Revealing localized excitons in WSe2/β-Ga2O3


Camila Cavalini, Cesar Rabahi, Caique S. de Brito, Eunji Lee, José R. Toledo, Felipe F. Cazetta, Raphael B. Fernandes de Oliveira, Marcelo B. Andrade, Mohamed Henini, Yuhao Zhang, Jeongyong Kim, Ingrid D. Barcelos, and Yara Galvão Gobato. 2024. “Revealing localized excitons in WSe2/β-Ga2O3.” Applied Physics Letters, 124, 14, Pp. 142104.


We have investigated the optical and magneto-optical properties of monolayer (ML) WSe2 on flakes of β-Ga2O3 under high magnetic fields. Remarkably, sharp emission peaks were observed and associated with localized excitons related to point defects. A detailed study of low-temperature photoluminescence (PL) and magneto-PL under high perpendicular magnetic field up to 9 T was carried out. Several sharp emission peaks have shown valley g-factors values close to −4, which is an unusual result for localized excitons in WSe2. Furthermore, some PL peaks have shown higher g-factor values of ≈−7 and ≈−12, which were associated with the hybridization of strain localized dark excitons and defects. The reported results suggest that β-Ga2O3 is, indeed, a promising dielectric substrate for ML WSe2 and also to explore fundamental physics in view of possible applications in quantum information technology.