Stacked InAs self-assembled quantum dots on (001)GaAs grown by molecular beam epitaxy

We report stacked InAs self-assembled quantum dot (QD) structures separated by GaAs interval layers grown by molecular beam epitaxy on a (001) GaAs substrate. The InAs QDs were vertically aligned up to the 9th layer. Strain in the interval layer induced by the lower QD strongly influences the upper QD alignment. A large defect due to lateral In segregation was observed with multiple stacked InAs self-assembled QD structures, which suppresses further vertical alignment of QDs in the upper region and decreases photoluminescence intensity drastically Optical memory effect of InAs QDs buried in Schottky barrier diode was observed with memory retention time of 0.48 ms for the first time.