POS5-1234
Optical study of MoS2/Cu2O Heterostructures to Elucidate Auger-Assisted Non-linear Electron Uphill Transfer
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Jaewon Heo (Korea Institute of Science and Technology)
Co-Author(s)
Abstract
Interfacial charge transfer in semiconductor heterostructures is generally governed by band alignment, with carriers transfer along energetically favorable pathways. In contrast, uphill electron transfer across an unfavorable conduction band offset is not expected from equilibrium band alignment alone and requires nonequilibrium carrier dynamics. Here, we investigate Auger-assisted uphill electron transfer in a MoS₂/Cu₂O heterostructure. Compared with the pristine MoS2 film, the MoS2/Cu2O heterostructure shows photoluminescence (PL) quenching and suppression of trion emission, suggesting interfacial charge transfer. Under selective 690 nm excitation of the MoS2 A-exciton, ultrafast transient absorption spectroscopy reveals a fluence-dependent acceleration of the A-exciton bleach decay, with its characteristic decay time decreasing from approximately 10 to 4 ps, accompanied by the increase of a distinct Cu₂O bleach. These correlated fluence dependent dynamics are consistent with an Auger-assisted process in which exciton–exciton interactions in MoS₂ provide sufficient excess energy for electrons to overcome the unfavorable conduction band offset and transfer into the Cu₂O. Our results demonstrate that many-body interactions can enable energetically forbidden uphill electron transfer, providing a promising strategy for manipulating nonequilibrium carrier dynamics in mixed-dimensional heterostructure.
