| AVS 66th International Symposium & Exhibition | |
| 2D Materials | Tuesday Sessions |
| Session 2D+EM+MI+MN+NS+QS-TuM |
| Session: | Novel Quantum Phenomena |
| Presenter: | Hsun-Jen Chuang, U.S. Naval Research Laboratory |
| Authors: | H.-J. Chuang, U.S. Naval Research Laboratory A.T. Hanbicki, U.S. Naval Research Laboratory M.R. Rosenberger, U.S. Naval Research Laboratory C.S. Hellberg, U.S. Naval Research Laboratory S.V. Sivaram, U.S. Naval Research Laboratory K.M. McCreary, U.S. Naval Research Laboratory I.I. Mazin, U.S. Naval Research Laboratory B.T. Jonker, U.S. Naval Research Laboratory |
| Correspondent: | Click to Email |
An emerging class of heterostructures involves monolayer semiconductors such as many of the transition metal dichalcogenides (TMDs) which can be combined to form van der Waals heterostructures (vdWHs). One unique new optical property of heterostructure is an interlayer exciton (ILE), a spatially indirect, electron-hole pair with the electron in one TMD layer and the hole in the other. Here, we fabricated MoSe2/WSe2 hetero-bilayer encapsulated in h-BN with the alignment angle close to 60 degree between MoSe2 and WSe2. Followed by the state-of-the-art preparation techniques (Nano-squeegee) to ensure the optimal contact between the TMDs. The Strong ILE emission is observed with the emission energy around 1.35 eV at room temperature and resolve this emission into two distinct peaks (ILE1 and ILE2) separated by 24 meV at zero field at 5 K. Furthermore, we demonstrate that the two emission peaks have oppositecircular polarizations with up to +20% for the ILE1 and -40% for ILE2 when excited by circularly polarized light. Ab initio calculations provide an explanation of this unique and potentially useful property and indicate that it is a result of the indirect character of both electronictransitions. These peaks are doubleindirect excitons. i.e.indirect in both real and reciprocal space, split by relativistic effects.
This research was performed while H.-J.C. held an American Society for Engineering Education fellowship and M.R.R and S.V.S held a National Research Council fellowship at NRL. This work was supported by core programs at NRL and the NRL Nanoscience Institute. This work was also supported in part by a grant of computer time from the DoD High Performance Computing Modernization Program at the U.S. Army Research Laboratory Supercomputing Resource Center.