Spontaneous n-Doping in Growing Monolayer MoS2 by Alkali Metal Compound-Promoted CVD
Spontaneous n-Doping in Growing Monolayer MoS2 by Alkali Metal Compound-Promoted CVD
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通过碱金属化合物促进的 CVD 生长单层 MoS2 中的自发 n 掺杂
DOI：
10.1021/acsami.1c17409
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Bo Gao
中科院分区：
文献类型：
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作者：
Peng Wang;Jiafan Qu;Yadong Wei;Hongyan Shi;Jian Wang;Xiudong Sun;Weiqi Li;Wenjun Liu;Bo Gao
由于其令人着迷的物理特性和光电性能，单层二硫化钼已成为未来半导体器件最有前途的候选材料之一。近年来，利用碱金属化合物作为CVD生长的促进剂已被证明是一种生长单层mos2和其他具有大结构域的2D tmd的简便策略。在这项工作中，我们系统地研究了碱金属化合物的残留物，以及在碱金属化合物促进CVD生长的单层mos2中自发的n掺杂效应。当使用NaOH和其他碱金属化合物作为启动子时，发现A1gmode的拉曼峰随着宽度变宽而红移，而a峰的PL强度随着红移而降低，这归因于生长过程中自发的n掺杂效应。此外，使用不同数量的NaOH启动子的生长表明n掺杂水平可以通过启动子的数量来控制。x射线光电子能谱（XPS）和飞行时间二次离子质谱（TOF-SIMS）结果表明，在单层二硫化钼表面存在Na-O团簇形式的阳离子残留，转移实验也证实了这一点。NaOH处理实验和密度泛函理论（DFT）计算表明，氢氧化钠簇可以由Na-O簇和水蒸气的组合转化为氢氧化钠簇，可以在单层MoS2上产生n掺杂效应。这项研究提供了一种简单的途径，可以控制生长具有所需掺杂水平的单层二维材料，而无需进一步处理。
Monolayer MoS2has emerged as one of the most promising candidate materials for future semiconductor devices because of its fascinating physical properties and optoelectronic performance. Recently, the utilization of alkali metal compounds as promoters in CVD growth has been demonstrated to be a facile strategy for growing monolayer MoS2and other 2D TMDs with large domain sizes. In this work, we systematically investigated the residues derived from alkali metal compounds and the spontaneous n-doping effect on monolayer MoS2in alkali metal compound-promoted CVD growth. When using NaOH and other alkali metal compounds as promoters, it is found that the Raman peak of the A1gmode red shifted with a broadening width and the PL intensity of the A peak decreased with a red shift, which was attributed to the spontaneous n-doping effect during growth. Moreover, the growth using varying amounts of NaOH promoter suggests that the n-doping level could be controlled by the amount of promoter. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) showed the existence of cation-derived residues in the form of a Na–O cluster physiosorbed on top of monolayer MoS2, which was also confirmed by the transfer experiment. The NaOH treatment experiment and density functional theory (DFT) calculations demonstrate that sodium hydroxide clusters, which could be converted from a combination of Na–O clusters and water vapor, could produce an n-doping effect on monolayer MoS2. This study provides a facile route to controllably grow monolayer 2D materials with a desired doping level without further treatment.