title: Broadband coherent emission observed in polycrystalline CdSSe nanowires under high excitation.
abstract: Polycrystalline CdSSe nanowires were prepared with a low-temperature physical evaporation method. Structural analysis combining HRTEM with XRD demonstrate that these as-prepared wires have a hexagonal wurtzite structure with a polycrystalline nature. Locally excited optical measurements show that though these wires can still act as waveguide cavities, their polycrystalline nature will induce a significant redshift of the emitted light during its transportation along them. Power dependent photoluminescence measurement shows that these polycrystalline wires can achieve broadband coherent emission at the band-edge band under high excitation, which shows marked contrast with the much narrower and multimode spectra observed in the single-crystalline nanowires with the same elemental composition. Time-resolved photoluminescence further confirms the occurrence of coherent emission in these wires, which originates from the electron-hole plasma (EHP) recombination of high-density carriers generated under high excitation. These kinds of polycrystalline alloy nanowires with broadband coherent emission should have potential uses in nano-scaled wavelength tunable light-emitting devices.
authors.affiliation: School of MSE, Beijing Institute of Technology, Beijing 100081, People's Republic of China. Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education and Micro-Nanotechnology Research Center, Hunan University, Changsha 410082, People's Republic of China.
authors.forename: R B
authors.initials: RB
authors.lastname: Liu
authors.forename: J H
authors.initials: JH
authors.lastname: Cao
authors.forename: Z A
authors.initials: ZA
authors.lastname: Li
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: Q L
authors.initials: QL
authors.lastname: Zhang
authors.forename: P B
authors.initials: PB
authors.lastname: He
authors.forename: B S
authors.initials: BS
authors.lastname: Zou
authors.forename: A L
authors.initials: AL
authors.lastname: Pan