Bi-doped ZnO nanoparticles: enhanced structural and dielectric properties for device applications

Abstract

This document presents significant findings on the impact of Bi³⁺ substitution on the structural, dielectric, and electrical properties of \({{Bi}}_{x}{{Zn}}_{\left(1-\frac{3x}{2}\right)}{\rm{O}}\) nanoparticles with Bi ratios of x = 0.005 and 0.007, synthesized via the sol-gel technique. X-ray diffraction (XRD) analysis confirms a hexagonal wurtzite structure, demonstrating the successful incorporation of Bi atoms into the ZnO lattice. Refinement results indicate that both the lattice parameters and unit cell volume increase with higher Bi content. X-ray peak broadening analysis was performed using the Debye-Scherrer and Williamson-Hall (W-H) methods to evaluate the crystallite size and lattice strain. Impedance spectroscopy measurements were carried out over a frequency range of 40 Hz to 10⁷ Hz and a temperature range of 320 K to 410 K to assess the influence of frequency and temperature on the dielectric properties of the synthesized samples. Comparative Nyquist plots at a fixed temperature of 320 K revealed a decrease in impedance with increasing Bi doping concentration. This reduction in impedance is associated with an increase in electrical conductivity and a decrease in relaxation time, confirming that Bi doping enhances conductivity at 320 K. Furthermore, the improved electrical conductivity suggests that the material could facilitate electron transfer, making it a promising candidate for humidity and gas sensing applications. Additionally, dielectric characterization confirmed that the dielectric constant increases with higher Bi doping levels. The observed high permittivity values recommend the synthesized Bi₀.₀₀₇Zn₀.₉₈₉₅O compound for potential use in high-frequency devices. A more in-depth study of the structural, electrical, and dielectric properties demonstrates that Bi-doping effectively modulates the structural, electrical, and dielectric characteristics of ZnO nanostructures. This tuning of properties opens up new possibilities for future applications in energy storage systems, as well as in microwave and semiconductor technologies.

Graphical Abstract