Enhanced field emission from hydrogenated TiO2 nanotube arrays.

The field emission (FE) properties of TiO(2) nanotube arrays (TNAs) synthesized by anodization are dramatically improved after hydrogenation at various temperatures in a range of 400-550 °C. Compared with pristine TNAs, the turn-on fields of hydrogenated TNAs (H:TNAs) are significantly decreased from 18.23 to 1.75 V μm(-1), and closely related to hydrogenation temperature. Importantly, the optimized sample of H:TNAs prepared at 550 °C shows excellent FE performances involving both a low turn-on field of 1.75 V μm(-1), a high current density of 4.0 mA cm(-2) at 4.50V μm(-1), and a remarkable FE stability over 480 min. The substantially enhanced FE properties can be attributed to the combination of a typical tubular morphology, a reduced work function and the improved conductivity of H:TNAs.