Air-Stable Surface Charge Transfer Doping of MoS2 by Benzyl Viologen

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• 作者：Daisuke Kiriya ; Mahmut Tosun ; Peida Zhao ; Jeong Seuk Kang ; Ali Javey
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：June 4, 2014
• 年：2014
• 卷：136
• 期：22
• 页码：7853-7856
• 全文大小：278K
• 年卷期：v.136,no.22(June 4, 2014)
• ISSN：1520-5126

文摘

Air-stable doping of transition metal dichalcogenides is of fundamental importance to enable a wide range of optoelectronic and electronic devices while exploring their basic material properties. Here we demonstrate the use of benzyl viologen (BV), which has one of the highest reduction potentials of all electron-donor organic compounds, as a surface charge transfer donor for MoS₂ flakes. The n-doped samples exhibit excellent stability in both ambient air and vacuum. Notably, we obtained a high electron sheet density of 1.2 脳 10¹³ cm^鈥?, which corresponds to the degenerate doping limit for MoS₂. The BV dopant molecules can be reversibly removed by immersion in toluene, providing the ability to control the carrier sheet density as well as selective removal of surface dopants on demand. By BV doping of MoS₂ at the metal junctions, the contact resistances are shown to be reduced by a factor of >3. As a proof of concept, top-gated field-effect transistors were fabricated with BV-doped n⁺ source/drain contacts self-aligned with respect to the top gate. The device architecture, resembling that of the conventional Si transistors, exhibited excellent switching characteristics with a subthreshold swing of 77 mV/decade.