Investigation of interface defects in nanocrystalline SnO2 by positron annihilation

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)189-193
Journal / PublicationJournal of Physics and Chemistry of Solids
Issue number2
Publication statusPublished - 1999


The variations of grain size of nanocrystalline SnO2, prepared by the sol-gel route, during isothermal sintering are measured as a function of temperature. In the low temperature regime up to 500°C, grain growth is much faster. Isothermal grain growth kinetics are analyzed by measuring the grain size as a function of time in the low and high temperature regimes. The grain growth exponents (n) are approximately 3 and 2 for low and high temperature regimes, corresponding to surface diffusion and normal grain growth mechanisms, respectively. Results of positron annihilation spectroscopy indicate that there are two kinds of defects or free volumes in the interfaces: monovacancies and microvoids. In the low temperature regime, redistribution of free volume sizes occurs by coalescence of free volumes, while shrinkage of free volumes dominates during fast grain growth in the high temperature regime. Microvoids existed in the interfaces and exerted drag on the grain boundary during grain growth in the low temperature regime. © 1998 Elsevier Science Ltd. All rights reserved.

Research Area(s)

  • A. Ceramics, A. Nanostructures, C. Positron annihilation spectroscopy, D. Defects