Paidi Hemanth Kumar, Mudunuri Rishitha, Babu Deepu J
Department of Materials Science and Metallurgical Engineering, Indian Institute of Technology Hyderabad, Sangareddy, Telangana 502285, India.
Affiliated Faculty, Department of Climate Change, Indian Institute of Technology Hyderabad, Sangareddy, Telangana 502285, India.
Langmuir. 2024 Dec 3;40(48):25648-25656. doi: 10.1021/acs.langmuir.4c03567. Epub 2024 Nov 20.
Transition-metal dichalcogenides (TMDs), in particular MoS, have garnered a lot of interest due to their unique properties and potential applications. Chemical vapor deposition (CVD) is generally used to synthesize 2D films of MoS. The synthesis of MoS is highly sensitive to growth parameters such as temperature, pressure, flow rate, precursor ratio, etc. Though there are several accounts of MoS synthesis via atmospheric-pressure CVD (APCVD) and low-pressure CVD (LPCVD), there is a lack of a comparative analysis between the two methods, which could potentially offer a better perspective on the growth of MoS. This work systematically investigates the growth of MoS under APCVD and LPCVD conditions. The APCVD growth of MoS is found to be diffusion-limited, leading to the characteristic triangular morphology, while the LPCVD growth is reaction-limited. The enhanced mass flux in LPCVD, even at much lower temperatures (Δ ≥ 200 °C), increases the nucleation density, resulting in a continuous polycrystalline film covering the entire substrate. This comparative study provides a better insight into understanding the crystallization and growth of MoS, which can also be extended to other TMDs.
过渡金属二硫属化物（TMDs），特别是二硫化钼（MoS₂），因其独特的性质和潜在应用而备受关注。化学气相沉积（CVD）通常用于合成二硫化钼的二维薄膜。二硫化钼的合成对诸如温度、压力、流速、前驱体比例等生长参数高度敏感。尽管有几篇关于通过大气压化学气相沉积（APCVD）和低压化学气相沉积（LPCVD）合成二硫化钼的报道，但缺乏对这两种方法的比较分析，而这种分析可能会为二硫化钼的生长提供更好的视角。这项工作系统地研究了在APCVD和LPCVD条件下二硫化钼的生长情况。发现二硫化钼在APCVD下的生长受扩散限制，导致其具有特征性的三角形形态，而在LPCVD下的生长受反应限制。即使在低得多的温度下（Δ≥200°C），LPCVD中增强的质量通量也会增加成核密度，从而形成覆盖整个衬底的连续多晶薄膜。这项比较研究为理解二硫化钼的结晶和生长提供了更好的见解，这也可以扩展到其他TMDs。
