Picosecond carrier dynamics in THz HgTe nanocrystals

Owing to their tunable features from
$1\ \mu \mathrm{m}$
to
$200\ \mu \mathrm{m}$
, HgTe nanocrystals are very attractive for THz technology. However, their absorption properties in the full THz range remains elusive and the carrier dynamics in THz HgTe nanocrystals are still unexplored. Here, we report significant absorption from 0.5 THz to 3 THz in large HgTe nanocrystals. Furthermore, using optical pump-THz probe measurements, we demonstrate picosecond relaxation times of nonequilibrium carriers in THz HgTe nanocrystals at room temperature. Our study provides insight on the nature of the involved transitions and also reveals the great potential of HgTe nanocrystals for the development of THz sources and photodetectors.