摘要
Top-down lithography techniques are needed for manufacturing uniform device structures based on emerging 2D-layered materials.Mechanical exfoliation approaches based on nanoimprint and nanoprint principles are capable of producing ordered arrays of multilayer transition metal dichalcogenide microstructures with a high uniformity of feature dimensions.In this study,we present a study on the applicability of nanoimprint-assisted shear exfoliation for generating ultrathin monolayer and few-layer MoS_(2) structures as well as the critical limits of feature dimensions produced via such nanoimprint and nanoprint-based processes.In particular,this work shows that give a lateral feature size of MoS_(2) structures that are pre-patterned on a bulk stamp,there exists a critical thickness or aspect ratio value,below which the exfoliated layered structures exhibit major defects.To exfoliate a highquality,uniform monolayer or few-layer structures,the characteristic lateral feature sizes of such structures need to be in the sub-100 nm regimes.In addition,the exfoliated MoS_(2) flakes of critical thicknesses exhibit prominent interlayer twisting features on their cleaved surfaces.Field-effect transistors made from these MoS_(2) flakes exhibit multiple(or quasi-analog-tunable)charge memory states.This work advances the knowledge regarding the limitations and application scope of nanoimprint and nanoprint processes in manufacturing nano/microstructures based on layered materials and provides a method for producing multi-bit charge memory devices.
基金
This work was supported by NSF grant#CMMI-1636132.
