Enhanced UV emission in ZnO/ZnS core shell nanoparticles prepared by epitaxial growth in solution

Co-precipitation in highly alkaline environment resulted in well crystalline ZnO nanoparticles over which ZnS shell was grown in situ in solution at room temperature. Formation of epitaxial hexagonal ZnS over wurtzite ZnO core particles have been confirmed by x-ray diffraction and transmission electron microscopy studies. The core ZnO nanoparticles show prominent UV emission which enhances appreciably due to ZnS shell formation in ZnO/ZnS core/shell particles. Experimental evidence indicates the quenching of non radiative recombination pathways due to shell formation. The results suggest that synthesized epitaxial core/shell particles have charge confinement mainly in the core region with type I characteristics of band alignment and can be useful for device applications.