Resonant Raman scattering in GaAs-Ga1−xAlxAs quantum wells in an electric field

We apply resonant Raman scattering for studying the effect of an electric field on the electronic structure of GaAs-${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Al}}_{\mathrm{x}}$As quantum wells. The evolution with the field of the intensities and frequencies of both ‘‘allowed’’ and ‘‘forbidden’’ transitions is measured. In order to show the advantages of this technique over the ones currently used, we compare it with photoluminescence excitation spectra of the same system. The analysis of the experimental results is performed by a tight-binding calculation which includes the effect of the electric field on the mixing between different electronic states.