Enhanced sensing performance and mechanism of CuO nanoparticle-loaded ZnO nanowires: Comparison with ZnO-CuO core-shell nanowires

The synergism of nanocomposite heavily impacts the performance of gas sensing materials, that need to be systematically and deeply investigated to meet the high application requirement. In this work, we present gas sensors developed by ZnO-CuO core-shell nanowires (C-S NWs) and ZnO/CuO NWs (ZnO NWs modified by CuO nanoparticles) synthesized by a facile three-step process. The sensing performances for both structures were investigated toward the oxidizing gas NO2 and the reducing gas benzene. Results show that compared with pure ZnO NWs, ZnO/CuO NWs exhibits enhanced sensing performance and a n-type response behavior, while ZnO-CuO C-S NWs shows reduced sensing property and a p-type response behavior. The phenomenon is closely associated with the charge transfer at the p-n junctions contributing to adsorb the target gases for materials. Our study indicates that the construction method and their synergism are key factors to the effective design of gas sensors with MOS sensing materials.