Nonlinear alternating current conduction study in manganese-doped zinc oxide nanocapsules and nanoplates

Abstract

In this report, the real part of ac conductance (Σ(T, f)) of pure ZnO nanoparticle, manganese-doped ZnO nanocapsules and nanoplates was estimated as a component of frequency (f) by shifting zero-frequency Ohmic conductance (Σ₀) with the tuning of the temperature (T) to understand the nonlinear AC conduction mechanism in semiconductor. The UV–VIS absorption spectrum showed a change in band gap from 3.67 eV for pure ZnO NPs to 3.31 eV for Mn-doped ZnO NPs with the change in excitonic peak from 372.5 nm for ZnO NPs to 375 nm for Mn-ZnO NPs. The HRTEM and SAED analysis along with XRD showed formation of nanocapsules and nanoplates with hexagonal wurtzite crystal phase. The doped semiconductor nanocrystals showed a ‘T’ dependent transition nature. Scaling speculations from theoretical models are used to dissect the effects of ac conduction and the nonlinearity exponent (x_f) of the onset frequency ${{f}_{\mathrm{c}}\sim\Sigma }_{0}^{{x}_{f}}$. The overall scaling formalism for the ac conductance Σ₀ was properly scaled with a universal curve as per the information for Σ(T,f) under different T. The metallic and semiconductor contribution in the dc conductivity of the doped nanosystems is highlighted. The normalized conductance (Σ/Σ₀) as a function of normalized frequency curves was depicted by a single power law for Mn-ZnO nanocapsules and nanoplates. The AC conduction process showed that x_f is a lot of phase delicate and can be utilized to describe the phase changes in these doped nanosystems originated due to change in Mn²⁺ doping concentration.