Materials properties of out-of-plane heterostructures of MoS2-WSe2 and WS2-MoSe2

Abstract

Based on first-principles calculations, the materials properties (structural, electronic, vibrational, and optical properties) of out-of-plane heterostructures formed from the transition metal dichalcogenides, specifically MoS2-WSe2 and WS2-MoSe2, were investigated. The heterostructures of MoS2-WSe2 and WS2-MoSe2 are found to be direct and indirect band gap semiconductors, respectively. However, a direct band gap in the WS2-MoSe2 heterostructure can be achieved by applying compressive strain. Furthermore, the excitonic peaks in both monolayer and bilayer heterostructures are calculated to understand the optical behavior of these systems. The suppression of the optical spectrum with respect to the corresponding monolayers is due to interlayer charge transfer. The stability of the systems under study is confirmed by performing phonon spectrum calculations.