Modulating interlayer and intralayer excitons in WS2/WSe2 van der Waals heterostructures

Abstract

Intralayer and interlayer excitons are fundamental quasiparticles that can appear simultaneously in transition metal dichalcogenide van der Waals heterostructures. The understanding and modulation of the interaction of interlayer and intralayer excitons are of great importance for both fundamental studies and device applications. Here, we demonstrate the modulation of photoluminescence (PL) emissions of interlayer and intralayer excitons in WSe2/WS2 heterostructures using different stacking configurations in a single sample, including with and without hexagonal boron nitride (hBN) encapsulation and different hBN spacing layers. By temperature dependent PL spectroscopy, we observed the suppression of interlayer exciton formation and exciton complexes at high temperatures due to enhanced phonon scattering. We also verify the formation of these states via power dependent spectroscopy. Our electric field and doping dependent PL studies reveal that the interlayer exciton peaks shift linearly with the applied gate voltage and the intralayer excitons of WSe2 (WS2) are dominant at high n-doping (p-doping). Our results contribute to the understanding of the interplay between interlayer and intralayer excitons in WSe2/WS2 heterostructures and could promote the related exitonic device applications.