Field emission from the structure of well-aligned TiO2/Ti nanotube arrays

Abstract Well-aligned TiO 2 /Ti nanotube arrays were synthesized by anodic oxidation of titanium foil in 0.5 wt.% HF in various anodization voltages. The images of filed emission scanning electron microscopy indicate that the nanotubes structure parameters, such as diameter, wall thickness and density, can be controlled by adjusting the anodization voltage. The peaks at 25.3° and 48.0° of X-ray diffraction pattern illuminate that the TiO 2 nanotube arrays annealed at 500 °C are mainly in anatase phase. The filed emission (FE) properties of the samples were investigated. A turn-on electric field 7.8 V/µm, a field enhancement factors approximately 870 and a highest FE current density 3.4 mA/cm 2 were obtained. The emission current (2.3 mA/cm 2 at 18.8 V/µm) was quite stable within 480 min. The results show that the FE properties of TiO 2 /Ti have much relation to the structure parameters.