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Polarization effects in semiconductor superlattices

The polarization dependence of the photoluminescence of GaAs-AlAs superlattices with different well and barrier widths has been investigated. In wide-well superlattices (10-15 nm) the luminescence signal of free excitons has the largest degree of polarization (20-25%). In short-period superlattices, however, the recombination is dominated by indirect, localized excitons (X- Gamma ), which are exposed to anisotropic perturbations along the (110) crystallographic axis. This results in an anomalous detection angle dependence of the polarization.