Detection of optical emissions from deep localized states in a self-assembled InAs/GaAs QD structure

This work reports on the optical properties of self-assembled InAs/GaAs quantum dots (QDs) grown by molecular beam epitaxy. A sigmoidal temperature-dependent variation bandgap energy is detected from photoluminescence (PL) investigations studied sample. dependence was accompanied an anomalous increase in integrated PL intensity (IPLI) over temperature range 10 K to 110 K. Such observations are related existence deep localized states (LS) within QD structure. To illustrate presence LS, pump power-dependent measurements at different temperatures were performed. It found that peak (PLPE) gradually converts into a monotonous with gradual excitation density. These show saturation behavior limited number QDs. results provide clear evidence for levels InAs dots.