Effect of doping concentration of Cu2+ ion on ZnO thin film for detection of CO gas

In the present work, CO gas sensor based on ZnO (non-annealed) and ZnO:Cu (post-annealed) were prepared using chemical bath deposition technique using Zinc Nitrate Hexahydrate (AR), triethanolamine (AR), and sodium hydroxide (AR) as the source materials and Copper Nitrate Hexahydrate as source of the dopant and the prepared films were deposited on to the glass substrate. The prepared films were characterized by XRD (X-ray diffraction), SEM (Scanning Electron Microscope), EDAX, and UV–visible spectroscopy. The crystallite size was found to decrease on doping Cu. The formation of ZnO nanorods and nanospheroidals of ZnO:Cu was observed. The compositional analysis was done by EDAX. The band gap energy of the prepared film was found to vary from 3.9 eV to 3.6 eV. The electrical and CO gas sensing properties of thin films were also investigated. The response and recovery time of chemically synthesized ZnO thin films to CO gas were observed. A prototype based on the prepared sample is designed with the help of the Arduino UNO.