title: Surface modification effect on photoluminescence of individual ZnO nanorods with different diameters.
abstract: Optical properties of Al2O3 coated individual ZnO nanorods (NRs) with different diameters were studied by confocal micro-photoluminescence spectroscopy. The one-dimensional ZnO/Al2O3 core-shell NRs showed enhanced near band-edge emission compared with the same ZnO NRs before Al2O3 coating at room temperature. Besides, the relative intensity of the deep-level emission with respect to the near band-edge emission was reduced. A model was proposed to explain these spectral changes. For ZnO NRs with diameters above 360 nm, a multi-mode behavior resulting from whispering gallery resonance was observed. In addition, selective enhancement or quenching of different whispering gallery modes in ultraviolet (UV) emission was observed after Al2O3 coating at room temperature, which is due to the larger refractive index of Al2O3 compared with air. We proposed a model to explain these spectral changes as well. By comparing the optical properties before and after surface coating, our results suggest that surface coating of an Al2O3 layer is an effective way to tailor the optical properties of ZnO NRs.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China.
authors.forename: Duan
authors.initials: D
authors.lastname: Zhao
authors.forename: Xiaoxian
authors.initials: X
authors.lastname: Zhang
authors.forename: Haibo
authors.initials: H
authors.lastname: Dong
authors.forename: Leijing
authors.initials: L
authors.lastname: Yang
authors.forename: Qingsheng
authors.initials: Q
authors.lastname: Zeng
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Li
authors.forename: Le
authors.initials: L
authors.lastname: Cai
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Pingshan
authors.initials: P
authors.lastname: Luan
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Min
authors.initials: M
authors.lastname: Tu
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Weiya
authors.initials: W
authors.lastname: Zhou
authors.forename: Sishen
authors.initials: S
authors.lastname: Xie