Interlayer excitons in WSO/MoSi2N4 heterostructures

The intrinsic electric field of Janus layer has an important impact on interlayer excitons of heterostructures constructed by Janus components. In this study, we employ the GW-BSE method to investigate the influence of the intrinsic electric field on interlayer excitons in WSO/MoSi2N4 heterostructures with different stacking configurations. Our findings reveal that reverse the Janus WSO layer strongly alters the electronic structures while keeping the type-Ⅱ band alignment feature. Both structures demonstrate tightly bound bright interlayer excitons. We also observe that the lowest energy interlayer bright exciton (IXB) in 1-WSO has a higher percentage of allowed transitions compared to 2-WSO, due to the multi-band transition characteristic of the participating states. And thus the intrinsic electric field facilitates the transition of IXB in 1-WSO. Consequently, the radiative lifetime of the IXB is extremely short, around 10−10 s at 300 K. Our exploration underscores the significance of the intrinsic electric field in determining the lifetime of IXs.