Abstract
Quantum confinement effect and reduced dielectric screening in two-dimensional(2D)dramatically enhance the electron-hole interactions.In this work,we use many-body perturbation theory and Bethe-Salpeter equation(BSE)to investigate the electronic and excitonic optical properties of monolayer SnP2S6.Our findings reveal that the excitonic effect dominates the optical absorption spectra in the visible light range,and the lowest-energy exciton X0 in monolayer SnP2S6 is optically bright with the binding energy of 0.87 eV and the radiative lifetime of～10-11 s,which is highly ad-vantageous to the photo-luminescence.Most importantly,the absence of optically forbidden states below the bright states X0 would give rise to a high quantum efficiency of 2D SnP2S6.We also find that applied biaxial strain can further shorten the radiative lifetime of the bright states.These results imply that 2D SnP2S6 is a promising candidate for the optoelectronic devices.
基金项目
Project support by the National Natural Science Foundation of China(12064032)
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