Excitonic Complexes in n-Doped WS2 Monolayer

We investigate the origin of emission lines apparent in the low-temperature photoluminescence spectra of n-doped WS2 monolayer embedded in hexagonal BN layers using external magnetic fields and first-principles calculations. Apart from the neutral A exciton line, all observed emission lines are related to the negatively charged excitons. Consequently, we identify emissions due to both the bright singlet and triplet) and dark (spin- and momentum-forbidden) negative trions as well as the phonon replicas of the latter optically inactive complexes. The semidark trions and negative biexcitons are distinguished. On the basis of their experimentally extracted and theoretically calculated g-factors, we identify three distinct families of emissions due to exciton complexes in WS,: bright, intravalley, and intervalley dark. The g-factors of the spin-split subbands in both the conduction and valence bands are also determined.

Automated summary

In this study, the origin of emission lines in the low-temperature photoluminescence spectra of n-doped WS2 monolayer embedded in hexagonal BN layers was investigated using external magnetic fields and first-principles calculations. Different families of emissions due to exciton complexes in WS2 were identified based on experimentally extracted and theoretically calculated g-factors, as well as the determination of g-factors of the spin-split subbands in both the conduction and valence bands.