Giant enhancement of exciton diffusivity in two-dimensional semiconductors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33355123.
- Also identified by DOI 10.1126/sciadv.abb4823 and PMC identifier 11206464.
- Licence recorded as CC BY-NC.
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Abstract
Two-dimensional (2D) semiconductors bear great promise for application in optoelectronic devices, but the low diffusivity of excitons stands as a notable challenge for device development. Here, we demonstrate that the diffusivity of excitons in monolayer MoS<sub>2</sub> can be improved from 1.5 ± 0.5 to 22.5 ± 2.5 square centimeters per second with the presence of trapped charges. This is manifested by a spatial expansion of photoluminescence when the incident power reaches a threshold value to enable the onset of exciton Mott transition. The trapped charges are estimated to be in a scale of 10<sup>10</sup> per square centimeter and do not affect the emission features and recombination dynamics of the excitons. The result indicates that trapped charges provide an attractive strategy to screen exciton scattering with phonons and impurities/defects. Pointing towards a new pathway to control exciton transport and many-body interactions in 2D semiconductors.