Studies on gas sensing performance of pure and surface modified ZrO2 thick film resistor

In this work, thick films of pure ZrO₂ powder were prepared by screen printing technique. The material was characterized by XRD, SEM, EDAX and UV spectroscopy Techniques. X-Ray Diffraction studies confirmed that the combinations of tetragonal and monoclinic structure. The gas sensing performances of various gases were tested. The thick films showed highest response to NH₃ (100 ppm) at 300°C. The film was modified by dipping in 0.1M CdCl₂ solution for the time intervals of 5, 10, 20 and 30 minutes and surface morphology was observed by SEM technique. The sensitivity and selectivity to different gases was tested and first time it was investigated that the film showed highest response to H₂S gas at operating temperature 300°C by dipping technique. The sensitivity and selectivity may be further enhanced by Cd doping. The quick response and fast recovery time was recorded.