Variations in structural, optical, and dielectric properties of CuO nanostructures with thermal decomposition

Herein, we report the characterization of CuO nanostructures annealed at different temperatures, synthesized by chemical co-precipitation method. It is found in the XRD patterns that the peaks were broader at low temperatures due to increased defect density and poor crystallization suggesting that increasing annealing temperature enhances the degree of crystallization of the samples. Scanning electron microscopy (SEM) suggests that the CuO nanostructures change with increasing annealing temperature from rods to disc-shaped particles. It is observed in PL that with the increase in annealing temperature, the emission intensities increase for the same morphology due to the increase in oxygen vacancies (O.Vs) and improvement of crystallization. The dielectric constant has been increased with increasing temperature for the same morphology and is maximum for the sample annealed at 600 °C which is mainly due to the RDP and SCP. The relaxation peaks are shifted to the higher frequencies due to defect dipoles. Enhancement in conductivity is due to the growth of conducting grains. Our findings may provide comprehensive insight in designing high-performance electronic devices.