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Ultrafast Charge Transfer-Induced Unusual Nonlinear Optical Response in ReSe 2 /ReS 2 Heterostructure.

Authors :
Ge Y
Tan J
Xu G
Feng X
Li E
Wang Y
Lu C
Xu X
Source :
ACS nano [ACS Nano] 2024 Oct 22. Date of Electronic Publication: 2024 Oct 22.
Publication Year :
2024
Publisher :
Ahead of Print

Abstract

Ultrafast charge transfer in van der Waals heterostructures can effectively engineer the optical and electrical properties of two-dimensional semiconductors for designing photonic and optoelectronic devices. However, the nonlinear absorption conversion dynamics with the pump intensity and the underlying physical mechanisms in a type-II heterostructure remain largely unexplored, yet hold considerable potential for all-optical logic gates. Herein, two-dimensional ReSe <subscript>2</subscript> /ReS <subscript>2</subscript> heterostructure is designed to realize an unusual transition from reverse saturable absorption to saturable absorption (SA) with a conversion pump intensity threshold of approximately 170 GW/cm <superscript>2</superscript> . Such an intriguing phenomenon is attributed to the decrease of two-photon absorption (TPA) of ReS <subscript>2</subscript> and the increase of SA of ReSe <subscript>2</subscript> with the pump intensity. Based on the characterization results of X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, femtosecond transient absorption spectrum, Kelvin probe force microscopy, and density functional theory calculation, a type-II charge-transfer-energy level model is proposed combined with the TPA of ReS <subscript>2</subscript> and SA of ReSe <subscript>2</subscript> processes. The results reveal the critical role of ultrafast interfacial charge transfer in tuning the unusual nonlinear absorption and improving the SA of ReSe <subscript>2</subscript> /ReS <subscript>2</subscript> under different excitation wavelengths. Our finding deepens the understanding of nonlinear absorption physical mechanisms in two-dimensional heterostructure materials, which may further diversify the nonlinear optical materials and photonic devices.

Details

Language :
English
ISSN :
1936-086X
Database :
MEDLINE
Journal :
ACS nano
Publication Type :
Academic Journal
Accession number :
39437429
Full Text :
https://doi.org/10.1021/acsnano.4c11372