Tailoring magnetic and photoluminescence properties in ZnS/ZnO core/shell nanostructures through Cr doping

Work on doped inverted core/shell semiconductor structure and study of their magnetic and luminescence properties is very rare. We have successfully prepared core/shell (C/S) nanostructure of important semiconductors ZnS core/ZnO shell with doping of chromium in both core and shell regions for tailoring magnetic and luminescence properties. Cooperative exchange of pinned spins at the interface of core and shell magnetic regions lead to ferromagnetism in ZnS:Cr/ZnO:Cr C/S nanoparticles (NP) at room temperature. Ferromagnetic interaction enhances at low temperature. Growth of hexagonal ZnO shell on cubic ZnS NPs in coprepitous aqueous solution has been confirmed by XRD and HRTEM analysis. Substitutional transition metal Cr in ZnS core and/or ZnO shell region could induce magnetic moments, create spin ordering and pinning while on C/S interface and also domain alignment leading to different magnetic states in varied C/S architecture. Cr also induces blue photoluminescence in doped ZnS/ZnO C/S NPs thus paving a possibility of tailoring multifunctional properties in C/S semiconductors architecture.