Field-enhanced Stokes shifts in tensilely strained carbon-based quantum wells

Abstract
A large, rigid downward shift of excitonic luminescence peak energies was observed with increasing transverse electric field in tensilely strained Si 1−y C y / Si(001) symmetric quantum wells, as opposed to theoretical calculations predicting a blueshift due to exciton weakening, which more than balances the redshift due to quantum-confined Stark effects. The observed anomalies are interpreted in terms of field-enhanced Stokes shifts which occur due to carrier relaxation in an inhomogeneously distributed potential of the grown-in Si 1−y C y / Si interfaces.