Synthesis, structure, and improved frequency-dependent transport properties of copper doped zinc oxide nanoparticles at high temperatures

Abstract

The nanostructures of ZnO are studied in this research utilizing a simple, eco-friendly, and cost-effective co-precipitation have a formula Zn 1 − x Cu ( x ) O with (x = 0.0, 0.03, 0.06, and 0.10). The effects of copper (Cu) doping on structure, morphology, impedance, dielectric, and electrical conductivity were investigated using an XRD, SEM, and LCR meter, respectively. All prepared samples have a hexagonal wurtzite structure, and the average crystalline size varies between 46 and 56 nm, according to the XRD spectra. Impedance measured data analyzes that a capacitance phase element perfectly modulates the fabricated samples with the equivalent circuits. Depending on the temperature, the examination of complex impedance and complex electrical modulus revealed a non-Debye types relaxation process. The Arrhenius plots for the conduction mechanism were used to investigate single activation energy. A correlated barrier hopping (CBH) model dominated the conduction process in un-doped and Cu-doped ZnO nanoparticles. The dielectric measurements in low-frequency at high temperatures regions exhibited high dielectric constant values for the prepared samples. Compared to undoped ZnO, the dielectric constant values increase with Cu concentration, also improving the ac conductivity of all Cu-doped ZnO nanoparticles, making them a suitable choice for energy storage applications. The electrical modulus displays a dual nature of relaxation times for all synthesized samples with lower values. • Pure ZnO and Cu-doped ZnO nanostructures have been fabricated using a Co-precipitation method. • The average crystalline size of ZnO and Cu-doped ZnO nanostructures lies at 46 nm to 56 nm. • The samples of pure and Cu-doped ZnO nanostructures showed negative temperature coefficient resistance (NTCR). • Dielectric and ac conductivity properties improved with the addition of Cu concentrations. • The Cu-doped ZnO nanostructures shall be beneficial for optoelectronics applications.