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Near-unity photoluminescence quantum yield in MoS2

Near-unity photoluminescence quantum yield in MoS2(A) Pump-power dependence of the QY for as-exfoliated and treated MoS2. Dashed lines show the recombination model. (B and C) PL images of a MoS2 monolayer before (B) and after treatment (C). Insets show optical micrographs.

Scientific Achievement
Demonstrated an opto-electronically perfect monolayer semiconductor using chemical treatments for defect passivation.

Significance and Impact
Developed a treatment using an organic super acid to repair/passivate defects in MoS2 monolayers, as a result the photoluminescence QY can be enhanced from <1% to >95%.

Research Details

  • Monolayer semiconductors were found to not show measureable Shockley-Read-Hall recombination.
  • Model using biexcitonic and defect-mediated recombination was developed for monolayer semiconductors.
  • After treatment the radiative lifetime in MoS2 was found to be ~10 ns.
  • The treatment is air stable for >1 week.

M. Amani, D.-H. Lien, D. Kiriya, J. Xiao, A. Azcatl, J. Noh, S. R. Madhvapathy, R. Addou, KC Santosh, M. Dubey, K. Cho, R. M. Wallace, S.-C. Lee, J.-H. He, J. W. Ager III, X. Zhang, E. Yablonovitch, and A. Javey, Science 350(6264) 1065 (2015)