Electromechanical coupling in atomically thin MoS$_{2}$ and graphene
ORAL
Abstract
Nanoelectromechanical systems (NEMS) based on novel materials such as graphene and MoS$_{2}$ allow studying their electromechanical characteristics. Here, we incorporate single and bilayer MoS$_{2}$ and graphene into NEMS and investigated their electromechanical behavior. We observe a Strain-induced bandgap modulation in atomically thin MoS$_{2}$ membranes with a thickness dependent modulation rate. Finite element modeling is used to extract the piezoresistive gauge factor for MoS$_{2}$. In the case of graphene, deflection of monolayer graphene nanoribbons results in a linear increase in their electrical resistance where an upper limit is estimated for the gauge factor. Surprisingly, we observe oscillations in the electromechanical response of bilayer graphene. Our numerical simulations indicate that these oscillations arise from quantum mechanical interference in the transition region induced by sliding of individual graphene layers with respect to each other. Our results reveal that atomically thin MoS$_{2}$ membranes show strong piezoresistive effect, comparable to the state-of-the-art silicon sensors. Moreover, bilayer graphene conceals unexpectedly novel physics allowing the rare observation of room temperature electronic interference phenomena.
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