Characterization of low-temperature-grown ZnO nanoparticles: The effect of temperature on growth

Abstract

The growth temperature of semiconducting nanoparticles is well known to be an essential factor in determining their structure and quality of characteristics. To create high-quality ZnO nanostructures, it is critical to optimize the growth temperature. The sol-gel approach is used to render ZnO NPs at different growth temperatures in this report. The influence of growth temperature on the material properties of ZnO nanoparticles has been extensively investigated. The scanning electron microscopy (SEM) images show needle-like structures when synthesized at low temperatures (35 and 45 °C) that transformed into spherical particles as the temperature of the growing medium increased to 75 °C. X-ray diffraction (XRD) analysis displays an increase in crystallinity with annealing temperatures. The average crystallite sizes of ZnO nanoparticles rose with increasing growth temperature and varied from 28 to 34 nm. The XRD peaks positions shift slightly towards lower 2θ angles with the growth temperatures brought about by a change in lattice parameters. The Fourier transform infrared spectroscopy (FTIR) study revealed the presence of a Z–O bond at around 680 cm−1. The intensity of the defect level emission (DLE) band decreased, as the growth temperature exceeded 35 °C. The photoluminescence (PL) study further demonstrated that the prepared nanoparticles had a strong emission peak at 546 nm. PL measurements confirm that with increasing growth temperature, the excitonic peak intensity increases, indicating that the quality of ZnO nanoparticles improves. The estimated bandgap changed from 3.31 to 3.24 eV with the growth temperature.