Photoelectron Properties of Nanocrystalline TiO2 Films Prepared by a Powerful Hydrothermal Technique

In this article, nanocrystalline anatase TiO2 films were prepared using a powerful hydrothermal technique and characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopic (XPS), and UVvis absorption spectra. A metalsemiconductormetal ultraviolet (UV) detector based on TiO2 films with Au electrodes was fabricated. The photoelectron properties of the TiO2 films, including currentvoltage (IV) curves under UV illumination, spectral response and response time were studied in detail. The results of the experiment demonstrate that the crystallinity of the TiO2 film was greatly improved by the hydrothermal technique: the atom ratio between Ti and O on the surface of TiO2 film is calculated to be 1.87:1, which indicates that the obtained TiO2 film has less oxygen vacancies. The improved crystallinity as well as the correspondingly decreased hole trap concentrations finally resulted in a short photoresponse decay time of 4.183 s. Meanwhile, a responsivity of 56.5 mA/W, a low dark current of 5.95 nA, a UV photo-to-dark current ratio of 10(3) were also obtained for the TiO2-based detector, all of which suggest that the fabricated TiO2 films are very promising in UV detection applications.