Core/shell of p-cu<inf>x</inf>o/n-zno nanowire arrays for h<inf>2</inf>s gas sensor

Abstract

© 2018 Trans Tech Publications, Switzerland. The p-Cux O core/n-ZnO shell heterostructure nanowire (NW) arrays were fabricated by thermal decomposition. Based upon the core/shell nanowire-based all oxide p-n junctions. The samples were analyzed by XRD, SEM, EDS and TEM. X-ray diffraction (XRD) analysis showed that the p-Cux O core/n-ZnO shell NW consisted of phase of p-Cux O and wurtzite phase of n-ZnO. The morphology analysis showed average diameter and length of nanowires of ̴ 50 to 200 nm and ̴ 10 to 30 µm, respectively. The EDS spectrum confirmed the presence of required elements in the p-Cux O core /n-ZnO shell NWs. It was found that Zn, O and Cu are distributed over the wire areas according to a ratio of 1:2 by atomic% ratio of Cu:Zn to get good core/shell structure. The TEM characterizations showed that the n-ZnO shell nanoparticles were comprised of n-ZnO polycrystalline nanoparticles (NPs) on the surface of p-Cu2 O core NWs. The H2 S gas sensing properties of the p-Cux O/n-ZnO NWs were evaluated in air containing dilute H2 S gas at sensing temperatures (T) of 350°C. The response of 20.6 for p-Cux O/n-ZnO NW sensor to H2 S gas was enhanced compared to that of the n-ZnO NW. The enhanced response of p-Cux O/n-ZnO NW sensor is due to increasing surface area, the increased amount of chemisorbed oxygen species on NP surface and the increased conductivity.