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Humidity Effects on Porous Silica Thin Films

Published online by Cambridge University Press:  10 February 2011

J. R. Kokan  and
R. A. Gerhardt
J. R. Kokan
Affiliation:
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245
R. A. Gerhardt
Affiliation:
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245
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Abstract

Impedance Spectroscopy is being used to study the humidity sensitivity of porous silica thin films. The films are processed via a colloidal sol-gel method which leaves some remnant potassium and sodium. Previous work on bulk porous silica samples processed by the same method showed that the dielectric properties and ac conductivity were very sensitive to changes in humidity. The aim of this work was to determine if the same dependencies could be found in the thin films. The capacitance, dielectric loss, and ac conductivity of the films were measured in a controlled environment chamber from 20–80% RH for frequencies ranging from 10Hz–10MHz. In addition to characterizing films with varying amounts of residual alkali ions obtained through leaching, we have also measured films that were surface doped with controlled amounts of KCl, LiCl, or NaCl. Relative humidity dependencies in the films are not as dramatic as in the bulk samples. The reasons for this behavior are not yet clear, but may be associated with the porosity, thickness, and surface area of the films.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 411: Symposium T – Electricaly-Based Microstructural Characterization , 1995 , 419
Copyright
Copyright © Materials Research Society 1996

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References

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