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

Abstract

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 /spl Aring/ the SLs grown on faceted [311]A GaAs substrates contain periodic corrugated GaAs and AlAs layers. The period of corrugation is 32/spl Aring/ along the [011~] direction, the height of corrugation is 10.2 /spl Aring/. 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 /spl Aring/. Later the 10.2 /spl Aring/ 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 /spl Aring/ 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.