Localized coherent phonon generation in monolayer MoSe2 from ultrafast exciton trapping at shallow traps.
Nanoscale Horiz
; 8(9): 1282-1287, 2023 Aug 21.
Article
in En
| MEDLINE
| ID: mdl-37470115
ABSTRACT
We report spectroscopic evidence for the ultrafast trapping of band edge excitons at defects and the subsequent generation of defect-localized coherent phonons (CPs) in monolayer MoSe2. While the photoluminescence measurement provides signals of exciton recombination at both shallow and deep traps, our time-resolved pump-probe spectroscopy on the sub-picosecond time scale detects localized CPs only from the ultrafast exciton trapping at shallow traps. Based on occupation-constrained density functional calculations, we identify the Se vacancy and the oxygen molecule adsorbed on a Se vacancy as the atomistic origins of deep and shallow traps, respectively. Establishing the correlations between the defect-induced ultrafast exciton trapping and the generation of defect-localized CPs, our work could open up new avenues to engineer photoexcited carriers through lattice defects in two-dimensional materials.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nanoscale Horiz
Year:
2023
Document type:
Article
Publication country:
ENGLAND
/
ESCOCIA
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GB
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GREAT BRITAIN
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INGLATERRA
/
REINO UNIDO
/
SCOTLAND
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UK
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UNITED KINGDOM