Structural, morphological, and gas sensing properties of Co-doped ZnO nanoparticles

Undoped and Co-doped ZnO nanoparticles (NPs) are prepared by a co-precipitation method. X-ray diffraction analysis confirms the undoped and Co-doped ZnO nanoparticles exhibited a hexagonal (wurtzite) crystal structure. Lattice parameters decreased slightly with Co concentration. The average crystallite size and microstrain were investigated by Williamson- Hall (W-H) analysis. The FESEM studies revealed the growth of nanoparticles with grain size about 42-65 nm. UV-visible absorption studies show the red shift in Co-doped ZnO samples. The sensor response was estimated by the change in the electrical resistance of the sample in the presence and absence of ammonia gas with fixed concentration of 10 ppm at 50 degrees C. The sensor response is found to be increased with the increase in doping concentration of Co. The sensor response in relation to Co concentration has been systematically studied. Co-doped ZnO sensor is well thought out as a novel gas sensor with large sensing characteristics; at the same time, the operating temperature of the sensor of 50 degrees C is significantly attractive to a greater extent owing to their long-term stability and less power utilization.