  Modulated electroreflectance spectroscopy $\Delta R/R$ of semiconductor
self-assembled quantum dots is investigated. The structure is modeled as dots
with lens shape geometry and circular cross section. A microscopic description
of the electroreflectance spectrum and optical response in terms of an external
electric field (${\bf F}$) and lens geometry have been considered. The field
and lens symmetry dependence of all experimental parameters involved in the
$\Delta R/R$ spectrum have been considered. Using the effective mass formalism
the energies and the electronic states as a function of ${\bf F}$ and dot
parameters are calculated. Also, in the framework of the strongly confined
regime general expressions for the excitonic binding energies are reported.
Optical selection rules are derived in the cases of the light wave vector
perpendicular and parallel to $% {\bf F}$. Detailed calculation of the Seraphin
coefficients and electroreflectance spectrum are performed for the InAs and
CdSe nanostructures. Calculations show good agreement with measurements
recently performed on CdSe/ZnSe when statistical distribution on size is
considered, explaining the main observed characteristic in the
electroreflectance spectra.
