title: Enhancement of the field emission from the TiO₂ nanotube arrays by reducing in a NaBH₄ solution.
abstract: A mass of oxygen vacancies are successfully introduced into TiO2 nanotube arrays using low-cost NaBH4 as a reductant in a liquid-phase environment. By controlling and adjusting the reduction time over the range of 0-24 h, the doping concentration of the oxygen vacancy is controllable and eventually reaches saturation. Meanwhile, the thermal stability of oxygen vacancies is also investigated, indicating that part of the oxygen vacancies remain stable up to 250 °C. In addition, this liquid-phase reduction strategy significantly lowers the requirements of instruments and cost. More interesting, reduced TiO2 nanotube arrays show drastically enhanced field emission performances including substantially decreased turn-on field from 25.01 to 2.65 V/μm, a high current density of 3.5 mA/cm(2) at 7.2 V/μm, and an excellent field emission stability and repeatability. These results are attributed to the oxygen vacancies obtained by reducing in NaBH4 solution, resulting in a reduced effective work function and an increased conductivity.
authors.affiliation: Key Laboratory of Atomic and Molecular Physics & Functional Materials of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University , Lanzhou 730070, China.
authors.forename: Xuqiang
authors.initials: X
authors.lastname: Zhang
authors.forename: Chengwei
authors.initials: C
authors.lastname: Wang
authors.forename: Jianbiao
authors.initials: J
authors.lastname: Chen
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhu
authors.forename: Aizhen
authors.initials: A
authors.lastname: Liao
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Ma
keywords: TiO2 nanotube; conductivity; effective work function; field emission; oxygen vacancy