Galvanic deposition of ZnO nanorods and thermal annealing effects on their optical properties

► Driving force for galvanic deposition of ZnO is related to NaCl concentration. ► Increase of NaCl concentration promotes blue shift of UV emission of ZnO. ► Air thermal annealing at 300° improves ZnO quality and increases their UV emission. ► Air thermal annealing at above 400° decreases UV emission and enhances visible emission. ► Visible emission is related to surface defect induced by thermal annealing.