Development of commercial nanoporous trace moisture sensor following sol-gel thin film technique

A simple laboratory technique for the routine preparation of gamma-alumina (Al2O3) thin films on gold electrodes coated on an a-alumina substrate (10 mm x 20 rum x I mm) is described here. Prepared thin films and porous electrodes are dried at 100 degrees C and sintered at 400-550 degrees C for 4 h to achieve the gamma-Al2O3 phase. Further the temperature is shifted to 950 degrees C for 1.5 h for curing the electrodes. Microstructure of the films are analysed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM). The studies suggested that doubly coated gamma-Al2O3 led to an increase in the surface roughness of the deposited film which provided a unique sensor sensitive to trace moisture on a ppm level by volume (ppm(v)). (C) 2007 Elsevier B.V. All rights reserved