Year: 2026
Type: article
Abstract: Excitation power and energy dependent photoluminescence (PL) and transient absorption spectroscopy (TAS) studies are carried out on chemical vapour deposition grown monolayer-MoS 2 films to understand the process of trion formation. The study shows that the excitation with sufficiently low photon energy results in the creation of trions directly in the K / K ′ valleys through photon absorption followed by phonon scattering events. On the other hand, excitation energy sufficiently larger than the band-gap can generate the carriers away from the K / K ′ valleys. Dissimilarity in the rates of relaxation of the photo-excited electrons and the holes to the bottom of the K / K ′ valleys results in the transformation of the excitons residing there into trions. Our TAS study clearly demonstrates a temporary increase of the trion population in the K / K ′ valleys. Moreover, excitation intensity dependent PL spectroscopy performed under above-band-gap excitation, also suggests the coexistence of both the pathways of trion generation in this material. This conclusion is further validated by a rate equation model. Our findings provide valuable insight into the formation of trions in monolayer transition metal dichalcogenides, which could be crucial in designing valleytronic devices based on trions.
Authors: Faiha Mujeeb, Arkaprava Chowdhury, Anindya Datta, Subhabrata Dhar
Institution: Indian Institute of Technology Bombay
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,325
Award: G226746323
OpenAlex ID: W7140216269
FWCI:
Cites:
Cited by:
Related to: