title: Characteristic Work Function Variations of Graphene Line Defects.
abstract: Line defects, including grain boundaries and wrinkles, are commonly seen in graphene grown by chemical vapor deposition. These one-dimensional defects are believed to alter the electrical and mechanical properties of graphene. Unfortunately, it is very tedious to directly distinguish grain boundaries from wrinkles due to their similar morphologies. In this report, high-resolution Kelvin potential force microscopy (KPFM) is employed to measure the work function distribution of graphene line defects. The characteristic work function variations of grain boundaries, standing-collapsed wrinkles, and folded wrinkles could be clearly identified. Classical and quantum molecular dynamics simulations reveal that the unique work function distribution of each type of line defects is originated from the doping effect induced by the SiO2 substrate. Our results suggest that KPFM can be an easy-to-use and accurate method to detect graphene line defects, and also propose the possibility to tune the graphene work function by defect engineering.
authors.affiliation: Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49931, United States.
authors.forename: Fei
authors.initials: F
authors.lastname: Long
authors.forename: Poya
authors.initials: P
authors.lastname: Yasaei
authors.forename: Raj
authors.initials: R
authors.lastname: Sanoj
authors.affiliation: Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49931, United States.
authors.forename: Wentao
authors.initials: W
authors.lastname: Yao
authors.forename: Petr
authors.initials: P
authors.lastname: Král
authors.forename: Amin
authors.initials: A
authors.lastname: Salehi-Khojin
authors.affiliation: Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University , Houghton, Michigan 49931, United States.
authors.forename: Reza
authors.initials: R
authors.lastname: Shahbazian-Yassar
keywords: atomic force microscopy; density functional theory; graphene; line defects; work function