Degenerate n-Doping of Few-Layer Transition Metal Dichalcogenides by Potassium

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• 作者：Hui Fang ; Mahmut Tosun ; Gyungseon Seol ; Ting Chia Chang ; Kuniharu Takei ; Jing Guo ; Ali Javey
• 刊名：Nano Letters
• 出版年：2013
• 出版时间：May 8, 2013
• 年：2013
• 卷：13
• 期：5
• 页码：1991-1995
• 全文大小：360K
• 年卷期：v.13,no.5(May 8, 2013)
• ISSN：1530-6992

文摘

We report here the first degenerate n-doping of few-layer MoS₂ and WSe₂ semiconductors by surface charge transfer using potassium. High-electron sheet densities of 1.0 脳 10¹³ cm^鈥? and 2.5 脳 10¹² cm^鈥? for MoS₂ and WSe₂ are obtained, respectively. In addition, top-gated WSe₂ and MoS₂ n-FETs with selective K doping at the metal source/drain contacts are fabricated and shown to exhibit low contact resistances. Uniquely, WSe₂ n-FETs are reported for the first time, exhibiting an electron mobility of 110 cm²/V路s, which is comparable to the hole mobility of previously reported p-FETs using the same material. Ab initio simulations were performed to understand K doping of MoS₂ and WSe₂ in comparison with graphene. The results here demonstrate the need of degenerate doping of few-layer chalcogenides to improve the contact resistances and further realize high performance and complementary channel electronics.

Keywords:

Degenerate doping; few-layer; TMDCs; MoS₂; WSe₂; potassium; surface charge transfer