EFFECT OF CU CONCENTRATION AND ANNEALING TEMPERATURE ON STRUCTURAL AND OPTICAL PROPERTIES OF FE/CU CO-DOPED ZNO NANOPARTICLES

Abstract

Fe/Cu co-doped ZnO nanoparticles were successfully synthesized via the sol–gel method and subsequently annealed at different temperatures (400 °C and 600 °C) to investigate the effect of Cu concentration and annealing on their structural and optical properties. The prepared samples were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, and scanning electron microscopy (SEM). XRD analysis confirmed the formation of a hexagonal wurtzite structure with no significant impurity phases, while variations in peak positions and intensities indicated successful incorporation of dopant ions and changes in crystallite size. An increase in annealing temperature resulted in improved crystallinity and increased crystallite size, whereas increasing Cu concentration led to a reduction in crystallite size and induced lattice distortion. FTIR spectra verified the presence of Zn–O bonding along with slight shifts due to doping effects. UV–visible analysis revealed a noticeable shift in the absorption edge and variation in the optical band gap, attributed to defect states and dopant-induced modifications in the electronic structure. SEM analysis showed agglomerated nanoparticles with morphology influenced by both annealing temperature and dopant concentration. The combined results demonstrate that tuning Cu concentration and annealing conditions significantly influences the structural and optical behavior of ZnO nanoparticles, making them suitable for potential applications in optoelectronic devices.