In this paper, we present the properties of CuI thin films at different concentration of iodine doping. Mister atomizer technique or so called spray pyrolysihas been applied to deposit CuI thin films on the glass substrate at a constant deposition parameter. The effects of iodine concentration to its surface morphology, electrical and optical properties were studied. The physical characteristics of sprayed CuI were determined by field emission scanning electron microscopy (FESEM), current voltage (I-V) measurement and UV-VIS-NIR spectrophotometer. A uniform thin films with nanoparticle sized of CuI was observed for all deposited samples. The resistivity shows a parabolic pattern where 3at% of iodine doping has the highest resistivity of 1.03 x 103 Ω cm. The transmittance for all samples was transparent of above 70% in the visible wavelength. The transmittance and absorption coefficient was measured and then the energy gap was determined which shows the direct transition of n=2. The maximum band gap observed here is 2.73 eV at 3 at% of doping concentration. The 3at% of iodine doping shows the highest resistivity, less transmittance and high band gap was due to the surface morphology and surface traps create by iodine doping.
