The mechanical characterization of stacked, multilayer graphene cantilevers and plates

Abstract

The mechanical properties of stacked graphene sheets with varying number of layers are examined. The stacked sheets are assembled by manually combining single layer CVD-grown graphene monolayers, resulting in a turbostratic multilayer graphene with irregular layer spacings greater than crystalline graphite. Due to the presence of multiple layers, the material is analyzed as a plate rather than a membrane. Bending stiffness is determined via the deflection of micron-scale cantilevers, prepared using focused ion beam milling, while in-plane tensile stiffness is characterized through center-loading of edge-supported circular specimens. Computational modeling and established analytical solutions are used to extract material and structural property information, and benchmark measured properties relative to complementary results from indentation tests. Stacked, few-layer CVD-grown graphene retains an in-plane elastic modulus of 350N/m/layer (corresponding to 1.04 TPa for an inter-layer spacing of 0.335nm), suggesting good load-sharing between stacked layers. Width-normalized bending stiffness was unmeasurable for cantilevers of 1 and 3 layers, while cantilevers of 5 and 10 layers had values of 11,100nN·nm and 1.3×106nN·nm respectively.

Capacitive pressure sensing with suspended graphene–polymer heterostructure membranes

“…Another strategy in preventing the collapse of suspended graphene is to reinforce membranes with another material. [30][31][32] For example, by stacking up multiple layers of CVD graphene on top of one another or by depositing carbon nanotubes on a graphene film, crack-free freestanding structures up to 1.5 mm in diameter and 5.1 nm thickness have been demonstrated. 33,34 However, this approach requires many fabrication steps, is very time consuming and results in wrinkling of the suspended membranes.…”