Forming pits on molybdenum disulfide (MoS₂) monolayers is desirable for (opto)electrical, catalytic, and biological applications. Thermal oxidation is a potentially scalable method to generate pits on monolayer MoS₂, and pits are assumed to preferentially form around undercoordinated sites, such as sulfur vacancies. However, studies on thermal oxidation of MoS₂ monolayers have not considered the effect of adventitious carbon (C) that is ubiquitous and interacts with oxygen at elevated temperatures. Herein, the effect of adventitious C on the pit formation on MoS₂ monolayers during thermal oxidation is studied. The in situ environmental transmission electron microscopy measurements herein show that pit formation is preferentially initiated at the interface between adventitious C nanoparticles and MoS₂, rather than only sulfur vacancies. Density functional theory (DFT) calculations reveal that the C/MoS₂ interface favors the sequential adsorption of oxygen atoms with facile kinetics. These results illustrate the important role of adventitious C on pit formation on monolayer MoS₂.

中文翻译：

---

不定碳对单层MoS2基坑形成的影响。

对于（光电）电，催化和生物应用，在二硫化钼（MoS ₂）单层上形成凹坑是理想的。热氧化是在单层MoS ₂上生成凹坑的潜在可扩展方法，并且假定凹坑优先形成于未配位的位点周围，例如硫空位。但是，有关MoS ₂单层热氧化的研究尚未考虑不定碳（C）的影响，该碳在高温下普遍存在并与氧相互作用。此处，不定碳对MoS ₂上凹坑形成的影响研究了热氧化过程中的单分子层。本文的原位环境透射电子显微镜测量结果表明，凹坑的形成优先在不定形C纳米颗粒和MoS ₂之间的界面处开始，而不仅仅是硫空位。密度泛函理论（DFT）计算表明，C / MoS ₂界面有利于以容易的动力学顺序吸附氧原子。这些结果说明了不定形C对单层MoS ₂上的凹坑形成的重要作用。