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Nano Research

Article Title

Significantly enhanced optoelectronic performance of tungsten diselenide phototransistor via surface functionalization

Authors

Bo Lei, Department of Physics, National University of Singapore, Singapore 117542, Singapore Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
Zehua Hu, Department of Physics, National University of Singapore, Singapore 117542, Singapore Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
Du Xiang, Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
Junyong Wang, Department of Physics, National University of Singapore, Singapore 117542, Singapore Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
Goki Eda, Department of Physics, National University of Singapore, Singapore 117542, Singapore Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
Cheng Han, Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore Department of Chemistry, National University of Singapore, Singapore 117543, Singapore SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Shenzhen University, Shenzhen 518060, China
Wei Chen, Department of Physics, National University of Singapore, Singapore 117542, Singapore Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore Department of Chemistry, National University of Singapore, Singapore 117543, Singapore SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Shenzhen University, Shenzhen 518060, China National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, Suzhou 215123, China

Keywords

WSe2, in situ surface transfer doping, performance enhancement, phototransistor, cesium carbonate

Abstract

ABSTRACT Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have attracted enormous research interests and efforts towards the development of versatile electronic and optical devices, owing to their extraordinary and unique fundamental properties and remarkable prospects in nanoelectronic applications. Among the TMDs, tungsten diselenide (WSe2) exhibits tunable ambipolar transport characteristics and superior optical properties such as high quantum efficiency. Herein, we demonstrate significant enhancement in the device performance of WSe2 phototransistor by in situ surface functionalization with cesium carbonate (Cs2CO3). WSe2 was found to be strongly doped with electrons after Cs2CO3 modification. The electron mobility of WSe2 increased by almost one order of magnitude after surface functionalization with 1.6-nm-thick Cs2CO3 decoration. Furthermore, the photocurrent of the WSe2-based phototransistor increased by nearly three orders of magnitude with the deposition of 1.6-nm-thick Cs2CO3. Characterizations by in situ photoelectron spectroscopy techniques confirmed the significant surface charge transfer occurring at the Cs2CO3/WSe2 interface. Our findings coupled with the tunable nature of the surface transfer doping method establish WSe2 as a promising candidate for future 2D materialsbased optoelectronic devices.

Graphical Abstract

Publisher

Tsinghua University Press

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