Adhesion, Stiffness, and Instability in Atomically Thin MoS<sub>2</sub> Bubbles.

Lloyd, David; Liu, Xinghui; Boddeti, Narasimha; Cantley, Lauren; Long, Rong; Dunn, Martin L; Bunch, J Scott · Nano Lett · 2017

basic_science · Level V

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Abstract

We measured the work of separation of single and few-layer MoS<sub>2</sub> membranes from a SiO<sub>x</sub> substrate using a mechanical blister test and found a value of 220 ± 35 mJ/m<sup>2</sup>. Our measurements were also used to determine the 2D Young's modulus (E<sub>2D</sub>) of a single MoS<sub>2</sub> layer to be 160 ± 40 N/m. We then studied the delamination mechanics of pressurized MoS<sub>2</sub> bubbles, demonstrating both stable and unstable transitions between the bubbles' laminated and delaminated states as the bubbles were inflated. When they were deflated, we observed edge pinning and a snap-in transition that are not accounted for by the previously reported models. We attribute this result to adhesion hysteresis and use our results to estimate the work of adhesion of our membranes to be 42 ± 20 mJ/m<sup>2</sup>.