Unraveling biexciton and excitonic excited states from defect bound states in monolayer MoS2

Controlling neutral and charged excitons in MoS2 with defects

“…The formation energy of the S divacancy in the Mo-rich/S-poor limit is calculated to be about 2.4 eV, indicating only a slight binding energy between S vacancies. Our calculations predict that both 0/À1 charge transition levels (CTLs) fall within the band gap and are about 1.55-1.65 eV above the valence band minimum (VBM) in monolayer MoS 2 , again in good agreement with other computational studies [4,24,39,41]. The CTLs indicate the presence of (deep acceptor) defect states in the gap which could trap excitons.…”

“…These peaks were not observed in samples irradiated to lower fluences and are believed to arise from the valley excitons migrating to defects such as sulfur vacancies, which are formed in higher concentrations under higher irradiation fluences. Excitons have been known to migrate to defect bound states in monolayer MoS 2 , and the PL peaks (at 1.70 and 1.82 eV) have been previously verified to be reflective of a defect bound state [41,42,43]. With DFT predicting that V s and V s2 are the most favorable defect types that form in MoS 2 , it is likely that the observed PL peaks are associated with these defects.…”

Electron-phonon interactions and two-phonon modes associated with charge density wave in single crystalline1T−VSe2

“…Layered transition metal dichalcogenides (TMDCs) provide a rich platform for research with their wide range of physical properties varying from metallic, semiconducting, superconducting, and magnetism to having exotic optical properties [10][11][12]. Most 2D materials exist in two stable crystal structures such as 2H (trigonal prismatic) and 1T (octahedron), where the physical properties depend on the symmetry of the phases [13].…”

Breast cancer biomarker detection through the photoluminescence of epitaxial monolayer MoS2 flakes

“…6c,d). Hence, the reasons for the observed behavior are not clear and, despite the recent progress 36,37,46 , the current reports does not allow determining a unique origin for that. More research is needed to establish the exact energies of the excitons and multiexcitons, and the specific effect of defects on the optical properties.…”

“…These defects are known to have a relevant impact on the binding energies of the excitons 16 . Some of these defects have been identified in non-resonant PL studies at low temperatures 36 . Indeed, MoS 2 monolayer seems to exhibit at least six optical transitions at 4 K, three of them ascribed to defects.…”