ZnO:H thin films for room temperature selective NH3 sensors

Abstract

International audienceZnO thin films were deposited by magnetron sputtering in Ar and Ar+H2 atmospheres. The influence of the substrate temperature, Ts, on their optical, structural and electrical properties was investigated. The optical band gap, Eopt, of the films, from transmission and reflection spectra, ranged from 3.27 to 3.31 eV, and decreased with increasing Ts. The Urbach band tail width was also calculated - its value decreased with increasing substrate temperature. XRD analyses showed an improvement of the structural properties with increasing Ts. A discussion of the influence of Ts and hydrogen on the properties is presented. The change of the sensitivity in the presence of NH3 vapour at room temperature is also presented