Ayed Najim Salih and Usama Ibrahim Hassan 2023. Study the effect of the type and nature of the substrate on the optical properties of the thin films of (NiO) prepared by spin coating method. Tikrit Journal of Pure Science. 20, 1 (Feb. 2023), 126–131. DOI:https://doi.org/10.25130/tjps.v20i1.1145.