Preferential nucleation and growth of InAs/GaAs(0 0 1) quantum dots on defected sites by droplet epitaxy

A double-layer InAs/GaAs(0 0 1) quantum dot structure grown by droplet epitaxy was found to have V-shaped defects, with the two arms of each defect originating from a buried quantum dot and extended to the top surface. Quantum dots on the sample surface nucleated and grew preferentially on top of the arms of the V-shaped defects. The mechanism behind the observed phenomenon was discussed.