@Article{Ilin_etal2000,
author="Il{\textquoteright}in, K. S.
and Lindgren, M.
and Currie, M. A.
and Semenov, D.
and Gol{\textquoteright}tsman, G. N.
and Sobolewski, Roman
and Cherednichenko, S. I.
and Gershenzon, E. M.",
title="Picosecond hot-electron energy relaxation in NbN superconducting photodetectors",
journal="Appl. Phys. Lett.",
year="2000",
volume="76",
number="19",
pages="2752--2754",
optkeywords="NbN HEB detectors; two-temperature model; IF bandwidth",
abstract="We report time-resolved characterization of superconducting NbN hot-electron photodetectors using an electro-optic sampling method. Our samples were patterned into micron-size microbridges from 3.5-nm-thick NbN films deposited on sapphire substrates. The devices were illuminated with 100 fs optical pulses, and the photoresponse was measured in the ambient temperature range between 2.15 and 10.6 K (superconducting temperature transition TC). The experimental data agreed very well with the nonequilibrium hot-electron, two-temperature model. The quasiparticle thermalization time was ambient temperature independent and was measured to be 6.5 ps. The inelastic electron--phonon scattering time {\"I}{\quotedblbase}e--ph tended to decrease with the temperature increase, although its change remained within the experimental error, while the phonon escape time {\"I}{\quotedblbase}es decreased almost by a factor of two when the sample was put in direct contact with superfluid helium. Specifically, {\"I}{\quotedblbase}e--ph and {\"I}{\quotedblbase}es, fitted by the two-temperature model, were equal to 11.6 and 21 ps at 2.15 K, and 10({\textpm}2) and 38 ps at 10.5 K, respectively. The obtained value of {\"I}{\quotedblbase}e--ph shows that the maximum intermediate frequency bandwidth of NbN hot-electron phonon-cooled mixers operating at TC can reach 16(+4/--3) GHz if one eliminates the bolometric phonon-heating effect.",
optnote="exported from refbase (https://db.rplab.ru/refbase/show.php?record=856), last updated on Mon, 24 May 2021 18:29:10 -0500",
issn="0003-6951",
doi="10.1063/1.126480",
opturl="http://aip.scitation.org/doi/10.1063/1.126480",
opturl="https://doi.org/10.1063/1.126480"
}