Real-space exciton distribution in strained-siligraphene g-SiC7

Abstract

Siligraphene belonging to the family of two-dimensional (2D) materials has great potential in optoelectronics due to its considerable excitonic effects. In this study, the strain effects on the electronic structure and the real-space exciton wave functions of g-SiC7 are investigated using the first-principles calculations based on the ab initio many-body perturbation theory. Alongside the increase (decrease) of the bandgap with compressive (tensile) strain, our results show that the exciton in the siligraphene monolayer under in-plane biaxial compressive strains is much more localized than that in the case of tensile one, leading to the higher and lower exciton binding energies, respectively. Moreover, the π↦π and π↦σ exciton state transition emerges when applying the compressive and tensile strains, respectively. Overall, our study reveals that a desirable way to dissociate the electron-hole coupling and to reduce the electron-hole recombination process is applying “in-plane biaxial tensile strain,” making g-SiC7 an excellent potential functional 2D semiconductor in optoelectronics.