ZnO and Au/ZnO thin films: Room-temperature chemoresistive properties for gas sensing applications

Year: 2016

Authors: Gaiardo A., Fabbri B., Giberti A., Guidi V., Bellutti P., Malagu C., Valt M., Pepponi G., Gherardi S., Zonta G., Martucci A., Sturaro M., Landini N.

Autors Affiliation: Univ Ferrara, Dept Phys & Earth Sci, Via Saragat 1-C, I-44122 Ferrara, Italy; MIST ER Scrl, Via P Gobetti 101, I-40129 Bologna, Italy; CNR, INO, Largo Enrico Fermi 6, I-50124 Florence, Italy; Bruno Kessler Fdn, MNF, Via Sommar 18, I-38123 Trento, Italy; Univ Padua, Dept Ind Engn, Via Marzolo 9, I-35131 Padua, Italy.

Abstract: Zinc Oxide has been widely investigated for its photocatalytic properties, which enhance the bulk/surface charge transfer at room temperature. At the same time, the doping of semiconductor materials with metals allows the modification of their physical and chemical properties, and hence their performance as gas sensors. The aim of this work was to investigate the difference between thin-film sensors based on pure ZnO nanoparticles and on gold-cluster decorated ZnO in photo-activation mode. The nanopowders were synthesized through simple sol-gel methods and chemically, morphologically and structurally characterized. Thin films were deposited by spin coating onto alumina substrates. The sensing layers were tested with several gases in photo-activation mode, illuminated with radiation wavelengths of 525, 468, 400 and 385 nm. Gold-decorated ZnO thin film showed some interesting features, such as better chemoresistive properties than pure ZnO under photo-activation mode, when illuminated with a wavelength of 385 nm. A selective response of the sensing film to NO2 under green light irradiation was observed, in particular in dry air condition. Furthermore, the humidity effect on the sensing responses was investigated, highlighting a possible application of Au/ZnO for the detection of few ppm of SO2 with a high percentage of relative humidity. (C) 2016 Elsevier B.V. All rights reserved.

Journal/Review: SENSORS AND ACTUATORS B-CHEMICAL

Volume: 237      Pages from: 1085  to: 1094

More Information: Thanks to Daniela Palmeri of the Ferrara Centre of Microscopy. This work was supported by Programma Operativo FESR 2007-2013, Regione Emilia-Romagna-Attivita I.1.1.
KeyWords: Gas sensors; Room temperature; ZnO; Gold decorated ZnO; Thin films
DOI: 10.1016/j.snb.2016.07.134

Citations: 54
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