PREPARATION OF INDIUM OXIDE THIN-FILM BY SPIN-COATING METHOD AND ITS GAS-SENSING PROPERTIES

Thin films of In2O3 were fabricated on an alumina substrate by spin-co ating of an aqueous solution prepared from In(OH)(3), acetic acid and ammonium carboxymethyl cellulose, followed by drying at 110 degrees C and calcining at 600 degrees C. As observed by SEM, the films consiste d of a dense stack of tiny In2O3 particles (23-27 nm in diameter) and covered large grains of the alumina substrate well. Subsequently, film thickness was well controlled by the number of spincoatings. Gas sens ing properties were strongly dependent on the film thickness and tempe rature and fairly excellent sensing performances to H-2, CO and C3H8 w ere obtained with a 160 nm-thick film (5 times coated) at 350 degrees C. (C) 1998 Elsevier Science S.A. All rights reserved.