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

摘要

A simple laboratory technique for the routine preparation of γ-alumina (Al_2O_3) thin films on gold electrodes coated on an α-alumina substrate (10mm × 20mm × 1 mm) is described here. Prepared thin films and porous electrodes are dried at 100℃ and sintered at 400-550℃ for 4h to achieve the γ-Al_2O_3 phase. Further the temperature is shifted to 950 ℃ 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 γ-Al_2O_3 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).