Pareek Devendra, Gonzalez Marco A, Zohrabian Jannik, Sayed Mohamed H, Steenhoff Volker, Lattyak Colleen, Vehse Martin, Agert Carsten, Parisi Jürgen, Schäfer Sascha, Gütay Levent
Institute of Physics, Carl von Ossietzky University of Oldenburg Oldenburg Germany
DLR Institute of Networked Energy Systems Oldenburg Germany.
RSC Adv. 2018 Dec 21;9(1):107-113. doi: 10.1039/c8ra08626e. eCollection 2018 Dec 19.
In this work a vapor-phase-assisted approach for the synthesis of monolayer MoS is demonstrated, based on the sulfurization of thin MoO precursor films in an HS atmosphere. We discuss the co-existence of various possible growth mechanisms, involving solid-gas and vapor-gas reactions. Different sequences were applied in order to control the growth mechanism and to obtain monolayer films. These variations include the sample temperature and a time delay for the injection of HS into the reaction chamber. The optimized combination allows for tuning the process route towards the potentially more favorable vapor-gas reactions, leading to an improved material distribution on the substrate surface. Raman and photoluminescence (PL) spectroscopy confirm the formation of ultrathin MoS films on SiO/Si substrates with a narrow thickness distribution in the monolayer range on length scales of a few millimeters. Best results are achieved in a temperature range of 950-1000 °C showing improved uniformity in terms of Raman and PL line shapes. The obtained films exhibit a PL yield similar to mechanically exfoliated monolayer flakes, demonstrating the high optical quality of the prepared layers.
在这项工作中，展示了一种气相辅助合成单层MoS的方法，该方法基于在HS气氛中对薄MoO前驱体薄膜进行硫化。我们讨论了各种可能的生长机制的共存，包括固气和气相反应。为了控制生长机制并获得单层薄膜，采用了不同的顺序。这些变化包括样品温度和向反应室注入HS的时间延迟。优化的组合允许调整工艺路线，使其朝着潜在更有利的气相反应发展，从而改善衬底表面上的材料分布。拉曼光谱和光致发光（PL）光谱证实了在SiO/Si衬底上形成了超薄MoS薄膜，在几毫米长度尺度上的单层范围内具有窄的厚度分布。在950-1000°C的温度范围内取得了最佳结果，在拉曼和PL线形方面显示出改善的均匀性。所获得的薄膜表现出与机械剥离的单层薄片相似的PL产率，证明了所制备层的高光学质量。
