Microstructural and optical properties of ZnO/V2O5 composites

ZnO/V₂O₅ mixed and bilayer composites on glass substrate were deposited by magnetron sputtering at room temperature. Mixed composites were prepared by dual target magnetron sputtering from both ZnO and V₂O₅ targets whereas bilayer composites were obtained by deposition of V₂O₅ bottom layer capped by ZnO thin layer. Post annealing treatment in oxygen ambience at different temperatures was conducted. Variation in microstructural and optical properties with the annealing temperature was investigated by scanning electron microscope (SEM), X-ray diffractrometer (XRD) and photoluminescence (PL) at room temperature. The results indicated that heat treatment in oxygen ambience provided more reaction points between ZnO and V₂O₅ for mixed composite whereas bilayer composite had a limited interaction at the interface of ZnO and V2Os layers. Presence of zinc oxide vanadates (α-Zn₃(VO₄)₂) after heat treatment revealed the temperature sensitive interaction between ZnO and V₂O₅. Dramatically enhanced visible light emission was observed from the annealed samples which is attributed to the presence of α-Zn₃ (VO₄)₂. The enhancement in light emission from composite ZnO/V₂O₅ could act as the promising application for future optoelectronic devices.