Effects of precursors and caustic bases on structural and vibrational properties of ZnO nanostructures elaborated by hydrothermal method

The effects of zinc ions source (zinc acetate and zinc sulfate) and caustic bases (sodium and potassium hydroxides) on structural, morphological and vibrational properties of ZnO nanostructures elaborated by simple low temperature wet chemical process are studied. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (FTIR) and Raman spectroscopies. XRD results show that ZnO structures are polycrystalline hexagonal wurtzite with high crystal quality. SEM images reveal that the morphologies of the nanostructures are nanopencils except in those synthesized with zinc sulfate precursor and sodium hydroxide caustic base, where pencils agglomerate to form sand rose-like morphologies. EDAX measurements confirm the purity of the elaborated specimens by the presence of only Zn and O atoms in the samples. Raman spectroscopy studies show that the peaks, related to E-2 high mode, are more intense in ZnO structures elaborated with zinc acetate when NaOH is used, and in ZnO structures elaborated with zinc sulfate when KOH is employed.