Electronic properties of SnO2-based ceramics with double function of varistor and Humidity sensor

A. B. Glot, A.P. Sandoval-Garcia, A.V. Gaponov, R. Bulpett, B. J. Jones, G Jimenez-Santana

Research output: Contribution to journalArticle

Abstract

Tin dioxide based varistor ceramics SnO2-Co3O4-Nb2O5-Cr2O3-xCuO (x=0; 0.05; 0.1 and 0.5) were made and their electrical properties were studied. The highest nonlinearity coefficient and electric field (at current density 10-3 A cm-2) were obtained for 0.1 mol.% CuO addition. It was observed that low-field electrical conductivity is increased with relative humidity, therefore, materials obtained exhibit double function of varistor and humidity sensor. The highest humidity sensitivity coefficient is found for SnO2-Co3O4-Nb2O5-Cr2O3 ceramics (without CuO). Observed varistor and humidity-sensitive properties are explained in the frames of grain-boundary double Schottky barrier concept as a decrease of the barrier height with electric field or relative humidity. Using suggested simple theory and data obtained on isothermal capacitance relaxation, the energy of the grain-boundary monoenergetic trapping states were estimated. These values are less than found for activation energy of electrical conduction (as a measure of the barrier height). These observations confirm the barrier concept.
Original languageEnglish
Pages (from-to)21-32
Number of pages12
JournalAdvances in Technology of Materials and Materials Processing
Volume10
Publication statusPublished - 2009
Externally publishedYes

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