<p>Pure zinc oxide (ZnO) nanoparticles and ZnO-Bi₂O₃ nanocomposites are synthesized using a chemical co-precipitation method. X-ray diffraction analysis has revealed the structural properties of the nanocomposites. The chemical and elemental compositions are determined by Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. Scanning electron microscopy examines the microstructure and surface morphology. Current–voltage (I–V) characteristics are measured at temperatures ranging from 80 to 300&#xa0;K to evaluate&#xa0;the high- and low-temperature activation energies. Capacitance–voltage (C–V) characterization at room temperature and various frequencies have exhibited the significant frequency dispersion due to the presence of defects. The observed decrease in capacitance with increasing frequency indicates the dominant role of the interfacial phenomena at lower frequency values. Furthermore, the activation energies for both samples were obtained from the temperature dependence of the conductance at a constant frequency (100&#xa0;Hz) and compared with those derived from the temperature dependence of the saturation current. These two approaches have yielded consistent results for the activation energies and finally investigated the magnetic behavior of the prepared samples.</p> Graphical abstract <p></p>