Department of Mechanical Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
ACS Nano. 2015 Sep 22;9(9):8773-85. doi: 10.1021/acsnano.5b01715. Epub 2015 Aug 27.
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.
二硫化钼（MoS2）和其他半导体过渡金属二硫属化物（TMDCs）因其优异的物理性质和多功能化学性质而备受关注。尽管最近的许多研究工作都致力于探索与 MoS2 单层相关的诱人特性，但许多实际的规模化器件应用确实需要多层/少层 MoS2 结构，因为多层结构可以为驱动可扩展的电/光信号提供相当大的电子/光子态密度。目前，缺乏能够生产具有制造级均匀厚度和电子/光子特性的有序、原始多层 MoS2（或其他相关 TMDCs）结构的工艺。在本文中，我们提出了一种基于纳米压印的方法来解决这一挑战。在这种方法中，称为纳米压印辅助剪切剥离（NASE），在预图案化的大块 MoS2 压印模板被压入聚合物固定层中，然后沿着剪切方向对压印的 MoS2 特征进行剥离。与以前报道的剥离工艺相比，这种剪切剥离可以显著提高剥离薄片的剥离效率和厚度均匀性。此外，我们已经初步演示了制造具有出色器件间性能一致性的多个晶体管和生物传感器。最后，我们提出了 NASE 缩放行为的分子动力学建模分析。这项工作具有利用 MoS2 和其他新兴 TMDCs 的优异性能进行实际规模化器件应用的巨大潜力。
