title: Monolayer graphene film on ZnO nanorod array for high-performance Schottky junction ultraviolet photodetectors.
abstract: A new Schottky junction ultraviolet photodetector (UVPD) is fabricated by coating a free-standing ZnO nanorod (ZnONR) array with a layer of transparent monolayer graphene (MLG) film. The single-crystalline [0001]-oriented ZnONR array has a length of about 8-11 μm, and a diameter of 100∼600 nm. Finite element method (FEM) simulation results show that this novel nanostructure array/MLG heterojunction can trap UV photons effectively within the ZnONRs. By studying the I-V characteristics in the temperature range of 80-300 K, the barrier heights of the MLG film/ZnONR array Schottky barrier are estimated at different temperatures. Interestingly, the heterojunction diode with typical rectifying characteristics exhibits a high sensitivity to UV light illumination and a quick response of millisecond rise time/fall times with excellent reproducibility, whereas it is weakly sensitive to visible light irradiation. It is also observed that this UV photodetector (PD) is capable of monitoring a fast switching light with a frequency as high as 2250 Hz. The generality of the above results suggest that this MLG film/ZnONR array Schottky junction UVPD will have potential application in future optoelectronic devices.
authors.affiliation: School of Electronic Science and Applied Physics and Anhui Provincial Key Laboratory of Advanced Functional, Materials and Devices, Hefei University of Technology, Hefei, Anhui 230009, PR China.
authors.forename: Biao
authors.initials: B
authors.lastname: Nie
authors.forename: Ji-Gang
authors.initials: JG
authors.lastname: Hu
authors.forename: Lin-Bao
authors.initials: LB
authors.lastname: Luo
authors.forename: Chao
authors.initials: C
authors.lastname: Xie
authors.forename: Long-Hui
authors.initials: LH
authors.lastname: Zeng
authors.forename: Peng
authors.initials: P
authors.lastname: Lv
authors.forename: Fang-Ze
authors.initials: FZ
authors.lastname: Li
authors.forename: Jian-Sheng
authors.initials: JS
authors.lastname: Jie
authors.forename: Mei
authors.initials: M
authors.lastname: Feng
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Wu
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: Yu
authors.forename: Shu-Hong
authors.initials: SH
authors.lastname: Yu
mesh_terms: D006108:Graphite / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000191:economics*; D014466:Ultraviolet Rays; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D006108:Graphite; D015034:Zinc Oxide
keywords: Schottky barriers; ZnO nanorod arrays; graphene; light trapping; photodetectors