Tunable narrow emission in ZnS/CdS/ZnS quantum well structures prepared by aqueous route

Abstract ZnS/CdS/ZnS quantum wells (QWs) with tunable narrow emission due to narrow size distribution were successfully synthesized by wet chemical method. QWs give high luminescence and hence important materials for recent nanotechnology applications such as optoelectronics and bioimaging. In this work we put forward a QW structure with extended potential barrier, where electron and holes are confining in the core of ZnS and ZnS/CdS QDs by creating a ZnS/CdS/ZnS potential well like structure. Multilayers break the continuity of structure, which gives the combined advantages of ZnS, CdS and ZnS/CdS. This well like structure of quantum dots gives highest possibility to confine the electron and holes inside core and enhance the optical properties with suitable shell thickness. Structural, morphological and optical properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–visible absorption (UV–vis) and photoluminescence (PL) spectroscopy. Quantum yield of these quantum dot structures was also measured.