Ordered GaAs quantum dots by droplet epitaxy

We report the fabrication of highly ordered arrays of GaAs/AlGaAs quantum dots (QDs) by droplet epitaxy using in-situ direct laser interference patterning (DLIP). Two-dimensional arrays of Ga droplets with a periodicity of ~ 300 nm are initially formed on nanoisland structured AlGaAs surfaces due to the localised surface diffusion under the influence of a thermal gradient imposed by the light pulse. After crystallisation under an arsenic flux, precisely ordered arrays of GaAs single dots are obtained. The size distribution and optical properties of the ordered GaAs QDs are shown to be optimised by careful choice of parameters for nucleation and droplet formation.