Air-Stable n-Doping of WSe2 by Anion Vacancy Formation with Mild Plasma Treatment

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• 作者：Mahmut Tosun ; Leslie Chan ; Matin Amani ; Tania Roy ; Geun Ho Ahn ; Peyman Taheri ; Carlo Carraro ; Joel W. Ager ; Roya Maboudian ; Ali Javey
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：July 26, 2016
• 年：2016
• 卷：10
• 期：7
• 页码：6853-6860
• 全文大小：549K
• 年卷期：0
• ISSN：1936-086X

文摘

Transition metal dichalcogenides (TMDCs) have been extensively explored for applications in electronic and optoelectronic devices due to their unique material properties. However, the presence of large contact resistances is still a fundamental challenge in the field. In this work, we study defect engineering by using a mild plasma treatment (He or H₂) as an approach to reduce the contact resistance to WSe₂. Material characterization by X-ray photoelectron spectroscopy, photoluminescence, and Kelvin probe force microscopy confirm defect-induced n-doping, up to degenerate level, which is attributed to the creation of anion (Se) vacancies. The plasma treatment is adopted in the fabrication process flow of WSe₂ n-type metal-oxide–semiconductor field-effect transistors to selectively create anion vacancies at the metal contact regions. Due to lowering the metal contact resistance, improvements in the device performance metrics such as a 20× improvement in ON current and a nearly ideal subthreshold swing value of 66 mV/dec are observed. This work demonstrates that defect engineering at the contact regions can be utilized as a reliable scheme to realize high-performance electronic and optoelectronic TMDC devices.