Influence of nickel thickness on the properties of ITO/Ni/ITO thin films

ITO single-layer and ITO/Ni/ITO (INI) multilayer films were deposited by reactive magnetron sputtering on unheated polycarbonate (PC) substrates. The influence of the Ni interlayer on the structural and optoelectrical properties of the film composite was investigated by keeping the thickness of ITO and INI films at 100 and 50/5/45 nm, respectively. Deposited ITO and INI films had an optical transmittance at a wavelength of 550 nm of 84% and 73% by discounting the PC substrate, respectively, while INI films exhibited a resistivity 10 times lower than that of ITO films (3.2 × 10 −4 Ω cm vs. 3.0 × 10 −3 Ω cm, respectively). XRD diffraction patterns demonstrated that the deposited ITO films had In 2O 3 diffraction peaks at (1 0 0) and (2 2 2). In contrast, INI films did not have any diffraction peaks. Surface morphology also appeared to influence the Ni interlayer. Specifically, INI films exhibited a lower root mean square (RMS) roughness of 0.5 nm compared with ITO films, which had RMS roughness of 2.1 nm. The figure of merit reached a maximum of 1.3 × 10 −3 Ω −1 for INI films which is greater than that of ITO films (0.5 × 10 −3 Ω −1).