THz intraband absorption in HgTe nanocrystals in the linear and nonlinear regimes
Abstract
With their tunable intraband absorption in the THz range and carrier dynamics on the order of tens of picoseconds, large HgTe nanocrystals (NCs) hold strong potential for THz optoelectronic devices, including modulators and detectors. Their THz intraband absorption has been attributed to multiple transitions of single carriers between quantized states. However, since most investigations have been limited to room temperature, many fundamental physical questions remain open. Here, we investigate the THz intraband absorption in both linear and nonlinear regimes across a broad temperature range. Our results highlight the essential role of thermally activated carriers in the linear regime, which has been so far neglected in existing models, and show that nonlinear intraband absorption in large HgTe NCs arises from an increase in chemical potential combined with changes in electronic temperature, both influenced by saturation effects associated with the progressive filling of electronic states. Furthermore, using mid-infrared pump–THz probe experiments, we probe the carrier dynamics and demonstrate that surface traps and ligand modes have a negligible effect on hot carrier recombination. The dominant recombination pathway is attributed to non-radiative interband processes mediated by optical phonon emission. This work provides new insight into the physical mechanisms underlying the THz intraband absorption of HgTe NCs in both linear and nonlinear regimes, refines their theoretical description, and highlights the potential of large HgTe NCs for THz optoelectronic devices such as modulators and detectors.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (14)
A. Fournier
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
N. Nilforoushan
Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques 2 , Paris,
I. Abdourahamane
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
D. Gacemi
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
J. Tignon
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
S. Dhillon
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
J.-B. Brubach
Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin 3 , F-91192 Gif sur Yvette,
C. Taverna
Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin 3 , F-91192 Gif sur Yvette,
P. Roy
Y. Prado
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 4 , 75005 Paris,
F. Carossella
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
R. Ferreira
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,
E. Lhuillier
Sorbonne Université, CNRS, Institut des NanoSciences de Paris 4 , 75005 Paris,
J. Mangeney
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité 1 , Paris F-75005,