title: Enhanced Gas Sensing Properties of Spin-coated Na-doped ZnO Nanostructured Films.
abstract: In this report, the structures, morphologies, optical, electrical and gas sensing properties of ZnO and ZnO: Na spin-coated films are studied. X-ray diffraction (XRD) results reveal that the films are of a single phase wurtzite ZnO with a preferential orientation along (002) direction parallel to c-axis. Na doping reduces the crystalline quality of the films. The plane surface of ZnO film turned to be wrinkle net-work structure after doping. The reflectance and the optical band gap of the ZnO film decreased after Na doping. The wrinkle net-work nanostructured Na-doped film shows an unusually sensitivity, 81.9% @ 50 sccm, for CO2gas at room temperature compared to 1.0% for the pure ZnO film. The signals to noise ratio (SNR) and detection limit of Na-doped ZnO sensor are 0.24 and 0.42 sccm, respectively. These enhanced sensing properties are ascribed to high surface-to-volume ratio, hoping effect, and the increase of O- vacancies density according to Kroger VinK effect. The response time increased from 179 to 240 s by the incorporation of Na atoms @50 sccm. This response time increased as the CO2concentration increased. The recovery time is increased from 122 to 472 s by the incorporation of Na atoms @50 sccm.
authors.affiliation: Nanophotonics and Applications (NPA) Lab, Department of Physics, Faculty of Science, Beni- Suef University, Beni- Suef 62514, Egypt.|Space Research Lab, Solar and Space Research Department, National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Cairo, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Basyooni
authors.affiliation: Nanophotonics and Applications (NPA) Lab, Department of Physics, Faculty of Science, Beni- Suef University, Beni- Suef 62514, Egypt.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Shaban
authors.affiliation: Department of Physics, Faculty of Science, Fayoum University, Fayoum 63514, Egypt.
authors.forename: Adel M
authors.initials: AM
authors.lastname: El Sayed