The zinc oxide (ZnO) - copper oxide (CuO) n-p junctions are a promising material for detecting ammonia gas. In this work, nanocomposite of ZnO: CuO thin films were deposited by using sol-gel spin coating method on a glass substrate.The search aimed to study the effect of annealing at 500oC on the physical properties and the effect of annealing on the sensing properties of the prepared films. The characterization of thin films before and after annealing treatment was studied by X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM) for the morphology of the surface and grain size of particles also, UV-Visible analysis for optical properties. Sensing properties were also studied before and after annealing. The results showed the films were polycrystalline in nature with a monoclinic phase and the crystalline size was 5.4 nm and 9.9 nm before and after annealing. The results of SEM and AFM showed the surface uniformly and particle size was 25nm to 32 nm before and after annealing. The results of sensing properties for ammonia gas showed the sensitivity was enhancement after annealing treatment.

Composite Films, Sol-gel Method, Optical Properties, Response and Sensitivity %, Sensing Properties.