Properties of nanocrystalline ZnS:Mn

In this paper, the effect of the Mn incorporation and its concentration variation over its whole solid solution range in nanocrystalline ZnS (0% to about 40%) has been studied. Such materials having a significant Mn content are also called diluted magnetic semiconductors (DMS). Till date, they have been studied only in the bulk or thin film form. Here the uniqueness of such a DMS in nanocrystallite form is presented. The samples were prepared by a chemical capping method. Zinc acetate, manganese acetate and sodium sulfide were used as reactants. Poly vinyl pyroledone was used as a capping agent for controlling particle size. The samples were observed to have cubic structure over the Mn concentration range studied. Unlike bulk samples, there was no crystalline phase change with Mn concentration variation. The material had a direct band gap of about 5.6 eV. It did not show any systematic change with Mn concentration. Photoluminescence intensity in ZnS:Mn showed significant enhancement upon Mn incorporation. There were two extra PL peaks after Mn incorporation in the nanocrystalline ZnS:Mn. PL also suggested Mn incorporation only up to about 40%. Lastly, the observed magnetic and electrical properties of nanocrystalline ZnS:Mn samples are stated. (C) 2004 Elsevier B.V. All rights reserved.