Title: SnO2/ZnO double layer thin films: a novel economical preparation and investigation of sensitivity and stability of double layer gas sensors

Authors: M.R. Vaezi, A. Shokuhfar, S.K. Sadrnezhaad, T. Shokuhfar

Addresses: Advanced Materials Research Center, Materials and Energy Research Center, Karaj, Iran. ' Department of Materials Science and Engineering, Advanced Materials and Nanotechnology Research Center, K.N. Toosi University of Technology, Tehran, Iran. ' Department of Materials Science and Engineering, Center of Excellence for Production of Advanced Materials, Sharif University of Technology, Tehran, Iran. ' Department of Materials Science and Engineering, Advanced Materials and Nanotechnology Research Center, K.N. Toosi University of Technology, Tehran, Iran

Abstract: A double-layer SnO2/ZnO gas sensor was produced by utilisation of SnO2 and ZnO thin films. Top layer consisted of SnO2 produced by a sol–gel-controlled annealing technique. Bottom coating consisted of ZnO thin film precipitated by Two-Stage Chemical Deposition (TSCD) from an aqueous zinc-containing solution. Both top and bottom coatings were analysed by SEM, XRD, EDAX and AAS. Gas sensitivity of the SnO2/ZnO double layer was determined by electrical resistance measurements. Although sensitivity was slightly reduced by double-layer formation, selectivity and stability were considerably improved by combination of the two thin layers. The existence of an interfacial transition layer between SnO2 and ZnO and stabilisation mechanism of the SnO2/ZnO double layer were rigorously investigated in this research.

Keywords: double-layer thin films; gas sensors; sol gel; two-stage chemical deposition; nanomanufacturing; nanotechnology; tin oxide; zinc oxide.

DOI: 10.1504/IJNM.2008.017839

International Journal of Nanomanufacturing, 2008 Vol.2 No.1/2, pp.59 - 69

Published online: 19 Apr 2008 *

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