An optical spectrum study of interlayer interaction in WS2/WSe2 heterostructure

Atomic-scale two-dimentional transition metal dichalcogenides possess novel electronic and optical properties. Stacking them into van der Waals heterostructures generates new optical properties because of interlayer coupling and charge transfer at the interface, which has important potential applications in photoelectric devices. WS2/WSe2 heterostructure was fabricated successfully by mechanical exfoliation and the interlayer interaction was studied by temperature-dpendent Raman spectra and photoluminescence (PL) spectra. Interlayer phonon mode and exciton were observed from Raman spectra and PL spectra respectively indicating that WS2/WSe2 heterostructure had obvious interaction between layers. Because of type II band alignment at the interface of WS2/WSe2 heterostructure, electrons were transferred from WSe2 to WS2 thus significantly affecting the PL intenstiy of trions and excitons.