The Interplay of Phonons and Subgap States Governs Ultrafast Carrier Dynamics in Layered HgPSe₃.
5 affiliations
- 1Department of Physics, Politecnico di Milano, 20133 Milan, Italy.
- 2Department of Semiconductor Materials Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
- 3Istituto Italiano di Tecnologia, Milano 20134, Italy.
- 4Department of Chemistry, National Institute of Technology Warangal, Telangana 506004, India.
- 5Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic.
Abstract
Two-dimensional van der Waals materials display rich nonequilibrium physics due to their reduced dimensionality and strong light-matter interactions. Layered metal phosphorus trichalcogenides (MPX₃) feature bandgaps spanning the visible to ultraviolet range and exhibit a complex interplay between excitons, phonons, and defects. Here we use static and time-resolved photoluminescence and femtosecond broadband transient reflectivity to investigate the temperature-dependent ultrafast carrier dynamics in layered HgPSe₃, a semiconductor with a quasi-direct bandgap near 2 eV. We identify distinct sub-bandgap photoluminescence features that become prominent at low temperature. Their temperature and fluence dependence strongly indicate radiative recombination involving localized states. The transient reflectivity map displays three features associated with interband optical transitions in the visible range, as corroborated by density functional theory band structure calculations. These features exhibit fluence-dependent decay dynamics, indicating a competition between carrier localization into sub-bandgap states, state-filling effects that limit the available electronic phase space for hot-carrier relaxation, and phonon-bottleneck-limited carrier cooling. Our results provide new insights into the ultrafast carrier dynamics of HgPSe₃ and establish a framework for understanding the role of sub-bandgap states in MPX₃ semiconductors, with potential implications for broadband optoelectronic and photodetection applications.
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BibTeX
@article{baserga2026interplay,
title = {{The Interplay of Phonons and Subgap States Governs Ultrafast Carrier Dynamics in Layered HgPSe₃.}},
author = {Alessandro Baserga and Miłosz Rybak and Micol Bertolotti and Antonella Treglia and Samim Sardar and Valentino Jadriško and Matteo Ghezzi and Giuseppe Maria Paternò and Cosimo D'Andrea and Annamaria Petrozza and Zdenek Sofer and Artur P Herman and Robert Kudrawiec and Giulio Cerullo and Giulia Folpini and Nikolas Antonatos and Christoph Gadermaier and Stefano Dal Conte},
journal = {The journal of physical chemistry. C, Nanomaterials and interfaces},
year = {2026},
month = oct,
doi = {10.1021/acs.jpcc.6c03448},
url = {https://europepmc.org/article/MED/42899156},
note = {CC BY},
}
RIS
TY - JOUR
TI - The Interplay of Phonons and Subgap States Governs Ultrafast Carrier Dynamics in Layered HgPSe₃.
AU - Alessandro Baserga
AU - Miłosz Rybak
AU - Micol Bertolotti
AU - Antonella Treglia
AU - Samim Sardar
AU - Valentino Jadriško
AU - Matteo Ghezzi
AU - Giuseppe Maria Paternò
AU - Cosimo D'Andrea
AU - Annamaria Petrozza
AU - Zdenek Sofer
AU - Artur P Herman
AU - Robert Kudrawiec
AU - Giulio Cerullo
AU - Giulia Folpini
AU - Nikolas Antonatos
AU - Christoph Gadermaier
AU - Stefano Dal Conte
PY - 2026
DA - 2026/10/01
JO - The journal of physical chemistry. C, Nanomaterials and interfaces
DO - 10.1021/acs.jpcc.6c03448
UR - https://europepmc.org/article/MED/42899156
AB - Two-dimensional van der Waals materials display rich nonequilibrium physics due to their reduced dimensionality and strong light-matter interactions. Layered metal phosphorus trichalcogenides (MPX₃) feature bandgaps spanning the visible to ultraviolet range and exhibit a complex interplay between excitons, phonons, and defects. Here we use static and time-resolved photoluminescence and femtosecond broadband transient reflectivity to investigate the temperature-dependent ultrafast carrier dynamics in layered HgPSe₃, a semiconductor with a quasi-direct bandgap near 2 eV. We identify distinct sub-bandgap photoluminescence features that become prominent at low temperature. Their temperature and fluence dependence strongly indicate radiative recombination involving localized states. The transient reflectivity map displays three features associated with interband optical transitions in the visible range, as corroborated by density functional theory band structure calculations. These features exhibit fluence-dependent decay dynamics, indicating a competition between carrier localization into sub-bandgap states, state-filling effects that limit the available electronic phase space for hot-carrier relaxation, and phonon-bottleneck-limited carrier cooling. Our results provide new insights into the ultrafast carrier dynamics of HgPSe₃ and establish a framework for understanding the role of sub-bandgap states in MPX₃ semiconductors, with potential implications for broadband optoelectronic and photodetection applications.
SN - 1932-7447
SN - 1932-7455
ER -