Sol–gel processed Al2O3 thick film template as sensitive capacitive trace moisture sensor

Sol–gel processed Al2O3 thick film template has been tested for the first time to fabricate a trace moisture sensor. The device consists of a thick film nano porous γ-Al2O3 film, electrodes coated by silver palladium (AgPd) conductive past on both sides of the film forming a parallel plate capacitor. A high change in capacitance was observed with increasing ppmV moisture level from 0 to 100 ppmV. The results show that sol–gel processed monoliths are promising materials for capacitive type trace moisture sensor.