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Journal of Sensors
Volume 2009 (2009), Article ID 402527, 5 pages
http://dx.doi.org/10.1155/2009/402527
Research Article

Field-Assisted and Thermionic Contributions to Conductance in S n O 𝟐 Thick-Films

1Department of Physics, University of Ferrara, Via Saragat 1/C, 44100 Ferrara, Italy
2Institute of Materials Science and Technology (INTEMA), National University of Mar del Plata, CONICET, Juan B. Justo 4302, B7608FDQ Mar del Plata, Argentina

Received 27 January 2009; Revised 27 May 2009; Accepted 23 June 2009

Academic Editor: Giorgio Sberveglieri

Copyright © 2009 C. Malagù et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A deep analysis of conductance in nanostructured S n O 2 thick films has been performed. A model for field-assisted thermionic barrier crossing is being proposed to explain the film conductivity. The model has been applied to explain the behavior of resistance in vacuum of two sets of nanostructured thick-films with grains having two well-distinct characteristic radii ( 𝑅 = 2 5  nm and 𝑅 = 1 2 5  nm). In the first case the grain radius is shorter than the depletion region width, a limit at which overlapping of barriers takes place, and in the second case it is longer. The behavior of resistance in the presence of dry air has been explained through the mechanism of barrier modulation through gas chemisorption.