Nanoimprint-Assisted Shear Exfoliation (NASE) for Producing Multilayer MoS2 Structures as Field-Effect Transistor Channel Arrays.

MoS2 and other semiconducting transition metal dichalcogenides (TMDCs) are of great interest due to their excellent physical properties and versatile chemistry. Although many recent research efforts have been directed to explore attractive properties associated with MoS2 monolayers, multilayer/few-layer MoS2 structures are indeed demanded by many practical scale-up device applications, because multilayer structures can provide sizable electronic/photonic state densities for driving upscalable electrical/optical signals. Currently there is a lack of processes capable of producing ordered, pristine multilayer structures of MoS2 (or other relevant TMDCs) with manufacturing-grade uniformity of thicknesses and electronic/photonic properties. In this article, we present a nanoimprint-based approach toward addressing this challenge. In this approach, termed as nanoimprint-assisted shear exfoliation (NASE), a prepatterned bulk MoS2 stamp is pressed into a polymeric fixing layer, and the imprinted MoS2 features are exfoliated along a shear direction. This shear exfoliation can significantly enhance the exfoliation efficiency and thickness uniformity of exfoliated flakes in comparison with previously reported exfoliation processes. Furthermore, we have preliminarily demonstrated the fabrication of multiple transistors and biosensors exhibiting excellent device-to-device performance consistency. Finally, we present a molecular dynamics modeling analysis of the scaling behavior of NASE. This work holds significant potential to leverage the superior properties of MoS2 and other emerging TMDCs for practical scale-up device applications.