Two-dimensional transition metal dichalcogenides (2D TMDs) is one of the promising materials for future electronics since they have, not only superior characteristics, but also a versatility that conventional materials do not have with a few nanometer thickness. One of the prerequisites for applying these materials to device fabrication is to deposit an ultrathin film below 10 nm with excellent uniformity. However, TMD has quite a different surface chemistry and is fragile to external conditions compared to conventional materials. Thus, thin film deposition on 2D TMD with excellent uniformity using conventional deposition techniques is quite challenging. Currently, the most adequate deposition technique for sub-10 nm-thick film growth is atomic layer deposition (ALD). A thin film is formed on the surface by the reaction between chemical and surface species based on the self-limiting growth manner. Owing to its unique and superior growth characteristics, such as excellent uniformity and conformality, ALD is an essential deposition technique for nanoscale device fabrication. However, since 2D TMD has a lack of reaction sites on the surface, various studies have reported that ALD on 2D TMDs surfaces without any treatment showed an island growth mode or formation of clusters rather than continuous films. For this reason, recent studies have been focused on the deposition of an ultrathin film on 2D TMDs with excellent uniformity. For a decade, there have been various approaches to obtain uniform films on 2D TMDs using ALD. Among them, the authors focus on the most frequently researched methods and adsorption control of chemical species by modifying the process parameters or functionalization of new chemical species that can assist adsorption on the chemically inert 2D TMD surface. In this review, the overall research progress of ALD on 2D TMD will be discussed which would, in turn, open up new horizons in future nanoelectronics fabrication using 2D TMDs.

中文翻译：

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在二维过渡金属二卤化物上均匀薄膜的原子层沉积

二维过渡金属二硫化碳（2D TMD）是未来电子产品的有前途的材料之一，因为它们不仅具有优越的性能，而且具有多种常规材料所不具备的几纳米厚度。将这些材料应用于器件制造的前提条件之一是淀积 10nm以下的超薄薄膜，并具有出色的均匀性。但是，与传统材料相比，TMD具有完全不同的表面化学性质，并且易受外部条件的影响。因此，使用常规沉积技术在2D TMD上以优异的均匀性进行薄膜沉积是非常具有挑战性的。目前，最适合亚10级的沉积技术 纳米厚的膜生长是原子层沉积（ALD）。基于自限生长方式，通过化学物质与表面物质之间的反应在表面形成薄膜。由于其独特和卓越的生长特性，例如出色的均匀性和保形性，ALD是纳米级器件制造中必不可少的沉积技术。然而，由于二维TMD在表面上没有反应位点，因此各种研究已经报道，未经任何处理的二维TMDs表面上的ALD显示出岛状生长模式或簇的形成而不是连续的膜。因此，最近的研究集中于在2D TMD上以极好的均匀性沉积超薄膜。十年来，已经有了使用ALD在2D TMD上获得均匀薄膜的各种方法。其中，作者着眼于最常研究的方法和对化学物质的吸附控制，方法是修改工艺参数或对新化学物质进行功能化，以帮助吸附在化学惰性2D TMD表面上。在这篇综述中，将讨论ALD在2D TMD上的整体研究进展，这反过来将为使用2D TMD的未来纳米电子制造开辟新的前景。