M. H. Yousefi - Nanotechnology Research Group, Faculty of Applied Sciences, Malek-Ashtar University of Technology
A. A. Khosravi - Department of Physics, Faculty of Sciences, University of Shahed, Tehran, Iran
Kh. Rahimi
A Nazesh

Semiconducting nanoparticles now widely known as quantum dots have been the subject of intensive investigation during last two decades [1-2]. A variety of methods [3-4] have been deployed in orders to synthesize and control the size of nanoparticles. Independent of method of synthesis, one common thing about all ultra fine particles is that they exhibit physicochemical properties which are size dependent. The bulk material bandgap which is characteristics of a semiconductor material becomes a size dependent property. These particles then show a quantum confinement effect due to localization of charge carriers here after called quantum dots or quantum particles [4]. Free standing nanoparticles are therefore preferred in order to understand basic quantum size effects in these materials.In this work first we focus on the synthesis of ZnS and CdS quantum dots pure as well as doped with transition metal Mn. The characterization techniques employed to characterize the materials are UV-Vis, PL, XRD and TEM. Optical absorption spectra clearly reveal quantum size effect in both ZnS:Mn and CdS:Mn quantum dots