Effect of surface states on carrier dynamics in InGaAsP/InP stressor quantum dots

The carrier dynamics in strain-induced InGaAsP/InP quantum dots (QDs) is investigated by time-resolved photoluminescence and continuous-wave photoluminescence. The stressor QDs are fabricated by depositing self-assembled InAs islands (or stressor islands) on top of a near-surface InGaAsP/InP quantum well (QW). The temporal behaviour of the QD photoluminescence transients are observed to exhibit a two-phase decay. Rate equation analyses reveal that by increasing the distance of the QW from the surface the surface capture time constant is increased considerably while the capture time constant of an electron from the QW to the QD is decreased.