High room-temperature photoluminescence of one-dimensional Ta2O5 nanorod arrays.

In this study we analyzed the structural and electronic properties of a new morphological form, one-dimensional (1D) Ta2O5 nanorod arrays, which were synthesized by hot filament metal vapor deposition. Field-emission scanning electron microscopy (FESEM) showed the 1D Ta2O5 nanorods to be arranged in a large-area high-density array about 50 nm wide and approximately 550 nm long. X-ray photoemission spectroscopy (XPS) revealed not only the electronic structures and chemical properties of the 1D Ta2O5 nanorods but also their stoichiometric Ta and O compositions. Photoluminescence (PL) spectra showed intensive green-light, yellow-light and red-light emissions at room temperature. These emissions simultaneously emerged from the trap levels of oxygen vacancies within the Ta2O5 bandgap. The emission results strongly indicate that the 1D Ta2O5 nanorods are good room-temperature visible-light emitters.