Scaling behavior of nanoimprint and nanoprinting lithography for producing nanostructures of molybdenum disulfide
Scaling behavior of nanoimprint and nanoprinting lithography for producing nanostructures of molybdenum disulfide
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DOI：
10.1038/micronano.2017.53
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发表时间：
2017-09-11
影响因子：
7.9
通讯作者：
Liang, Xiaogan
中科院分区：
文献类型：
--
作者：
Chen, Mikai;Rokni, Hossein;Liang, Xiaogan
基于新兴的2D层状材料制造均匀的器件结构需要自上而下的光刻技术。基于纳米压痕和纳米压痕原理的机械剥离方法能够产生具有高度均匀特征尺寸的多层过渡金属二卤化物微结构的有序阵列。在这项研究中，我们研究了纳米压痕辅助剪切剥离在制备超薄单层和少层MoS_2结构中的适用性，以及通过这种纳米压痕和基于纳米压痕的工艺所产生的特征尺寸的临界极限。特别是，这项工作表明，给定在体压印上预图案化的MoS2结构的横向特征尺寸，存在一个临界厚度或长宽比值，低于该值，剥离的层状结构表现出主要缺陷。为了剥离高质量、均匀的单层或少层结构，这种结构的特征横向特征尺寸需要在100 nm以下。此外，剥离的临界厚度的MoS_2片在解理表面显示出显著的层间扭曲特征。由这些MoS2薄片制成的场效应晶体管表现出多个(或准模拟可调的)电荷记忆状态。这项工作加深了人们对纳米压痕和纳米压痕工艺在基于层状材料的纳米/微结构制造中的局限性和应用范围的认识，并提供了一种制造多位电荷存储器件的方法。
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 MoS2 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 MoS2 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 high-quality, 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 MoS2 flakes of critical thicknesses exhibit prominent interlayer twisting features on their cleaved surfaces. Field-effect transistors made from these MoS2 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.