Enhancement of donor electronic Raman scattering in CdS

Resonance enhancements of electronic Raman scattering due to shallow donors (substitutional Cl and F) in CdS are reported. The experimental results are interpreted quantitatively in terms of "two-step" electronic Raman processes. The resonant intermediate states are the top valence bands and bottom conduction band of CdS and also excitons bound to the donors. The relative contributions of the valence bands to the scattering cross section have been calculated with Hopfield's quasicubic model. It is demonstrated that by utilizing resonance enhancements donor electronic Raman scattering can be observed with only a few milliwatts of laser power in CdS containing less than ${10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$ of donor atoms.