title: Tailoring hot-exciton emission and lifetimes in semiconducting nanowires via whispering-gallery nanocavity plasmons.
abstract: The manipulation of radiative properties of light emitters coupled with surface plasmons is important for engineering new nanoscale optoelectronic devices, including lasers, detectors and single photon emitters. However, so far the radiative rates of excited states in semiconductors and molecular systems have been enhanced only moderately, typically by a factor of 10-50, producing emission mostly from thermalized excitons. Here, we show the generation of dominant hot-exciton emission, that is, luminescence from non-thermalized excitons that are enhanced by the highly concentrated electromagnetic fields supported by the resonant whispering-gallery plasmonic nanocavities of CdS-SiO(2)-Ag core-shell nanowire devices. By tuning the plasmonic cavity size to match the whispering-gallery resonances, an almost complete transition from thermalized exciton to hot-exciton emission can be achieved, which reflects exceptionally high radiative rate enhancement of >10(3) and sub-picosecond lifetimes. Core-shell plasmonic nanowires are an ideal test bed for studying and controlling strong plasmon-exciton interaction at the nanoscale and opens new avenues for applications in ultrafast nanophotonic devices.
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Chang-Hee
authors.initials: CH
authors.lastname: Cho
authors.forename: Carlos O
authors.initials: CO
authors.lastname: Aspetti
authors.forename: Michael E
authors.initials: ME
authors.lastname: Turk
authors.forename: James M
authors.initials: JM
authors.lastname: Kikkawa
authors.forename: Sung-Wook
authors.initials: SW
authors.lastname: Nam
authors.forename: Ritesh
authors.initials: R
authors.lastname: Agarwal
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry; D017097:Electric Impedance; D008027:Light; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires; D055620:Optical Phenomena; D012666:Semiconductors; D012822:Silicon Dioxide / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D019187:Cadmium Compounds; D013431:Sulfates; D013440:Sulfides; C034939:cadmium sulfide; D012834:Silver; D012822:Silicon Dioxide