Dependence of structural and optical properties on annealing time of ZnO nanoparticles



X-Ray Diffraction, Fourier Transform Infrared, Transmission Electron Microscope, Ultraviolet-Visible spectroscopy


ZnO nanoparticles were processed by the coprecipitation method using hexahydrate zinc chloride (ZnCl2.6H2O) as a starting chemical and then adding sodium hydroxide (NaOH) dropwise.  The annealing process for ZnO nanoparticles was carried out at a temperature of 400 Co at different intervals, varying from 0 to 8 hours.

The structural and optical characteristics of ZnO powders were synthesized by X-Ray Diffraction (XRD), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR), and Ultraviolet-Visible spectroscopy (UV-Vis).

The XRD patterns reveal that the fabricated samples have a crystal structure, and an improvement in crystallinity occurs by increasing the annealing time. TEM images exhibit the formation of a “hexagonal wurtzite” structure of “ZnO” nanoparticles that agglomerate slightly by increasing the annealing time. The “FTIR” Spectra in a range of 400 to 4000 cm-1 exhibit peaks that correspond to “Zn-O” stretching modes and a redshift occurs upon increasing the annealing time. From the “UV-VIS” absorption spectra, the optical band gap is found to decrease, and Urbach energy increases by increasing the annealing time.

Author Biography

M.E. Sayed, Modern Academy for Engineering and Technology


Specialization: Solid State Physics
Awarded by: Faculty of Women, Ain Shams University, 2020.


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