Temperature-Dependent Exciton Dynamics in CdTe Quantum Dot Superlattices Fabricated via Layer-by-Layer Assembly

The formation of minibands in quantum dot (QD) superlattices (SLs) dramatically increases the mobility of carriers, giving a new way to apply QDs for optoelectronic devices. In previous studies on QDSLs, only a few studies have investigated the temperature dependence of the photoluminescence (PL) properties of QDSLs focusing on the formation of minibands. Here, a new model is proposed that simultaneously considers the extended and localized exciton states formed in the QDSLs to clarify the PL mechanism of QDSLs. By systematically investigating the temperature dependence of absorption, PL spectra, and PL decay profiles in CdTe QDSLs, it is found that the Stokes shift becomes smaller and the PL decay time of the miniband edge PL becomes longer with an increase in temperature. The elucidated PL mechanism of QDSLs will help clarify further photoexcited dynamics and their physical mechanism intrinsically appearing in the QDSLs with the miniband.