Synthesis and optical characterization of aluminum doped ZnO nanoparticles

This paper reports on the structural and optical properties of Al doped ZnO nanoparticles prepared through a sol–gel method. Different atomic ratio's of Al were doped into ZnO ranging from 1 at% to 6 at%. X-ray diffraction (XRD) and FE-SEM results showed that the average crystallite size of ZnO nanoparticles decreased with increasing Al concentration. A compressive strain induced in ZnO with Al doping was calculated using W–H plot analysis. The band gap increased monotonously as Al concentration was increased from 1 at% to 6 at%. ZnO nanocrystals showed an emission peak positioned at 396 nm. The intensity of this peak decreases with Al doping for all concentrations. The decrease of the intensity of 396 nm emission peak is due to the worsening of the crystal quality due to Al doping. In addition to this, another peak at 437 nm is developed with Al doping and it is speculated to be due to the zinc interstitial defects.