Tuning of structural, optical, dielectric and transport properties of Fe-doped ZnO:V system

Abstract Iron and vanadium co-doped ZnO nano-structures have been synthesized by solid state reaction method and the influence of Fe content on their structural, optical, dielectric and transport properties was investigated. The structural and optical characterizations of samples have been carried out by X-ray diffraction (XRD), transmission electron microscopy, Raman, UV–Visible and photoluminescence spectroscopy. Rietveld refinement of XRD data revealed that the lattice parameters and unit cell volume of the wurtzite ZnO decreased with Fe doping. The decrease in crystallite size and increase in micro-strain with doping have been observed from Williamson–Hall and size-strain analysis. The red shift in the band gap (from 3.29 to 3.24 eV) and increase in the dc activation energy (from 0.196 to 0.207 eV) with increase in Fe concentration are attributed to the enhancement of structural disorder/defects. The decrement in dielectric constant from 160 to 25 and ac conductivity from 16.6 × 10−6 to 1.4 × 10−6 at 10 kHz have been observed with Fe doping. The modulus and impedance studies revealed the presence of non-Debye relaxation, and contribution of grains and grain boundaries to the polarization. The study also revealed that the addition of Fe significantly modified structural, optical, dielectric and transport properties of the samples.