Formation of Spatially Addressed Ga(As)Sb Quantum Rings on GaAs(001) Substrates by Droplet Epitaxy

In this work we report on the ability to form low density Ga(As)Sb quantum ring-shaped nanostructures (Q-rings) on GaAs(001) substrates by the droplet epitaxy technique. The Q-rings are formed by crystallization of Ga droplets under antimony flux. After being capped by a GaAs layer, these nanostructures show surface mounding features that are correlated with the buried nanostructures, as demonstrated by TEM analysis, permitting an easy surface location of the optically active Q-rings.