Abstract
Ni doping in CuO showed successful replacement of Cu+2 ions by Ni+2 ions. Evidence of strain being developed due to doping was seen. Change in crystallite size was observed depending upon the role of Ni as a nucleating center. Intensity variations in absorption and emission spectra were observed which were related to the amount of defects or formation of new phases in the materials. A wide absorption window was observed due to exciton. A change in band gap was observed corresponding to the change in particle size. Zn doping in CuO caused a variation in crystallite size and incorporated defects which had effect on the optical properties. A change in band gap due to defect generated energy levels as well as quantum size effect was seen.