The effect of electron occupation on the photoluminescence from the self-organised InGaAs/GaAs quantum dots

The effect of electron occupation on the photoluminescence (PL) from quantu m dots (QDs) at low temperature is investigated in this work. The results o f PL measurements from self-organised InGaAs/GaAs QDs embedded in a field-e ffect structure are presented. It was found that the QD PL could be quenche d in reverse biased structure. This was related to a dissociation of photo- generated electron-hole pairs in high electric field. Filling of QDs with e lectrons results in the PL recovery. Further increase of QD electron occupa tion results in the PL peak redshift (6 meV) and in PL lineshape change. Th e PL peak intensity decreases and an additional feature on the high energy tail of the main PL peak can be observed. We relate the observed effects to a charge-induced energy shift of the PL resulting from an exchange interac tion between electrons and a hole in the QD and to the emission from excite d electronic state.