Selective formation of InAs quantum dot arrays by direct deposition of indium nano-dots using a nano-jet probe

We propose a new nano-probe-assisted technique which enables the formation of site-controlled InAs quantum dots (QDs). High-density two-dimensional indium (In) nano-dot arrays on a GaAs substrate were fabricated by using a specially designed atomic-force-microscope (AFM) probe (the nano-jet probe). This developed probe has a hollow pyramidal tip with a sub-micron size aperture on the apex and an In-reservoir tank within the stylus. By applying a voltage pulse between the pyramidal tip and the sample, In clusters were extracted from the reservoir tank within the stylus through the aperture, resulting in the In nano-dot formation. These In nano-dots were directly converted to InAs arrays by subsequent annealing with irradiation of arsenic flux.