Nickel diffusion in CuInSe2 thin films was studied in the temperature range 430-520 degrees C. Thin films of copper indium diselenide (CuInSe2) were prepared by selenization of CuInSe2-Cu-In multilayered structure on glass substrate. A thin film of Nickel was deposited and annealed at different temperatures. Surface morphologies of the Ni diffused and undiffused CuInSe2 films were investigated using scanning electron microscope. The alteration of Nickel concentration in the CuInSe2 thin film was measured by Energy Dispersive X-Ray Fluorescence (EDXRF) technique. These measurements were fitted to a complementary error function solution and the diffusion coefficients at four different temperatures were evaluated. The diffusion coefficients of Ni in CulnSe2 films were estimated from concentration profiles at temperatures 430-520 degrees C as D = 1.86 x 10(-7)(cm(2) s(-1))exp[-0.68(eV)/kT]. (C) 2008 Elsevier B.V. All rights reserved.