Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs), in particular molybdenum disulfide (MoS₂), have recently attracted huge interest due to their proper bandgap, high mobility at 2D limit, and easy-to-integrate planar structure, which are very promising for extending Moore’s law in postsilicon electronics technology. Great effort has been devoted toward such a goal since the demonstration of protype MoS₂ devices with high room-temperature on/off current ratios, ultralow standby power consumption, and atomic level scaling capacity down to sub-1-nm technology node. However, there are still several key challenges that need to be addressed prior to the real application of MoS₂-based electronics technology. The controllable growth of wafer-scale single-crystal MoS₂ on industry-compatible insulating substrates is the prerequisite of application while the currently synthesized MoS₂ films mostly are polycrystalline with limited sizes of single-crystal domains and may involve metal substrates. The precise layer-control is also very important for MoS₂ growth since its electronic properties are layer-dependent, whereas the layer-by-layer growth of multilayer MoS₂ dominated by the van der Waals (vdW) epitaxy leads to poor thickness uniformity and noncontinuously distributed domains. High density up to 10¹³ cm^–2 of sulfur vacancies (SVs) in grown MoS₂ can cause unfavorable carrier scatting and electronic properties variations and will inevitably disturb the device performance. The dangling-bond-free surface of MoS₂ gives rise to an inherent vdW gap at metal–semiconductor (M–S) contact, which leads to high electrical resistance and poor current-delivery capability at the contact interface and thereby substantially limits the performances of MoS₂ devices.

中文翻译：

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二维二硫化钼的可控生长和欧姆接触机制：来自原子模拟的见解


二维 （2D） 半导体过渡金属二硫化物 （TMD），特别是二硫化钼 （MoS₂），由于其适当的带隙、二维极限下的高迁移率和易于集成的平面结构，最近引起了极大的兴趣，这对于在后硅电子技术中的摩尔定律的扩展非常有希望。自从展示具有高室温开/关电流比、超低待机功耗和原子级缩放能力低至 1 纳米技术节点的 proType MoS₂ 器件以来，人们为实现这一目标付出了巨大的努力。然而，在真正应用基于 MoS₂ 的电子技术之前，仍有几个关键挑战需要解决。晶圆级单晶 MoS₂ 在工业兼容的绝缘衬底上的可控生长是应用的先决条件，而目前合成的 MoS₂ 薄膜大多是多晶，单晶畴尺寸有限，可能涉及金属衬底。精确的层控制对于 MoS₂ 的生长也非常重要，因为它的电子特性是分层依赖性的，而以范德华 （vdW） 外延为主的多层 MoS₂ 的逐层生长导致厚度均匀性差和非连续分布畴。生长的 MoS₂ 中高达^{10 13} cm^–2 的硫空位 （SV） 密度高，会导致不利的载流子脱落和电子特性变化，并且不可避免地会干扰器件性能。 MoS₂ 的无悬铆接表面在金属-半导体 （M-S） 接触处产生固有的 vdW 间隙，这会导致接触界面处的高电阻和较差的电流传输能力，从而大大限制了 MoS₂ 器件的性能。