Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
Faculty of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
Nano Lett. 2023 May 24;23(10):4533-4540. doi: 10.1021/acs.nanolett.3c00972. Epub 2023 May 8.
Janus transition metal dichalcogenides (TMDCs), with dissimilar chalcogen atoms on each side of TMDCs, have garnered considerable research attention because of the out-of-plane intrinsic polarization in monolayer TMDCs. Although a plasma process has been proposed for synthesizing Janus TMDCs based on the atomic substitution of surface atoms at room temperature, the formation dynamics and intermediate electronic states have not been completely examined. In this study, we investigated the intermediate state between MoSe and Janus MoSeS during plasma processing. Atomic composition analysis and atomic-scale structural observations revealed the intermediate partially substituted Janus (PSJ) structure. Combined with theoretical calculations, we successfully clarified the characteristic Raman modes in the intermediate PSJ structure. The PL exhibited discontinuous transitions that could not be explained by the theoretical calculations. These findings will contribute toward understanding the formation process and electronic-state modulation of Janus TMDCs.
Janus 过渡金属二卤化物（TMDCs），由于单层 TMDCs 中的面外本征极化，在 TMDCs 的每一侧具有不同的卤族原子，引起了相当多的研究关注。尽管已经提出了一种等离子体工艺，用于在室温下通过表面原子的原子取代来合成 Janus TMDCs，但形成动力学和中间电子态尚未完全检查。在这项研究中，我们研究了等离子体处理过程中 MoSe 和 Janus MoSeS 之间的中间状态。原子组成分析和原子尺度结构观察揭示了中间部分取代的 Janus（PSJ）结构。结合理论计算，我们成功地阐明了中间 PSJ 结构中的特征拉曼模式。PL 表现出不连续的跃迁，这不能用理论计算来解释。这些发现将有助于理解 Janus TMDCs 的形成过程和电子态调制。
