998 Elsevier Science B.V. All rights reserved.