Comparative study between the fracture stress of poly- and single-crystalline graphene using a novel nanoelectromechanical system structure

• Published in: Micro & nano letters Vol. 12; no. 11; pp. 907 - 912
• Main Authors: Ng, Jimmy, Chen, Qi, Xie, Ya-Hong, Wang, Albert, Wu, Tianru
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 01.11.2017; John Wiley & Sons, Inc
• Subjects: Brittleness; Chemical vapor deposition; chemical vapour deposition; Crystal growth; Crystal structure; Crystallinity; electromechanical responses; electrostatical actuation; Finite element method; fracture; fracture stress; Fracture toughness; Grain boundaries; Graphene; graphene devices; graphene sheet; hnite element simulations; local feeding CVD; Mechanical properties; monolayer graphene; monolayers; nail structures; nanoelectromechanical devices; Nanoelectromechanical systems; novel nanoelectromechanical system structure; novel NEMS structure; polycrystalline graphene; Single crystals; single‐crystalline graphene; Special Issue: Selected Papers from The 12th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2017); Stresses; suspended graphene ribbon devices; two‐dimensional carbon material; monolayer graphene; electromechanical responses; C; grain boundaries; monolayers; two-dimensional carbon material; polycrystalline graphene; graphene; mechanical properties; fracture; electrostatical actuation; novel nanoelectromechanical system structure; suspended graphene ribbon devices; chemical vapour deposition; graphene sheet; local feeding CVD; fracture stress; nail structures; hnite element simulations; novel NEMS structure; single-crystalline graphene; graphene devices; nanoelectromechanical devices
• ISSN: 1750-0443; 1750-0443
• DOI: 10.1049/mnl.2017.0422

Graphene is a two-dimensional carbon material with extraordinary mechanical properties. However, recent studies have found that the presence of grain boundaries significantly decreases fracture stress of graphene, warranting further investigation. This work reports the development of a new method to measure the fracture stress of monolayer graphene with a novel nanoelectromechanical system (NEMS) structure. Suspended graphene ribbon devices with a range of geometries were electrostatically actuated while the graphene sheet was pinned down with various nail structures. By recording the electromechanical responses at fracture and using finite element simulations, the fracture stress was calculated. Using this novel NEMS structure, the fracture stress of polycrystalline graphene grown using conventional chemical vapour deposition (CVD) and single-crystalline graphene grown using local feeding CVD were found to be ∼30 and ∼90 GPa, respectively.