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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