Chemically Driven Tunable Light Emission of Charged and Neutral Excitons in Monolayer WS2

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• 作者：Namphung Peimyoo ; Weihuang Yang ; Jingzhi Shang ; Xiaonan Shen ; Yanlong Wang ; Ting Yu
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：November 25, 2014
• 年：2014
• 卷：8
• 期：11
• 页码：11320-11329
• 全文大小：662K
• ISSN：1936-086X

文摘

Monolayer (1L) semiconducting transition metal dichacogenides (TMDs) possess remarkable physical and optical properties, promising for a wide range of applications from nanoelectronics to optoelectronics such as light-emitting and sensing devices. Here we report how the molecular adsorption can modulate the light emission and electrical properties of 1L WS₂. The dependences of trion and exciton emission on chemical doping are investigated in 1L WS₂ by microphotoluminescence (渭PL) measurements, where different responses are observed and simulated theoretically. The total PL is strongly enhanced when electron-withdrawing molecules adsorb on 1L WS₂, which is attributed to the increase of the exciton formation due to charge transfer. The electrical transport measurements of a 1L WS₂ field effect transistor elucidate the effect of the adsorbates on the conductivity, which give evidence for charge transfer between molecules and 1L WS₂. These findings open up many opportunities to manipulate the electrical and optical properties of two-dimensional TMDs, which are particularly important for developing optoelectronic devices for chemical and biochemical sensing applications.

Keywords:

tungstein disulfide; photoluminescence; exciton; trion; chemical doping; charge transfer