Reducing Extrinsic Performance-Limiting Factors in Graphene Grown by Chemical Vapor Deposition

详细信息    查看全文

• 作者：Jack Chan ; Archana Venugopal ; Adam Pirkle ; Stephen McDonnell ; David Hinojos ; Carl W. Magnuson ; Rodney S. Ruoff ; Luigi Colombo ; Robert M. Wallace ; Eric M. Vogel
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：April 24, 2012
• 年：2012
• 卷：6
• 期：4
• 页码：3224-3229
• 全文大小：422K
• 年卷期：v.6,no.4(April 24, 2012)
• ISSN：1936-086X

文摘

Field-effect transistors fabricated on graphene grown by chemical vapor deposition (CVD) often exhibit large hysteresis accompanied by low mobility, high positive backgate voltage corresponding to the minimum conductivity point (V_min), and high intrinsic carrier concentration (n₀). In this report, we show that the mobility reported to date for CVD graphene devices on SiO₂ is limited by trapped water between the graphene and SiO₂ substrate, impurities introduced during the transfer process and adsorbates acquired from the ambient. We systematically study the origin of the scattering impurities and report on a process which achieves the highest mobility (渭) reported to date on large-area devices for CVD graphene on SiO₂: maximum mobility (渭_max) of 7800 cm²/(V路s) measured at room temperature and 12鈥?00 cm²/(V路s) at 77 K. These mobility values are close to those reported for exfoliated graphene on SiO₂ and can be obtained through the careful control of device fabrication steps including minimizing resist residue and non-aqueous transfer combined with annealing. It is also observed that CVD graphene is prone to adsorption of atmospheric species, and annealing at elevated temperature in vacuum helps remove these species.

Keywords:

graphene; transistor; chemical vapor deposition; mobility; scattering