Morphology and crystal quality of InAs QDs grown by MOVPE using different grqwth modes

Abstract

Morphology and crystal-quality of InAs/In0.53Ga 0.47As/InP quantum dots (QDs) grown by metal-organic vapor phase epitaxy (MOVPE) in N2 ambient using different growth modes have been studied. It is found that the morphology and crystal-quality of InAs QDs are dependant on the growth modes. After optimizing the dots' growth modes, dots' size dispersion and crystal-quality are both improved greatly, resulting in the enhancement factor of ∼ 2.9 in the photoluminescence (PL) peak-intensity from single QD. When the dots are buried, the dot size decrease compared with the free-standing dots due to the soon capping layer deposition during dots' being buried. The thermal activation energy measured is comparable to the valence-band offset in the QD system calculated by 8 kp theory model. This indicates the PL quenching induced by the interface defects is suppressed due to the defect density lowering in the QDs grown by such optimized growth mode.