Exciton response controlled by introducing a spacer layer in nitrided InAs quantum dots

We demonstrate the control of the exciton dynamics in self-assembled InAs quantum dots (QDs) by introducing a nitridation layer and a GaAs spacer layer on the QD surface. The PL intensity and decay time decrease owing to the introduction of the nitridation layer. Moreover, by inserting the GaAs spacer layer between the QD surface and the nitridation layer, the PL intensity of and decay time increase. These changes in PL characteristics correspond to that of the non-radiative recombination rate caused by crystal defects. Our results imply that the exciton response time of InAs QDs can be controlled by the thickness of the spacer layer. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)