Interaction of self-assembled InAs/InGaAsP/InP (001) quantum dots

Inhomogeneous gain broadening in InAs/InP quantum dot (QD) lasers has been attributed to non-uniform QD size distribution. In this work, the interaction of two dots and three dots considering inter-dot distance, tilted position, QD size and surface ratio is investigated in terms of probability density function, eigenvalue, confinement potential of electrons and holes, strain distribution and piezoelectric potential for self-assembled InAs/InGaAsP/InP (001) quantum dots grown with double-capping procedure, by using the accurate two-step strain analysis model. It is found that strain distribution, piezoelectric potential and confinement potential are all changed, leading to optical transition energy changed and emission spectrum shifted. It is also discovered that there is greatly reduced probability density of the ground state electrons and holes in small QDs as well as large deviation in spatial overlap between electrons and holes of small QDs in the probability density distribution of the first excited state, when small QDs are overlapped with bigger QDs. Thus, the biggest InAs QD dominates the photoemission when it is closely surrounded by other QDs.