title: Spectroscopic signatures for interlayer coupling in MoS2-WSe2 van der Waals stacking.
abstract: Stacking of MoS2 and WSe2 monolayers is conducted by transferring triangular MoS2 monolayers on top of WSe2 monolayers, all grown by chemical vapor deposition (CVD). Raman spectroscopy and photoluminescence (PL) studies reveal that these mechanically stacked monolayers are not closely coupled, but after a thermal treatment at 300 °C, it is possible to produce van der Waals solids consisting of two interacting transition metal dichalcogenide (TMD) monolayers. The layer-number sensitive Raman out-of-plane mode A(2)1g for WSe2 (309 cm(-1)) is found sensitive to the coupling between two TMD monolayers. The presence of interlayer excitonic emissions and the changes in other intrinsic Raman modes such as E″ for MoS2 at 286 cm(-1) and A(2)1g for MoS2 at around 463 cm(-1) confirm the enhancement of the interlayer coupling.
authors.affiliation: Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Chiu
authors.forename: Ming-Yang
authors.initials: MY
authors.lastname: Li
authors.forename: Wengjing
authors.initials: W
authors.lastname: Zhang
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Hsu
authors.forename: Wen-Hao
authors.initials: WH
authors.lastname: Chang
authors.forename: Mauricio
authors.initials: M
authors.lastname: Terrones
authors.forename: Humberto
authors.initials: H
authors.lastname: Terrones
authors.forename: Lain-Jong
authors.initials: LJ
authors.lastname: Li
keywords: heterojunction; interlayer coupling; molybdenum disulfide; transition metal dichalcogenides; tungsten diselenides; van der Wall stacking