Facile synthesis of low band gap ZnO microstructures

In this work a simple chemical route was employed to synthesize ZnO microparticles by precipitation from aqueous solution of ZnCl₂ as precursor, NaOH as oxidizing and sodium dodecyl sulfate (SDS) as surfactant. Samples of ZnO microparticles were analyzed by scanning electron microscopy (SEM), FTIR spectroscopy, Raman spectroscopy, X-Ray diffraction, UV/Vis-NIR diffuse reflectance, high resolution transmission electron microscopy (HR-TEM), and N₂ adsorption-desorption. It was observed from SEM analysis that ZnO microparticles with morphologies resembling six-blade impeller with diameters in the range of 500 nm to 1 m, and sheet-like (approximately 200 nm × 300 nm) were obtained through this technique. X-Ray diffraction and Raman analyses confirmed the obtaining of hexagonal wurtzite ZnO crystal structure. The calculated band gap energy was 3.19eV, which is slightly lower than the average value reported in the literature. Specific BET area of ZnO microparticles was 26.5 m²/g.