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.
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%.
- 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.