Wan Xi, Chen EnZi, Yao Jie, Gao Mingliang, Miao Xin, Wang Shuai, Gu Yanyun, Xiao Shaoqing, Zhan Runze, Chen Kun, Chen Zefeng, Zeng Xiaoliang, Gu Xiaofeng, Xu Jianbin
Engineering Research Center of IoT Technology Applications (Ministry of Education), Department of Electronic Engineering, Jiangnan University, Wuxi 214122, China.
State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology and Guangdong Province Key Laboratory of Display Material, Sun Yat-sen University, Guangzhou 510275, China.
ACS Nano. 2021 Dec 28;15(12):20319-20331. doi: 10.1021/acsnano.1c08531. Epub 2021 Dec 6.
Janus transition-metal dichalcogenides (TMDCs) are emerging as special 2D materials with different chalcogen atoms covalently bonded on each side of the unit cell, resulting in interesting properties. To date, several synthetic strategies have been developed to realize Janus TMDCs, which first involves stripping the top-layer S of MoS with H atoms. However, there has been little discussion on the intermediate Janus MoSH. It is critical to find the appropriate plasma treatment time to avoid sample damage. A thorough understanding of the formation and properties of MoSH is highly desirable. In this work, a controlled H-plasma treatment has been developed to gradually synthesize a Janus MoSH monolayer, which was confirmed by the TOF-SIMS analysis as well as the subsequent fabrication of MoSSe. The electronic properties of MoSH, including the high intrinsic carrier concentration (∼2 × 10 cm) and the Fermi level (∼ - 4.11 eV), have been systematically investigated by the combination of FET device study, KPFM, and DFT calculations. The results demonstrate a method for the creation of Janus MoSH and present the essential electronic parameters which have great significance for device applications. Furthermore, owing to the metallicity, 2D Janus MoSH might be a potential platform to observe the SPR behavior in the mid-infrared region.
Janus过渡金属二硫属化物（TMDCs）作为一种特殊的二维材料正在兴起，其晶胞的每一侧都有不同的硫属原子通过共价键结合，从而产生有趣的性质。迄今为止，已经开发了几种合成策略来制备Janus TMDCs，首先涉及用氢原子剥离MoS₂的顶层硫原子。然而，对于中间产物Janus MoSH的讨论却很少。找到合适的等离子体处理时间以避免样品受损至关重要。深入了解MoSH的形成和性质是非常必要的。在这项工作中，我们开发了一种可控的氢等离子体处理方法来逐步合成Janus MoSH单层，这通过飞行时间二次离子质谱（TOF-SIMS）分析以及随后制备的MoSSe得到了证实。通过场效应晶体管（FET）器件研究、开尔文探针力显微镜（KPFM）和密度泛函理论（DFT）计算相结合的方法，系统地研究了MoSH的电子性质，包括高本征载流子浓度（约2×10¹³ cm⁻²）和费米能级（约 - 4.11 eV）。结果展示了一种制备Janus MoSH的方法，并给出了对器件应用具有重要意义的基本电子参数。此外，由于其金属性，二维Janus MoSH可能是观察中红外区域表面等离子体共振（SPR）行为的潜在平台。
