0600753 - FZÚ 2026 RIV US eng J - Journal Article
Singh, Arvind - Němec, Hynek - Kunc, J. - Kužel, Petr
Ultrafast terahertz conductivity in epitaxial graphene nanoribbons: an interplay between photoexcited and secondary hot carriers.
Journal of Physics D-Applied Physics. Roč. 58, č. 4 (2025), č. článku 045307. ISSN 0022-3727. E-ISSN 1361-6463
R&D Projects: GA ČR(CZ) GA24-10331S; GA MŠMT(CZ) EH22_008/0004594; GA MŠMT LM2023051
Institutional support: RVO:68378271
Keywords : epitaxial graphene * ultrafast photoconductivity * ultrafast carrier dynamics * terahertz
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.1, year: 2023
Method of publishing: Open access
DOI: https://doi.org/10.1088/1361-6463/ad8e71

Optical pump-terahertz probe spectroscopy was used to investigate ultrafast photo-induced charge carrier transport in graphene nanoribbons upon scaling the optical pump intensity. For low pump fluences, the deposited pump energy is rapidly redistributed through carrier-carrier scattering, producing secondary hot carriers: the picosecond THz photoconductivity then acquires a negative sign and scales linearly with an increasing pump fluence. At higher fluences, there are not enough equilibrium carriers able to accept the deposited energy, directly generated carriers start to contribute significantly to the photoconductivity with a positive sign leading to its saturation. This leads to a non-monotonic variation of the carrier mobility and plasmonic resonance frequency as a function of the pump fluence. In addition, a weak carrier localization observed at low pump fluences is progressively lifted upon increasing the pump fluence as a result of the rise of initial carrier temperature.
Permanent Link: https://hdl.handle.net/11104/0358050

Scientific data in ASEP :
Ultrafast photoconductivity in graphene nanoribbons