Influence of copper doping on structural, optical and sensing properties of spray deposited zinc oxide thin films

Nanostructured pure and copper doped zinc oxide thin films were deposited using spray pyrolysis technique and their structural, morphological, optical and ammonia vapour sensing properties were investigated. XRD and FESEM data confirmed the decrease in crystallite size with increase in Cu-dopant concentration. UV-vis spectra revealed the decrease in band gap and transmittance when Cu concentration increased. The Cu-doped films we report have much better performance than those reported so far with a faster response and recovery times of 30 and 14 s respectively towards sensing 50 ppm of NH3.