Carrier transfer from wetting layer to quantum dots studied by cw-resolved and time-resolved photoluminescence in CdSe/ZnSe quantum dot system

Abstract

We have studied the cw-resolved and time-resolved photoluminescence (PL) spectra of the CdSe quantum dots (QDs), where PL peaks from the "wetting layer" and from the QDs are observed. The temporal behavior of the PL spectra after a short-pulse laser excitation provides evidence of carrier transfer from the wetting layer to the QDs for sufficiently low excitation power and sufficiently high temperature. The dependences of the cw-PL spectra and of PL lifetimes on excitation power are explained by the saturation of the carrier concentration in the QDs as the excitation power increases.