title: Room-temperature high on/off ratio in suspended graphene nanoribbon field-effect transistors.
abstract: We have fabricated suspended few-layer (1-3 layers) graphene nanoribbon field-effect transistors from unzipped multi-wall carbon nanotubes. Electrical transport measurements show that current annealing effectively removes the impurities on the suspended graphene nanoribbons, uncovering the intrinsic ambipolar transfer characteristic of graphene. Further increasing the annealing current creates a narrow constriction in the ribbon, leading to the formation of a large bandgap and subsequent high on/off ratio (which can exceed 10(4)). Such fabricated devices are thermally and mechanically stable: repeated thermal cycling has little effect on their electrical properties. This work shows for the first time that ambipolar field-effect characteristics and high on/off ratios at room temperature can be achieved in relatively wide graphene nanoribbons (15-50 nm) by controlled current annealing.
authors.affiliation: Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Ming-Wei
authors.initials: MW
authors.lastname: Lin
authors.forename: Cheng
authors.initials: C
authors.lastname: Ling
authors.forename: Yiyang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Hyeun Joong
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Mark Ming-Cheng
authors.initials: MM
authors.lastname: Cheng
authors.forename: Luis A
authors.initials: LA
authors.lastname: Agapito
authors.forename: Nicholas
authors.initials: N
authors.lastname: Kioussis
authors.forename: Noppi
authors.initials: N
authors.lastname: Widjaja
authors.forename: Zhixian
authors.initials: Z
authors.lastname: Zhou