Near infrared broadband emission of In_(0.35)Ga_(0.65)As quantum dots on high index GaAs surfaces

摘要

The morphology and optical properties of In_(0.35)Ga_(0.65)As/GaAs quantum dots (QDs) grown on (210), (311)A, (711)A, (731) and (100) substrates are investigated. QDs formed on (210) and (731) oriented substrates are grown by molecular beam epitaxy. Regular QDs are observed on (100), (311)A, and (711)A. Randomly distributed QDs and comet-shaped QDs form on (210) and (731) substrates, respectively. A high density of QDs on the order of 10~(11) cm~(-2) are obtained from (711) A. The optical measurement shows a spectrum linewidth (FWHM = 74.3 nm) of QDs on GaAs (210) three times wider than GaAs (100) substrate. Long exciton decay times, over 1 ns, are also measured by time-resolved photo-luminescence technique for all samples. Our results demonstrate the potential for QDs on GaAs high index substrates for wideband applications.