Optical and electrical characteristics of radio frequency sputtered ITO and In-free transparent conductors

In this work the optical and electrical characteristics of radio frequency sputtered indium tin oxide (ITO), aluminum doped zinc oxide (AZO) and nickel oxide (NiOx) are reported. ITO and AZO films showed very high visible transmittance values, with maxima up to 90-91%, and sheet resistance of 35 and 33 Ω/□, respectively, while non stoichiometric NiO films showed visible transmittance up to 53% and sheet resistance of several tens of KΩ/□. Properties of the films were correlated to their structure and morphology which are strongly dependent on the growth parameters.