Unstrained GaAs Quantum Dashes Grown on GaAs(001) Substrates by Droplet Epitaxy

We report the formation of GaAs quantum dashes on GaAs(001) substrates using droplet epitaxy. Isotropic GaAs quantum dots at low temperature become elongated as the uncapped annealing temperature increases, resulting in GaAs quantum dashes. Emission from the dots (dashes) shows a large blueshift as a result of reduced dot height. In addition, the intensity of emission significantly increases as a result of improved crystalline quality induced by the thermal treatment. The effects of structural anisotropy of the quantum dashes are studied in terms of polarized emission. (C) 2010 The Japan Society of Applied Physics