Comprehensive excited state carrier dynamics of 2D selenium: One-photon and multi-photon absorption regimes

Semiconductors play a critical role in optoelectronic applications, and recent research has identified group-VI 2D semiconductors as promising materials for this purpose. Here, we report the comprehensive excited state carrier dynamics of bilayer, two-dimensional (2D) selenium (Se) in one-photon and...

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Bibliographic Details
Published in:Applied physics letters 2023-07, Vol.123 (2)
Main Authors: Prodhan, Sayan, Chauhan, Kamlesh Kumar, Singha, Tara, Karmakar, Manobina, Maity, Nikhilesh, Nadarajan, Renjith, Kumbhakar, Partha, Tiwary, Chandra Sekhar, Singh, Abhishek Kumar, Shaijumon, Manikoth M., Datta, Prasanta Kumar
Format: Article
Language:English
Subjects:
Absorption cross sections
Applied physics
Bilayers
Carrier lifetime
Carrier recombination
Energy gap
Excitation
Multiphoton absorption
Optoelectronics
Photometers
Photons
Selenium
Semiconductors
Surface chemistry
Surface defects
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Summary:Semiconductors play a critical role in optoelectronic applications, and recent research has identified group-VI 2D semiconductors as promising materials for this purpose. Here, we report the comprehensive excited state carrier dynamics of bilayer, two-dimensional (2D) selenium (Se) in one-photon and multi-photon absorption regimes using transient reflection (TR) spectroscopy. Carrier lifetime obtained from TR measurement is used to theoretically predict the photo-responsivity for 2D Se photo-detectors operating in the one-photon-absorption regime. We also calculate a giant two-photon absorption cross section of 2.9 × 10 5   GM at 750 nm hinting possible application of 2D Se as a sub-bandgap photo-detector. The carrier recombination process is dominated by surface and sub-surface defect states in one- and multi-photon absorption regimes, respectively, resulting nearly one order increased carrier lifetime in a three-photon-absorption regime (1700 ps) compared to a one-photon-absorption regime (103 ps). Femtosecond Z-scan measurement shows saturation behavior for above bandgap excitation, further indicating the possibility of 2D Se as a saturable absorber material for passive Q-switching. Our study provides comprehensive insight into the excited state carrier dynamics of bilayer 2D Se and highlights its potential as a versatile material for various linear and non-linear optoelectronic applications.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0156843