Spectroscopic signatures for interlayer coupling in MoS2-WSe2 van der Waals stacking

Ming-Hui Chiu; Ming-Yang Li; Wengjing Zhang; Wei-Ting Hsu; Wen-Hao Chang; Mauricio Terrones; Humberto Terrones; Lain-Jong Li

doi:10.1021/nn504229z

Spectroscopic signatures for interlayer coupling in MoS2-WSe2 van der Waals stacking

ACS Nano. 2014 Sep 23;8(9):9649-56. doi: 10.1021/nn504229z. Epub 2014 Sep 10.

Authors

Ming-Hui Chiu¹, Ming-Yang Li, Wengjing Zhang, Wei-Ting Hsu, Wen-Hao Chang, Mauricio Terrones, Humberto Terrones, Lain-Jong Li

Affiliation

¹ Physical Sciences and Engineering, King Abdullah University of Science and Technology , Thuwal 23955-6900, Kingdom of Saudi Arabia.

PMID: 25196077
DOI: 10.1021/nn504229z

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.

Keywords: heterojunction; interlayer coupling; molybdenum disulfide; transition metal dichalcogenides; tungsten diselenides; van der Wall stacking.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.