Preparation of In/sub 2/O/sub 3/ thin films by sol-gel process for ozone sensing

Abstract

In/sub 2/O/sub 3/ thin films on sapphire substrates have been prepared from indium isopropoxide solutions by sol-gel process. Highly sensitive films have been obtained by using aged solutions and 500/spl deg/C annealing temperature. The electrical resistance increases greatly with increasing ozone concentration in the ppb range. The sol-gel-derived sensors have ozone sensitivity as large as 6 at 45 ppb, and working temperature below 200/spl deg/C.