Al Doping Influence on the Properties of Sol-Gel Synthetized ZnO Nanoparticles

Herein, zinc oxide (ZnO) nanocrystalline powders with different aluminum (Al) concentrations (from 0 to 4 wt%) have been successfully synthesized via sol-gel technique. The structure and morphology of the Al-doped ZnO (AZO) nanoparticles are investigated using X-ray powder diffraction (XRD) and scanning electron microscopy. The XRD results reveal the reduction in the crystallite size with increasing the Al doping ratio. ZnO phase is observed in all samples with no extra peaks. In addition, UV-vis diffuse reflectance spectroscopy is used to study the effect of Al dopant on the ZnO nanopowder optical properties. it is concluded that increasing Al concentration leads to decrease in energy gap (E-g) value from 3.30 eV (for undoped ZnO) to 3.25 eV (for AZO with highest concentration, 4 wt%). Finally, according to the obtained results, the ability to tune the bandgap of the prepared samples makes them superior candidates for using in various applications, especially optoelectronic devices.