CuO-ZnO SEMICONDUCTOR GAS SENSOR FOR AMMONIA AT ROOM TEMPERATURE

Pure nanostructure thick films, prepared by screen printing technique, were almost insensitive to NH3 at room temperature. Pure nanostructure thick films were surface activated with CuO by dipping them into an aqueous solution (0.01M) of CuCl2 for different intervals of time and fired at 500 0 C for 12h. CuCl2 is known to be unstable above 200 0 C and transforms in to CuO upon firing above 200 0 C. The grains of CuO would disperse around the grain of ZnO base materials. The CuO activated ZnO films dipped for 5 min were observed to be sensitive and highly selective to 100ppm of NH3 sensor in the presence of NH3 and other gases were studied and discussed. The better performance could be attributed to an optimum number of surface misfits in terms of CuO on the ZnO films.