Chemical Vapor Deposition of High‐Optical‐Quality Large‐Area Monolayer Janus Transition Metal Dichalcogenides
Ziyang Gan, Ioannis Paradisanos, Ana Estrada‐Real, Julian Picker, Emad Najafidehaghani, Francis Huw Davies, Christof Neumann, Cédric Robert, Peter R. Wiecha, Kenji Watanabe, Takashi Taniguchi, X. Marie, Johannes Biskupek, Manuel Mundszinger, Robert Leiter, Ute Kaiser, Arkady V. Krasheninnikov, Bernhard Urbaszek, Antony George, Andrey Turchanin
Abstract
Abstract 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 MoSe 2 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.