title: Fabrication and temperature-dependent field-emission properties of bundlelike VO2 nanostructures.
abstract: Bundlelike VO(2)(B) nanostructures were synthesized via a hydrothermal method, and VO(2)(M(1)/R) nanobundles were obtained after a heat-treatment process. Structural characterization shows that these nanobundles are self-assembled by VO(2) nanowires, and VO(2)(M(1)/R) nanobundles have better crystallinity. Temperature-dependent field-emission (FE) measurement indicates that FE properties of these two phases of nanobundles can both be improved by increasing the ambient temperature. Moreover, for the VO(2)(M(1)/R) nanobundles, their FE properties are also strongly dependent on the temperature-induced metal-insulator transitions process. Compared with poor FE properties found in the insulating phase, FE properties were significantly improved by increasing the temperature, and about a three-orders-of-magnitude increasing of the emission current density has been observed at a fixed field of 6 V/μm. Work function measurement and density-functional theory calculations indicated that the decrease of work function with temperature is the main reason that caused the improvement of FE properties. These characteristics make VO(2)(M(1)/R) a candidate material for application of new type of temperature-controlled field emitters, whose emission density can be adjusted by ambient temperature.
authors.affiliation: Key Laboratory of Polar Materials and Devices (Ministry of Education of China), Department of Electronic Engineering, East China Normal University, Shanghai 200241, China.
authors.forename: Haihong
authors.initials: H
authors.lastname: Yin
authors.forename: Min
authors.initials: M
authors.lastname: Luo
authors.forename: Ke
authors.initials: K
authors.lastname: Yu
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Gao
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.forename: Zhengli
authors.initials: Z
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Zeng
authors.forename: Chuanxiang
authors.initials: C
authors.lastname: Cao
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Zhu