Photoluminescence and plasma reflection spectra of colloidal quantum dots CdSe, PbS, GaAs

A simple technique for depositing colloidal quantum dots (QD) in relatively thick (up to 1 $\mu$m) layers on a glass substrate was tested. According to 3D-AFM topograms, it is concluded that QD is aggregated into conglomerates, which consist of densely-packed smaller particles that have the form of faceted plates. The experimental characteristics of the photoluminescence spectra are in good agreement with the theoretical ones. When the QD is transferred from the suspension to the substrate, a decrease in the quantum yield is observed. A resonance reflection was detected on the QD-PbS in the spectral region 8 $\mu$m and QD-CdSe/CdS 2 $\mu$m