ZnO–SiO2 core–shell nanorod composite: Microstructure, emission and photoconductivity properties

ZnO–SiO2 core–shell nanorod (NRs) composites have been synthesized using a chemical method by varying the number of SiO2 coating between one and ten, and their optical and photoconductivity properties have been investigated. Ultraviolet (UV) to visible emission peak intensity of the composites is increased as compared to pristine ZnO NRs, being maximum for the five times coated NRs due to the reduction of surface states. The same composite shows about an order of magnitude increase in the UV photosensitivity. The carrier relaxation during steady-state UV illumination decreases as the number of shell coating increases.