Abstract
Plasmon-exciton coupling mechanisms were studied in ZnO/MgO core-shell nanowires by comparing nanowires with and without a silver-nanoparticle coating. By varying the thickness of the MgO layer, it was possible to examine the distance-dependent plasmonic effects and elucidate the mechanisms responsible for enhancing the band-edge photoluminescence. The core-shell nanowires exhibited optical cavity effects as a function of MgO thickness that dramatically enhanced the band-edge photoluminescence yields in the ultraviolet. Decorating the core-shell nanowires with Ag nanoparticles resulted in a two-fold plasmonic enhancement of the band-edge emission compared to the resonant cavity effects alone. In this case, an additional differential enhancement of the band-edge emission is observed for the first higher-order mode compared to the lowest-order mode. The visible luminescence is not significantly enhanced and does not follow the trend of enhanced photoluminescence observed for the band-edge decay.
Original language | English |
---|---|
Pages (from-to) | 132-137 |
Number of pages | 6 |
Journal | Thin Solid Films |
Volume | 553 |
DOIs | |
State | Published - Feb 28 2014 |
Externally published | Yes |
Funding
DCM, CEM and RFH received support from the Office of Science, US Department of Energy ( DE-FG02-01ER45916 ). DCM and RRM gratefully acknowledge the financial support from the United States Department of Defense ( W911NF-11-1-0156 ), and the National Science Foundation NSF-CREST Center for the Physics and Chemistry of Materials ( HRD-0420516 ). ESB was supported by the Research Experience for Undergraduates program of the National Science Foundation at Vanderbilt University ( PHY-1005099 ). High-resolution STEM images in Fig. 2 -c were acquired using the Osiris transmission electron microscope supported by a grant from the National Science Foundation ( EPS 1004083 ). High-resolution SEM images in Fig. 2 -a and b were supplied by Kannatassen Appavoo.
Funders | Funder number |
---|---|
National Science Foundation NSF-CREST Center for the Physics and Chemistry of Materials | HRD-0420516 |
National Science Foundation | 1263045 |
U.S. Department of Defense | W911NF-11-1-0156 |
U.S. Department of Energy | DE-FG02-01ER45916 |
Office of Science | |
Vanderbilt University | EPS 1004083, PHY-1005099 |
Keywords
- Ag plasmons
- Core-shell nanowire
- Photoluminescence
- Plasmon-exciton coupling
- Resonant optical cavity
- ZnO excitons