Polarization anisotropy of photoluminescence in corrugated and flat GaAs/AlAs short-period superlattices

The flat and corrugated GaAs/AlAs short-period superlattices were studied using photoluminescence spectroscopy in a wide temperature range. The phenomenon of photoluminescence polarization anisotropy was observed. The polarization nature is explained by valence band anisotropy in the case of (311 )A corrugated superlattices with a GaAs layer thickness of more than 35 Å. For a thickness of less than 35 Å, the polarization anisotropy is explained by both valence band anisotropy and anisotropy associated with interface corrugation. It was determined that the superlattices grown on faceted (311)A GaAs substrates contain periodic corrugated GaAs and AlAs layers. The period of corrugation is 32 Å along the [01-1] direction, the height of corrugation is 10.2 Å. A blueshift and a redshift of the Γ electron-Γ heavy hole transition were observed. It was found that a blueshift (redshift) should be observed in GaAs/AlAs superlattices when the GaAs layer thickness is smaller (larger) than ~36 Å. The photoluminescence peak position observed for the (311)A GaAs/AlAs superlattices with corrugation was shifted to higher energy region and the photoluminescence intensity was an order of magnitude higher than for the (311)A superlattices without corrugation with the same average thickness of GaAs layers. These results are important for development of CSL-based devices (such as lasers, light-emitting diodes, photo-detectors, etc.) operating in a wide temperature range