One-step electrodeposition of single-crystal ZnO nanotube arrays and their optical properties

ZnO nanotube arrays (ZNTAs) were successfully synthesized on FTO substrate using a one-step electrodeposition method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). It is shown that the single crystalline ZnO nanotubes with average diameter smaller than 200 nm grew along [0 0 1] direction. The growth mechanism of the ZNTAs was also discussed. Room temperature photoluminescence and UV-vis absorption spectroscopy were further carried out on ZNTAs to investigate their optical properties.