Abstract

GONZALEZ-VIDAL, J.L. et al. CO sensitivity of undoped-ZnO, Cr-ZnO and Cu-ZnO thin films obtained by spray pyrolysis. Rev. mex. fis. [online]. 2006, vol.52, suppl.2, pp.6-10. ISSN 0035-001X.

In this work, we present the gas-sensing properties of chemically sprayed undoped (ZnO), copper-doped (Cu-ZnO), and chromium-doped ZnO thin films (Cr-ZnO), in an atmosphere of carbon monoxide, CO. Films were deposited at 400°C, using zinc acetylacetonate as zinc precursor. Three different atomic concentration ratios of the dopant were tested. A maximum sensitivity of the order of four orders of magnitude was obtained at measurement temperatures of 200 and 300°C in an atmosphere containing 100 ppm of CO. It was found that chromium doping favors a higher sensitivity at lower measurement temperatures (200°C), whereas the best sensitivity appears in copper-doped ZnO films at higher measurement temperatures (300° C). The thinnest films exhibited higher sensitivities.

Keywords : Zinc oxide; thin films; gas sensor; carbon monoxide.