Optical And Photocatalytic Properties Of Oblique Angle Deposited Tio_2 Nanorod Array

摘要

Using an oblique angle deposition technique, an array of well-aligned and tilted TiO_2 nanorods has been fabricated by electron-beam evaporation method. The as-deposited TiO_2 nanorod array is amorphous and porous with fibrous fine structures on the surface of individual nanorods. After annealing, the amorphous TiO_2 crystallizes gradually into an anatase phase with annealing temperature and duration, but no visible change occurs in the porous morphology and surface fine structures even when annealed at 500 ℃ for 5 h. The annealing under O_2 flow causes the optical band gap of TiO_2 to increase from 3.32 to 3.39 eV, due to the decrease in oxygen defect concentration. The photocatalytic activity of the annealed TiO_2 sample is doubled compared with that of the as-deposited sample. The enhanced specific surface area by the porosity and fine structures of obliquely deposited TiO_2 nanorod array is very promising for the applications such as chemical sensor, photovoltaic solar cell, and photocatalyst material for environmental protection.