Chemical Vapor Deposition of High-Optical-Quality Large-Area Monolayer Janus Transition Metal Dichalcogenides

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Advanced Materials, Volume 34, issue 38
One-pot chemical vapor deposition (CVD) growth of large-area Janus SeMoS monolayers is reported, with the asymmetric top (Se) and bottom (S) chalcogen atomic planes with respect to the central transition metal (Mo) atoms. The formation of these 2D semiconductor monolayers takes place upon the thermodynamic-equilibrium-driven exchange of the bottom Se atoms of the initially grown MoSe2 single crystals on gold foils with S atoms. The growth process is characterized by complementary experimental techniques including Raman and X-ray photoelectron spectroscopy, transmission electron microscopy, and the growth mechanisms are rationalized by first principle calculations. The remarkably high optical quality of the synthesized Janus monolayers is demonstrated by optical and magneto-optical measurements which reveal the strong exciton–phonon coupling and enable an exciton g-factor of −3.3.
Funding Information: The Jena group received financial support of the Deutsche Forschungsgemeinschaft (DFG) through a research infrastructure grant INST 275/257‐1 FUGG (313713174), CRC 1375 NOA (Project B2, 398816777) and SPP2244 (Project TU149/13‐1, 443361515). This project has also received funding from the joint European Union's Horizon 2020 and DFG research and innovation programme FLAG‐ERA under grant TU149/9‐1 (397373225). Ulm and Jena acknowledge financial support of the joint DFG project within grant 464283495. The authors from Toulouse received funding from the Institute for Quantum Technologies Occitanie, ANR IXTASE and the Institut Universitaire de France. Growth of hexagonal boron nitride crystals was supported by the Elemental Strategy Initiative conducted by the MEXT, Japan, Grant Number JPMXP0112101001, JSPS KAKENHI Grant Number JP20H00354, and the CREST (JPMJCR15F3), JST. A.V.K. further thanks DFG for the support through Project KR 4866/8‐1 and the Collaborative Research Center “Chemistry of Synthetic 2D Materials” SFB‐1415‐417590517. The authors also thank the HZDR Computing Center, HLRS, Stuttgart, Germany, and TU Dresden Cluster “Taurus” for generous grants of CPU time. The authors thank Stephanie Höppener and Ulrich S. Schubert for enabling the Raman spectroscopy and microscopy studies at the Jena Center for Soft Matter (JCSM). Publisher Copyright: © 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.
2D materials, exciton–phonon coupling, high optical quality, Janus transition metal dichalcogenides, monolayers
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Gan , Z , Paradisanos , I , Estrada-Real , A , Picker , J , Najafidehaghani , E , Davies , F , Neumann , C , Robert , C , Wiecha , P , Watanabe , K , Taniguchi , T , Marie , X , Biskupek , J , Mundszinger , M , Leiter , R , Kaiser , U , Krasheninnikov , A V , Urbaszek , B , George , A & Turchanin , A 2022 , ' Chemical Vapor Deposition of High-Optical-Quality Large-Area Monolayer Janus Transition Metal Dichalcogenides ' , Advanced Materials , vol. 34 , no. 38 , 2205226 .