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A simple moisture sensor working at room temperature has been fabricated using porous silicon (PS) coated with porous γ-aluminium oxide ( γ-Al2O3). Porous silicon was formed by electrochemical anodization of p-type silicon. Thereafter, a porous layer of the PS was dip coated with γ-Al2O3 film. The γ-Al2O3 coating solution was made by a simple sol-gel method. The coated structure was sintered at 500°C for 30 m to form a nano porous layer of metal oxide on the porous silicon. Sintering the γ-Al2O3 -coated PS sample improves the stability of the sensor. Two different sensors with membrane-type metal contact have been fabricated by varying electrochemical parameters of PS. The sensors were tested to detect low moisture content in the N2 gaseous atmosphere in the range of 25 to 200 μl. Results show that suitable pore morphology of the hybrid structure will enable one to obtain characteristics of a sensor comparable to the commercial porous alumina moisture sensor. It was further observed that the sensor output is highly reproducible and has negligible hysteresis.