Here, Mn-doped ZnS (Mnx Zn1-x S) nanorods were synthesized using solvothermal processes and were characterized by X-ray diffraction and scanning and transmission electron microscopy. Positron lifetime and Doppler broadening measurements were carried out on powdered samples with different dopant concentrations. A transformation from hexagonal to cubic structure was observed almost concomitantly with the filling of Zn2+ vacancies and/or substitution of Zn2+ ions by Mn2+ ions. The lifetime of positrons annihilating at the surfaces of nanorods decreased with increase in their diameter during increased doping by Mn2+ ions. At concentrations above 20%, pyramid-like coarse crystals of MnS were found to coexisted with the ZnS nanostructures. The interior of the nanorods seemed to be free of vacancy-type defects unlike in the case of ZnS nanoparticles.

Defect-Related Aspects of Mn-Doped ZnS Nanorods and Morphological Changes Revealed from Positron Annihilation Spectroscopy. P.M.G.Nambissan, S.Biswas, S.Kar, S.Chaudhuri: Physica Status Solidi C, 2007, 4[10], 3889-94