Comparative study of morphological, optical and conductive properties between low and heavily zinc doped nickel oxide thin films as hole transporting material

Abstract

Heavily Zinc ion (Zn2+)-doped nickel oxide (NiO) thin films had been prepared for the study of structural, optical and electrical properties in comparison with lower dopant concentration. Thin films were prepared through deposition on ITO coated glass substrate by using sol-gel spin coating technique. X-ray diffraction (XRD) patterns revealed the fact that Zn doped NiO (Zn:NiO) thin films are cubic in nature with two major diffraction peaks along (200) and (111) planes of cubic NiO phase. X-ray photoelectron Spectroscopy (XPS) data supported successful substitution of Zn2+ in NiO lattice. In, UV-Visible absorbance spectra the intensity maxima of the peaks was decreased with increase in doping concentration of Zn from 0% to 0.5–4.0%. The change in surface roughness of the Zn:NiO with varying dopant Zn2+ concentration was studied by Atomic Force Microscopy (AFM). Porus surface morphologies of the materials were evaluated in Field Emission Scanning Electron Microscopy (FESEM). The resistance change in both pure and Zn:NiO thin films was monitored by Electrochemical Impedance Spectroscopy (EIS) analysis.