Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering , Beijing Institute of Technology , Beijing 100081 , P. R. China.
Laser Assisted Nano Engineering Laboratory, Department of Electrical and Computer Engineering , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0511 , United States.
ACS Appl Mater Interfaces. 2019 Oct 23;11(42):39334-39341. doi: 10.1021/acsami.9b13059. Epub 2019 Oct 8.
Molybdenum disulfide (MoS) micro/nanostructures are desirable for tuning electronic properties, developing required functionality, and improving the existing performance of multilayer MoS devices. This work presents a useful method to flexibly microprocess multilayer MoS flakes through femtosecond laser pulse direct writing, which can directly fabricate regular MoS nanoribbon arrays with ribbon widths of 179, 152, 116, 98, and 77 nm, and arbitrarily pattern MoS flakes to form micro/nanostructures such as single nanoribbon, labyrinth array, and cross structure. This method is mask-free and simple and has high flexibility, strong controllability, and high precision. Moreover, numerous oxygen molecules are chemically and physically adsorbed on laser-processed MoS, attributed to roughness defect sites and edges of micro/nanostructures that contain numerous unsaturated edge sites and highly active centers. In addition, electrical tests of the field-effect transistor fabricated from the prepared MoS nanoribbon arrays reveal new interesting features: output and transfer characteristics exhibit a strong rectification (not going through zero and bipolar conduction) of drain-source current, which is supposedly attributed to the parallel structures with many edge defects and p-type chemical doping of oxygen molecules on MoS nanoribbon arrays. This work demonstrates the ability of femtosecond laser pulses to directly induce micro/nanostructures, property changes, and new device properties of two-dimensional materials, which may enable new applications in electronic devices based on MoS such as logic circuits, complementary circuits, chemical sensors, and p-n diodes.
二硫化钼（MoS）微/纳米结构可用于调节电子性能、开发所需的功能以及提高多层 MoS 器件的现有性能。本工作提出了一种通过飞秒激光脉冲直接写入灵活微加工多层 MoS 薄片的有用方法，该方法可以直接制造具有 179、152、116、98 和 77nm 带状宽度的规则 MoS 纳米带阵列，以及任意图案的 MoS 薄片，以形成微/纳米结构，如单纳米带、迷宫阵列和交叉结构。这种方法是无掩模的，简单且具有高度的灵活性、强可控性和高精度。此外，大量的氧分子通过化学和物理吸附在激光处理的 MoS 上，这归因于微/纳米结构的粗糙度缺陷位和边缘含有大量不饱和边缘位和高活性中心。此外，由制备的 MoS 纳米带阵列制成的场效应晶体管的电气测试显示出一些新的有趣特征：漏源电流的输出和传输特性表现出很强的整流（不经过零点和双极传导），这可能归因于具有许多边缘缺陷的平行结构和 MoS 纳米带阵列上氧分子的 p 型化学掺杂。这项工作展示了飞秒激光脉冲直接诱导二维材料的微/纳米结构、性能变化和新器件性能的能力，这可能为基于 MoS 的电子器件开辟新的应用，如逻辑电路、互补电路、化学传感器和 p-n 二极管。
