Growth and characterization of Fe-doped CuO/ZnO binary oxide thin films for possible optoelectronic applications

Nanoscale binary oxide thin film structures of pristine and Fe-substituted CuO/ZnO have been produced on soda-lime glass substrates by the SILAR method and characterized by different acceptable analytical approaches. The more irregular and lumpy ZnO in the pristine CuO/ZnO binary thin film sample evolved into more regular and hexagonal prismatic structures with the addition of Fe. XRD patterns of the samples indicated that both monoclinic CuO and hexagonal ZnO phases were present without any impurities. Optical analyses by meaning absorbance and transmittance measurements exhibit an important change in the energy band gap and transmittance value with the Fe doping ratio. The energy band edges of the bare sample shift to red with increasing Fe percentage in the starting solution, presumably due to an increase in the carrier concentration. The transfer length method (TLM) is used to define the conductivity properties of the samples, which considers the contact properties and structural features of thin films. The minimum specific contact resistivity of 0.865 × 106 Ω□ was obtained by 3.0 % Fe-implemented CuO/ZnO binary oxide samples, and the addition of Fe increased the effective transfer length of thin films.