Stanev Teodor K, Liu Pufan, Zeng Hongfei, Lenferink Erik J, Murthy Akshay A, Speiser Nathaniel, Watanabe Kenji, Taniguchi Takashi, Dravid Vinayak P, Stern Nathaniel P
Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, United States.
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.
ACS Appl Mater Interfaces. 2022 May 25;14(20):23775-23784. doi: 10.1021/acsami.2c03652. Epub 2022 May 11.
Direct top-down nanopatterning of semiconductors is a powerful tool for engineering properties of optoelectronic devices. Translating this approach to two-dimensional semiconductors such as monolayer transition metal dichalcogenides (TMDs) is challenging because of both the small scales required for confinement and the degradation of electronic and optical properties caused by high-energy and high-dose electron radiation used for high-resolution top-down direct electron beam patterning. We show that encapsulating a TMD monolayer with hexagonal boron nitride preserves the narrow exciton linewidths and emission intensity typical in such heterostructures after electron beam lithography, allowing direct patterning of functional optical monolayer nanostructures on scales of a few tens of nanometers. We leverage this fabrication method to study size-dependent effects on nanodot arrays of MoS and MoSe as well as laterally confined electrical transport devices, demonstrating the potential of top-down lithography for nanoscale TMD optoelectronics.
半导体的直接自上而下纳米图案化是用于设计光电器件特性的强大工具。将这种方法应用于二维半导体，如单层过渡金属二硫属化物（TMD）具有挑战性，这是因为限制所需的尺度小，以及用于高分辨率自上而下直接电子束图案化的高能和高剂量电子辐射会导致电子和光学特性退化。我们表明，用六方氮化硼封装TMD单层在电子束光刻后保留了此类异质结构中典型的窄激子线宽和发射强度，从而能够在几十纳米尺度上直接图案化功能性光学单层纳米结构。我们利用这种制造方法来研究对MoS和MoSe纳米点阵列以及横向受限电输运器件的尺寸依赖性效应，证明了自上而下光刻在纳米级TMD光电子学中的潜力。
