Complex impedance, dielectric constant, electric modulus, and conductivity analysis of Cd doped ZnO nanostructures at high temperatures

Cd-doped zinc oxide (ZnO) nanostructures with a standard formulation Zn(1-x)Cd O-x (x = 0%, 3%, 6%, and 10%) were fabricated by a co-precipitation technique. The structural and morphological analyses were studied using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The Study of x-ray diffraction investigation indorses the existence of a wurtzite structure with a P6(3)mc space group in all the samples. Impedance spectroscopy, dielectric measurements, and electrical conductivity at different temperatures of 300-460 K with a frequency range from 20 Hz to 2 MHz were performed using an impedance LCR meter. The complex impedance spectrum (Z '' vs Z ') for all samples were fitted with a parallel bulk resistance (R-b) and capacitance (C-b) combination circuit. The results of the dielectric measurements indicate that the parameters epsilon ', epsilon '', and tan delta are reduced with the increasing frequency and increase with temperature. The complex electric modulus plots (M ', M '') with frequency have explained the non-Debye type of relaxations mechanism due to interfacial and depolarization. The variation of ac (sigma(ac)) conductivity with Cd concentration indicates a gradual increase because the impedance values with Cd-doped decrease. It is confirmed that the activation energies decrease with the doping of Cd concentration. Moreover, ac conductivity was then investigated by Jonscher's power law. Finally, the temperature-dependent exponent s fitted well with the correlated barrier hopping (CHB) conduction.