title: Polymer-free patterning of graphene at sub-10-nm scale by low-energy repetitive electron beam.
abstract: A polymer-free technique for generating nanopatterns on both synthesized and exfoliated graphene sheets is proposed and demonstrated. A low-energy (5-30 keV) scanning electron beam with variable repetition rates is used to etch suspended and unsuspended graphene sheets on designed locations. The patterning mechanisms involve a defect-induced knockout process in the initial etching stage and a heat-induced curling process in a later stage. Rough pattern edges appear due to inevitable stochastic knockout of carbon atoms or graphene structure imperfection and can be smoothed by thermal annealing. By using this technique, the minimum feature sizes achieved are about 5 nm for suspended and 7 nm for unsuspended graphene. This study demonstrates a polymer-free direct nanopatterning approach for graphene.
authors.affiliation: Institute of Physics, Academia Sinica, Taipei, 115, Taiwan; Institute of Atomic and Molecular Science, Academia Sinica, Taipei, 115, Taiwan.
authors.forename: Yann-Wen
authors.initials: YW
authors.lastname: Lan
authors.forename: Wen-Hao
authors.initials: WH
authors.lastname: Chang
authors.forename: Bo-Tang
authors.initials: BT
authors.lastname: Xiao
authors.forename: Bo-Wei
authors.initials: BW
authors.lastname: Liang
authors.forename: Jyun-Hong
authors.initials: JH
authors.lastname: Chen
authors.forename: Pei-hsun
authors.initials: PH
authors.lastname: Jiang
authors.forename: Lain-Jong
authors.initials: LJ
authors.lastname: Li
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Su
authors.forename: Yuan-Liang
authors.initials: YL
authors.lastname: Zhong
authors.forename: Chii-Dong
authors.initials: CD
authors.lastname: Chen
keywords: defect-induced knockout; electron beams; graphene nanoribbons; graphene transfers; heat-induced curling; polymer-free