Origin of the stokes shift in semiconductor quantum wells



Excitonic energy levels have been calculated in CdTe quantum wells with Cd1−xMnxTe barriers. It has been shown that the introduction of small-scale (relative to the exciton Bohr radius) interface disorder, which either preserves or breaks the inversion symmetry, can produce appreciable Stokes shifts between optical absorption and emission and that the associated line-widths can remain narrow. A criterion for the existence of high-quality interfaces, based on optical spectra, is described.