Humidity Sensor Based on Nanostructured Ferric Oxide Thick Film

ABSTRACT The present paper reports the preparation of nanostructured ferric oxide film by screen printing method and their humidity sensing properties. Sensing material has been characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). XRD pattern revealed crystalline α-phase and rhombohedral crystal structure. SEM images show porous nature of sensing material throughout the surface. Nanocrystalline Fe2O3 thick film was prepared on borosilicate glass substrate by a screen printing method. The sensing film with silver contacts was put in the specially designed humidity chamber and the variations of resistance at different value of %RH of the sensing elements were measured. The average sensitivity was found 8.11 MΩ/%RH over the entire range of relative humidity. Results were found to be reproducible with 2% hysteresis.