Sub micron scale patterning of material optical response through focused ion beam induced InAs/GaAs quantum dot nucleation

We report on the technique of using a focused ion beam to produce preferential sites for InAs/GaAs quantum dot nucleation. We mill an array of holes in the GaAs substrate and then deposit a thin layer of InAs below the critical thickness for dot formation in unpatterned areas. The array of holes on the substrate act as preferential nucleation sites and induce quantum dot formation only in the patterned regions. We conduct photoluminescence spectroscopy in a templated multilayer quantum dot sample at temperatures down to 10K and for various patterning conditions. We find that outside of our patterning regions we have no quantum dot luminescence, indicating that the patterning modifies the optical response of the material. We find that we can control this quantum dot formation down to array spacings of 250nm, showing excellent potential for this technique to be used for sub micron spatial control of a material's optical properties.