title: Giant photoluminescence enhancement in tungsten-diselenide-gold plasmonic hybrid structures.
abstract: Impressive properties arise from the atomically thin nature of transition metal dichalcogenide two-dimensional materials. However, being atomically thin limits their optical absorption or emission. Hence, enhancing their photoluminescence by plasmonic nanostructures is critical for integrating these materials in optoelectronic and photonic devices. Typical photoluminescence enhancement from transition metal dichalcogenides is 100-fold, with recent enhancement of 1,000-fold achieved by simultaneously enhancing absorption, emission and directionality of the system. By suspending WSe2 flakes onto sub-20-nm-wide trenches in gold substrate, we report a giant photoluminescence enhancement of ∼20,000-fold. It is attributed to an enhanced absorption of the pump laser due to the lateral gap plasmons confined in the trenches and the enhanced Purcell factor by the plasmonic nanostructure. This work demonstrates the feasibility of giant photoluminescence enhancement in WSe2 with judiciously designed plasmonic nanostructures and paves a way towards the implementation of plasmon-enhanced transition metal dichalcogenide photodetectors, sensors and emitters.
authors.affiliation: NUS Graduate School for Integrative Sciences &Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.|Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.|Department of Physics, Imperial College London, London SW7 2AZ, UK.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore.
authors.forename: Zhaogang
authors.initials: Z
authors.lastname: Dong
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
authors.forename: Yinghong
authors.initials: Y
authors.lastname: Gu
authors.affiliation: Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Yung-Huang
authors.initials: YH
authors.lastname: Chang
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Lain-Jong
authors.initials: LJ
authors.lastname: Li
authors.affiliation: Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
authors.forename: Weijie
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.|Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.|Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
authors.forename: Goki
authors.initials: G
authors.lastname: Eda
authors.affiliation: Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.|SZU-NUS Collaborative Innovation Center for Optoelectronic Science &Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Physics, Imperial College London, London SW7 2AZ, UK.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Grinblat
authors.affiliation: Department of Physics, Imperial College London, London SW7 2AZ, UK.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Maier
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore.|Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
authors.forename: Joel K W
authors.initials: JK
authors.lastname: Yang
authors.affiliation: NUS Graduate School for Integrative Sciences &Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.|Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Qiu
authors.affiliation: NUS Graduate School for Integrative Sciences &Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.|Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.|Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
authors.forename: Andrew T S
authors.identifier: 0000-0002-5828-4312
authors.initials: AT
authors.lastname: Wee