Investigation on ozone-sensitive In2O3 thin films

Indium oxide (In2O3) thin films have been prepared by sol-gel and RF sputte ring techniques. The sol-gel film appeared to be much more sensitive to ozo ne compared to the RF sputtered film. The morphology of both films was exam ined by SEM, while their chemical composition was analyzed using X-ray phot oelectron spectroscopy (XPS) in order to understand the properties responsi ble for the high sensitivity of sol-gel films. The examination results show ed that the sol-gel films are very porous and uniform in grain size, but th e RF films are relatively dense and of coalescent grains. XPS analysis also highlighted that there may be oxygen vacancies on the surface of sol-gel f ilms. The large surface areas of sol-gel films and oxygen deficiency in the film structure are responsible for its higher sensitivity. (C) 1999 Elsevi er Science S.A. All rights reserved.