LPG gas sensing properties of CuO loaded ZnO thick film resistors

A gas sensing performance of pure and CuO-loaded ZnO thick films was studied by preparing thick films using the screen printing technique. The pure AR grade powder of the Copper Chloride was loaded at the various concentrations (1 At. wt. %, 3 At. wt. %, 5 At. wt. % and 7At.wt. %) into the pure AR grade powder of the Zinc oxide. The powders of different compositions were heated at 1000 °C for 12 hrs. The copper chloride transforms into copper oxide upon heating. These films of different compositions were fired at 550 °C for 30 min. The electrical, structural and morphological properties of the films were investigated. The X-ray diffraction analysis of pure and loaded films shows the polycrystalline nature. The surface morphology of the films was studied by SEM. The final composition of each film was determined by EDAX analysis. The gas response, selectivity, response and recovery time of the sensor were measured and presented. The sensing performance was tested for various gases at different operating temperatures. The ZnO sensor loaded with 5 At. wt. % of CuO is found to be high gas response to LPG gas than pure ZnO and other loading concentrations with fast response and recovery time.