Application of atomic-force-microscope direct patterning to selective positioning of InAs quantum dots on GaAs

The application of atomic-force-microscope (AFM) direct patterning to the selective positioning of InAs quantum dots (QDs) on a (100) GaAs substrate has been proposed and experimentally implemented. The AFM direct patterning was used to generate various patterns of several tens of nanometers in size, and InAs QDs were subsequently grown by a metalorganic chemical vapor deposition technique. A nonuniform distribution of the QDs was observed near the patterns. The detailed shape of the QD distribution and the size of the QDs depended on the geometrical properties such as the sidewall angle, the spacing, and the width of the patterns. We have been able to ascertain, through our work, what growth conditions are necessary for QDs’ alignment along the patterns.