Ultrafast Dynamics of Metal Plasmons Induced by 2D Semiconductor Excitons in Hybrid Nanostructure Arrays

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• 作者：Abdelaziz BoulesbaaViktoriia E. Babicheva ; Kai WangIvan I. Kravchenko ; Ming-Wei Lin ; Masoud Mahjouri-Samani ; Christopher B. Jacobs ; Alexander A. Puretzky ; Kai XiaoIlia Ivanov ; Christopher M. Rouleau ; David B. Geohegan
• 刊名：ACS Photonics
• 出版年：2016
• 出版时间：December 21, 2016
• 年：2016
• 卷：3
• 期：12
• 页码：2389-2395
• 全文大小：628K
• ISSN：2330-4022

文摘

With the advanced progress achieved in the field of nanotechnology, localized surface plasmon resonances are actively considered to improve the efficiency of metal-based photocatalysis, photodetection, and photovoltaics. Here, we report on the exchange of energy and electric charges in a hybrid composed of a two-dimensional tungsten disulfide (2D-WS₂) monolayer and an array of aluminum (Al) nanodisks. Femtosecond pump–probe spectroscopy results indicate that within ∼830 fs after photoexcitation of the 2D-WS₂ semiconductor energy transfer from the 2D-WS₂ excitons excites the plasmons of the Al array. Then, upon the radiative and/or nonradiative damping of these excited plasmons, energy and/or electron transfer back to the 2D-WS₂ semiconductor takes place as indicated by an increase in the reflected probe at the 2D-exciton transition energies at later time delays. This simultaneous exchange of energy and charges between the metal and the 2D-WS₂ semiconductor resulted in an extension of the average lifetime of the 2D-excitons from ∼15 ps to ∼58 ps in the absence and presence of the Al array, respectively. Furthermore, the indirectly excited plasmons were found to live as long as the 2D-WS₂ excitons exist. The demonstrated ability to generate exciton–plasmon coupling in a hybrid nanostructure may open new opportunities for optoelectronic applications such as plasmonic-based photodetection and photocatalysis.