Abstract
We report charged exciton (trion) formation dynamics in doped monolayer transition metal dichalcogenides, specifically molybdenum diselenide (MoSe2), using resonant two-color pump-probe spectroscopy. When resonantly pumping the exciton transition, trions are generated on a picosecond time scale through exciton-electron interaction. As the pump energy is tuned from the high energy to low energy side of the inhomogeneously broadened exciton resonance, the trion formation time increases by ∼50%. This feature can be explained by the existence of both localized and delocalized excitons in a disordered potential and suggests the existence of an exciton mobility edge in transition metal dichalcogenides.
| Original language | English |
|---|---|
| Article number | 041401 |
| Journal | Physical Review B |
| Volume | 93 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 5 2016 |
Funding
Army Research Office http://dx.doi.org/10.13039/100000183 ARO http://sws.geonames.org/6252001/ http://sws.geonames.org/4482348/ W911NF-15-1-0088 Air Force Office of Scientific Research http://dx.doi.org/10.13039/100000181 AFOSR http://sws.geonames.org/6252001/ http://sws.geonames.org/6254928/ FA9550-10-1-0022 National Science Foundation http://dx.doi.org/10.13039/100000001NSF http://sws.geonames.org/6252001/ http://sws.geonames.org/6254928/ DMR-1306878 U.S. Department of Energy http://dx.doi.org/10.13039/100000015 Department of Energy DOE http://sws.geonames.org/6252001/ http://sws.geonames.org/4138106/ Office of Science http://dx.doi.org/10.13039/100006132 SC http://sws.geonames.org/6252001/ http://sws.geonames.org/4138106/ Basic Energy Sciences http://dx.doi.org/10.13039/100006151 BES http://sws.geonames.org/6252001/ http://sws.geonames.org/4138106/ DE-SC0012670 DE-SC0008145 The spectroscopic experiments performed by A.S. were supported jointly through ARO W911NF-15-1-0088 and AFOSR FA9550-10-1-0022. The work by E.J.S. was supported by NSF DMR-1306878. The collaboration on sample preparation between UT-Austin and UC-Riverside was supported as part of the SHINES, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Science (BES) under Award No. DE-SC0012670. K.T., X.L., D.P., and N.M.G. have received support from the SHINES. The UW team supported by U.S. DOE, BES, Materials Sciences and Engineering Division (DE-SC0008145) prepared samples and contributed to the interpretation of spectroscopic data. The samples were provided by J.Y. and D.G.M. at ORNL with support by U.S. DOE, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. E.M. acknowledges funding from the EU Graphene Flagship (CNECT-ICT-604391). X.L. also acknowledges the support from a Humboldt fellowship, which facilitated the collaboration on theoretical studies performed by V.O., G.B., M.R., and E.M.