Raman Spectroscopy of ZnO Nanowires Obtained by Electrochemical Anodization: Effect of Thermal Treatment, Voltage and Anodizing Time

ZnO nanostructures obtained by electrochemical anodization of Zinc foil under voltage between 2.5 and 15 V, anodization time 1-5 min and thermal treatment at different temperatures (100-400 °C) were studied by Raman spectroscopy and electronic scanning microscopy. By scanning electron microscopy, it was found that at low values (time and voltage) nanoflowers with lengths close to 2 µm and diameters less than 100 nm are obtained, while at high values nanowires with lengths greater than 3 µm and diameters greater than 200 nm are observed. By Raman spectroscopy it was observed that the intensity of the E2H mode increases as increase both the anodization time and voltage. In addition, better crystal quality was observed in samples annealed at 300 °C.