Polarization anisotropy of photoluminescence in corrugated and flat GaAs/AlAs short-period superlattices, grown on faceted [311]A and flat [311]B, [100] GaAs substrates

The flat and corrugated GaAs/AlAs short-period superlattices (SLs) were studied by polarization resolved-photoluminescence. The phenomenon of photoluminescence polarization anisotropy was observed. The polarization nature is explained by both valence band anisotropy and anisotropy associated with interface corrugation in the case of a [311]A corrugated SLs (CSLs). It was determined that for a GaAs layer thickness from 10.2 to 22 Å the SLs grown on faceted [311]A GaAs substrates contain periodic corrugated GaAs and AlAs layers. The period of corrugation is 32Å along the [011~] direction, the height of corrugation is 10.2 Å. This correlates with the model of R. Notzel et al. (1993), and contrasts with the model of M. Wassermeier et al. (1995), where the height of corrugation is 3.4 Å. Later the 10.2 Å interface corrugation of GaAs and AlAs layers in these [311]A SLs was directly observed by TEM. The CSLs with average GaAs layer thickness of less than 10.2 Å exhibited considerably lower polarization anisotropy. In this case GaAs quantum dots were formed. The formation of dots reduces the polarization degree. These results are important for development of CSL-based devices sensitive to polarization and operating at high temperatures.