Augmented Extraction Efficiency of a Hot D Exciton in MoS 2 via Intervalley Scattering

Prolonging hot carrier cooling, a crucial factor in optoelectronic applications, including hot carrier photovoltaics, presents a significant challenge. High-energy band-nesting excitons within parallel bands offer a promising and underexplored avenue for addressing this issue. Here, we exploit an ex...

Full description

Saved in:
Bibliographic Details
Published in:Nano letters 2024-09, Vol.24 (36), p.11163-11169
Main Authors: Tran, Thanh-Xuan, Jang, Yu Jin, Vu, Van-Tu, Jung, Chan-Woo, Do, Van Dam, Jin, Yeongrok, Lee, Jaekwang, Kim, Hyunjung, Kim, Ji-Hee
Format: Article
Language:English
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Prolonging hot carrier cooling, a crucial factor in optoelectronic applications, including hot carrier photovoltaics, presents a significant challenge. High-energy band-nesting excitons within parallel bands offer a promising and underexplored avenue for addressing this issue. Here, we exploit an exceptional D exciton cooling prolongation of 2 to 3 orders of magnitude compared to sub-picosecond in typical transition metal dichalcogenides (TMDs) owing to the complex Coulomb environment and the sequential and mismatch-valley relaxation. Simultaneously, the intervalley scattering upconversion of band-edge excitons with the slow D exciton formation in the metastable Γ valley/hill also reduces the cooling rate. We successfully extract D and C excitons as hot carriers through integrating with various thicknesses of TiO , achieving the highest efficiency of 98% and 85% at a Ti thickness of 2 nm. Our findings highlight the potential of band-nesting excitons for extending hot carrier cooling time, paving the way for advancements in hot carrier-based optoelectronic devices.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.4c01837