Selective excitation of spin-flip Raman scattering from electrons bound to donors in semiconductor quantum well structures

The spin-flip Raman scattering of electrons bound to donors in CdTe/Cd _1-xMn_xTe multiple quantum well structures has been studied. The spin-flip energies are influenced strongly by the competing potentials of the quantum wells and of the donor ion. As a result, the spin-flip energy is a function of the donor position relative to the well centre. Because of resonance effects, the Raman spectra are sensitive to the laser photon energy and the results demonstrate a correlation between the binding energy of the electron to the donor (which determines the Raman shift) and the localization energy of an exciton at the neutral donor (which determines the energy of the Raman resonance). Studies of a structure containing two coupled quantum wells reveal similar effects and lend further support to the model.