A Zinc Oxide modified Porous Silicon humidity sensor

In this paper, a relative humidity sensor based on zinc oxide modified porous silicon was discussed. The porous silicon was prepared by electrochemical etching process first. Then the sol-gel precursor of Zinc Oxide was applied to the PS substrates and annealed at 450 degC. By this technique, it is possible to obtain a uniform zinc oxide film on the porous silicon substrates. The electrical conductivities of the porous silicon and zinc oxide/porous silicon structures under different humidity levels were measured. It is indicated that the modification of the porous silicon by sol-gel zinc oxide increase the sensitivity and shorten the response time to the relative humidity