Trion-Induced Negative Photoconductivity in Monolayer MoS[subscript 2]
Name
PhysRevLett.113.166801.pdf
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Author(s)
Lee, Y.-H.
Ling, X.
Akselrod, Gleb Markovitch
Lui, Chun Hung
Frenzel, Alex James
Pilon, Daniel Victor
Kong, Jing
Gedik, Nuh
Date Issued
October 2014
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Lui, C. H., et al. "Trion-Induced Negative Photoconductivity in Monolayer MoS[subscript 2]." Phys. Rev. Lett. 113, 166801 (October 2014). © 2014 American Physical Society
Version
Final published version
Abstract
Optical excitation typically enhances electrical conduction and low-frequency radiation absorption in semiconductors. We, however, observe a pronounced transient decrease of conductivity in doped monolayer molybdenum disulfide (MoS[subscript 2]), a two-dimensional (2D) semiconductor, using ultrafast optical-pump terahertz-probe spectroscopy. In particular, the conductivity is reduced to only 30% of its equilibrium value at high pump fluence. This anomalous phenomenon arises from the strong many-body interactions in the 2D system, where photoexcited electron-hole pairs join the doping-induced charges to form trions, bound states of two electrons and one hole. The resultant increase of the carrier effective mass substantially diminishes the conductivity.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.113.166801
