title: Raman scattering and efficient UV photoluminescence from well-aligned ZnO nanowires epitaxially grown on GaN buffer layer.
abstract: Optical phonon confinement and efficient UV emission of ZnO nanowires were investigated in use of resonant Raman scattering (RRS) and photoluminescence (PL). The high-quality ZnO nanowires with diameters of 80-100 nm and lengths of several micrometers were epitaxially grown through a simple low-pressure vapor-phase deposition method at temperature 550 degrees C on the precoated GaN(0001) buffer layer. The increasing intensity ratio of n-order longitudinal optical (LO) phonon (A(1)(nLO)/E(1)(nLO)) with increasing scattering order in RRS reveals the phonon quantum confinement as shrinking the diameter of ZnO nanowires. The exciton-related recombination near the band-edge transition dominate the UV emissions at room temperature as well as at low temperature that exhibits almost no other nonstoichiometric defects in the ZnO nanowires.
authors.affiliation: Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Tahsueh Road, Hsinchu 30050, Taiwan.
authors.forename: Hsin-Ming
authors.initials: HM
authors.lastname: Cheng
authors.forename: Hsu-Cheng
authors.initials: HC
authors.lastname: Hsu
authors.forename: Yung-Kuan
authors.initials: YK
authors.lastname: Tseng
authors.forename: Li-Jiaun
authors.initials: LJ
authors.lastname: Lin
authors.forename: Wen-Feng
authors.initials: WF
authors.lastname: Hsieh