title: Plasmon-enhanced ultraviolet photoluminescence from hybrid structures of graphene/ZnO films.
abstract: We report substantially enhanced photoluminescence (PL) from hybrid structures of graphene/ZnO films at a band gap energy of ZnO (∼3.3  eV/376  nm). Despite the well-known constant optical conductivity of graphene in the visible-frequency regime, its abnormally strong absorption in the violet-frequency region has recently been reported. In this Letter, we demonstrate that the resonant excitation of graphene plasmon is responsible for such absorption and eventually contributes to enhanced photoemission from structures of graphene/ZnO films when the corrugation of the ZnO surface modulates photons emitted from ZnO to fulfill the dispersion relation of graphene plasmon. These arguments are strongly supported by PL enhancements depending on the spacer thickness, measurement temperature, and annealing temperature, and the micro-PL mapping images obtained from separate graphene layers on ZnO films.
authors.affiliation: Department of Applied Physics, College of Applied Science, Kyung Hee University, Yongin 446-701, Korea.
authors.forename: Sung Won
authors.initials: SW
authors.lastname: Hwang
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Shin
authors.forename: Chang Oh
authors.initials: CO
authors.lastname: Kim
authors.forename: Seung Hui
authors.initials: SH
authors.lastname: Hong
authors.forename: Min Choul
authors.initials: MC
authors.lastname: Kim
authors.forename: Jungkil
authors.initials: J
authors.lastname: Kim
authors.forename: Keun Yong
authors.initials: KY
authors.lastname: Lim
authors.forename: Sung
authors.initials: S
authors.lastname: Kim
authors.forename: Suk-Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Kwang Jun
authors.initials: KJ
authors.lastname: Ahn
authors.forename: Gunn
authors.initials: G
authors.lastname: Kim
authors.forename: Sung Hyun
authors.initials: SH
authors.lastname: Sim
authors.forename: Byung Hee
authors.initials: BH
authors.lastname: Hong