Structural, dielectric, impedance, complex modulus, and optical study of Ni-doped Zn<sub>(1−x)</sub>Ni<sub>x</sub>O nanostructures at high temperatures
Fiaz Ahmad, Asghari Maqsood
Abstract
Abstract This experiment addressed the effect of Nickel-doped on the dielectric, ac conductivity, and optical properties of pure and doped Zn (1−x) Ni x O (x = 0, 3 and 6%) nanostructures. The un-doped and Ni-doped ZnO nanostructures were synthesized using co-precipitation. In this paper, the frequency-dependent dielectric and the electrical conductivity of un-doped and Ni-doped Zn (1−x) Ni x O nanostructures were examined at various temperatures ranging from 320 K to 460 K using an LCR meter. For the morphological and optical investigation, the prepared samples were analyzed using field emission-scanning electron microscopy (FE-SEM), and UV visible Spectroscopy was used at room temperature. The dielectric constant ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>ε</mml:mi> <mml:mo accent="false">′</mml:mo> </mml:math> ), dielectric loss ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>ε</mml:mi> </mml:mrow> <mml:mo accent="false">″</mml:mo> </mml:math> ), tangent loss (tan δ ), the real as well as the imaginary part of the impedance against the frequency ranging from 100 Hz to 2 × 10 6 Hz that declines with increases in frequency at different temperatures ranging from 320–460 K. However, the electrical conductivity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>a</mml:mi> <mml:mi>c</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) increased with the increase in frequency was examined. The ac conductivity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>σ</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>a</mml:mi> <mml:mi>c</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) follows Jonscher,s power law that the electrical conductivity is enhanced with increasing doping concentration. The optical transmission area also improved due to an increase in Ni-doping concentration in ZnO. The optical bandgap of pure and Ni-doped ZnO nanostructures is in the range lies 3.30–3.12 eV found that to decrease with the increase in Ni doping concentrations.