Twist-angle-dependent Optical Behaviors of Excitons in Twisted Bilayer MoS2 at Low Temperature

Twisted bilayers of two-dimensional materials provide a powerful and attractive platform to control band structure and tailor optical properties since the twist angle B between the bilayer has been shown to be a critical parameter in engineering the moire potential. Here, we demonstrate the B-driven effects on excitons in twisted bilayer MoS2 (tBLMs) by measuring photoluminescence (PL) spectra. The localized state exciton between 1.70 eV and 1.80 eV is observed at 7 K with properties periodically modulated by B. The B is also a crucial factor affecting direct excitons. Furthermore, the phonon around 410 cm(-1) has a B dependence similar to excitons by measuring Raman spectra. The localized stacking patterns, the recombination of excitons, and the phonon-exciton interactions are confirmed in tBLMs. Our work provides the help to investigate the new quantum phenomena of tBLMs by optical methods and provides possibilities to manipulate the emission of excitons in tBLMs.