Tunable interlayer excitons in two-dimensional SiC/MoSSe van der Waals heterostructures

In two-dimensional (2D) van der Waals heterostructures, the excitonic effects are significant enhanced due to the reduction of screening. Accurate description of light-matter interaction of 2D heterostructures is essential to understand their excitonic optical response and radiative lifetime. In this paper, the quasiparticle band structures and excitonic optical properties of SiC/MoSSe heterostructures are investigated by the GW + Bethe-Salpeter equation (GW + BSE) approach. Here the four stable structures 1-AA, 1-A'B, 2-AA and 2-A'B of SiC/MoSSe heterostructures are all type-II band alignment semiconductors, which are favorable for producing interlayer excitons. We find that low energy interlayer excitons of all the four structures posess high binding energies, and the optical dipole oscillator strength and radiative lifetimes can be modulated by several orders of magnitude as a result of the different intrinsic dipole moments of MoSSe. More interestingly, we also find that in 1-A'B and 2-A'B, the lowest-energy exciton is bright interlayer exciton with a strong absorption peak. The detailed analysis of the binding energies, transition contributions and exciton lifetimes of these interlayer excitons will be helpful for SiC/MoSSe heterostructures applications in the optoelectronics.