Study on the optical and gas-sensing performance of Zn-doped CuO films

The pure copper oxide thin film was deposited on glass substrates by SILAR method with 30 cycles. To examine the doping effect, Zn-doped films at different doping ratios were prepared under the same conditions as the undoped film. The XRD, SEM and Raman measurements were performed to investigate the morphological structure. Analysis showed increasing aggregation and amorphous structure with doping. The optical parameters were characterized by spectrophotometer measurement and relevant formulas. The band gap energies were determined to increase from 2.50 to 2.79 eV with the increasing Zn rate. The Herve and Vandamme, Moss and Ravindra relations were used to determine the refractive index. The room temperature gas-sensing performance for the undoped and doped samples were reported and the responses for 5 ppm gas were calculated for the 5 ppm 249 %, 800 %, 189 % and 15 % for the CuO, 1Zn:CuO, 3Zn:CuO and 5Zn:CuO, respectively.