Intermediate State between MoSe2 and Janus MoSeS during Atomic Substitution Process

Hiroo Suzuki; Yijun Liu; Masaaki Misawa; Chiyu Nakano; Yingzhe Wang; Ryo Nakano; Kentaro Ishimura; Kenji Tsuruta; Yasuhiko Hayashi

doi:10.1021/acs.nanolett.3c00972

Intermediate State between MoSe₂ and Janus MoSeS during Atomic Substitution Process

Nano Lett. 2023 May 24;23(10):4533-4540. doi: 10.1021/acs.nanolett.3c00972. Epub 2023 May 8.

Authors

Hiroo Suzuki^{1

2}, Yijun Liu¹, Masaaki Misawa^{1

2}, Chiyu Nakano³, Yingzhe Wang¹, Ryo Nakano¹, Kentaro Ishimura¹, Kenji Tsuruta^{1

2}, Yasuhiko Hayashi^{1

2}

Affiliations

¹ Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
² Faculty of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
³ Advanced Science Research Center, Okayama University, Okayama 700-8530, Japan.

PMID: 37155295
DOI: 10.1021/acs.nanolett.3c00972

Abstract

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 MoSe₂ 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.

Keywords: Density functional theory calculation; Janus TMDCs; Photoluminescence spectroscopy; Plasma process; Raman spectroscopy; Transition metal dichalcogenides (TMDCs).