Synthesis of WS2xSe2–2x Alloy Nanosheets with Composition-Tunable Electronic Properties

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• 作者：Xidong Duan ; Chen Wang ; Zheng Fan ; Guolin Hao ; Liangzhi Kou ; Udayabagya Halim ; Honglai Li ; Xueping Wu ; Yicheng Wang ; Jianhui Jiang ; Anlian Pan ; Yu Huang ; Ruqin Yu ; Xiangfeng Duan
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：January 13, 2016
• 年：2016
• 卷：16
• 期：1
• 页码：264-269
• 全文大小：446K
• ISSN：1530-6992

文摘

Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have recently emerged as a new class of atomically thin semiconductors for diverse electronic, optoelectronic, and valleytronic applications. To explore the full potential of these 2D semiconductors requires a precise control of their band gap and electronic properties, which represents a significant challenge in 2D material systems. Here we demonstrate a systematic control of the electronic properties of 2D-TMDs by creating mixed alloys of the intrinsically p-type WSe₂ and intrinsically n-type WS₂ with variable alloy compositions. We show that a series of WS_2xSe_2–2x alloy nanosheets can be synthesized with fully tunable chemical compositions and optical properties. Electrical transport studies using back-gated field effect transistors demonstrate that charge carrier types and threshold voltages of the alloy nanosheet transistors can be systematically tuned by adjusting the alloy composition. A highly p-type behavior is observed in selenium-rich alloy, which gradually shifts to lightly p-type, and then switches to lightly n-type characteristics with the increasing sulfur atomic ratio, and eventually evolves into highly n-doped semiconductors in sulfur-rich alloys. The synthesis of WS_2xSe_2–2x nanosheets with tunable optical and electronic properties represents a critical step toward rational design of 2D electronics with tailored spectral responses and device characteristics.