The Ni-doped CdSe nanostructured thin films during the deposition procedure that govern the altering of the optical transitions have been investigated. The concentration of Ni as doping inside CdSe from 0.01, 0.02 to 0.03mol in the form of nanostructured thin layers have been fabricated through a simple chemical solution deposition approach. Doping of the Ni to CdSe adds the new transitions related to NiSe, which means the tiny concentration of Ni ions creates the new transition to CdSe that sample has multiple optical bandgaps. There is an order in band gap changing with doping concentration raising so that increasing the Ni2+ ions decreases the optical band gap to 1.59eV although the optical band gap for CdSe in bulk state is 1.74eV, so doping procedure decreases optical bandgap of CdSe that is mean doping procedure creates the new structure. It has shown that it’s possible to determine the Urbach energy of the samples from the absorption spectrum without the need to determine the adsorption coefficient from the determination of thickness. Degradation efficiency for pure CdSe is 86% while a sample of Ni-doped CdSe enhanced degradation efficiency until 93%.
