Fig. 2: Successful monolayer CVD-graphene COC structures.
From: Definitive engineering strength and fracture toughness of graphene through on-chip nanomechanics
a General view of an asymmetric structure in which a crack is initiated and propagated in a brittle way. b Closer view of an asymmetric structure shows a large crack tip opening displacement and the crack arrested after propagating over a significant distance. c Another asymmetric COC where the out-of-plane displacement is more evident, with a zoomed view (on the left side) showing the border between the notch and the crack. Strictly speaking, on the upper side of the notch, one can observe a kind of step marking the border between the notch and the initiated crack. d A general view of a successful symmetric configuration. e A zoomed view of the crack in a symmetric configuration where the crack opening is narrower on the left side compared with the right one- both crack lengths are close, and the cracking direction is similar. Red scale bar, 10 µm and white scale bar 2 µm.
