@Article{Siddiqi+Prober2004,
author="Siddiqi, I.
and Prober, D. E.",
title="Nb--Au bilayer hot-electron bolometers for low-noise THz heterodyne detection",
journal="Applied Physics Letters",
year="2004",
volume="84",
number="8",
pages="1404",
optkeywords="HEB; mixers; dynamic range; saturation; LO power; local oscillator power; Nb",
abstract="The sensitivity of present Nb diffusion-cooled hot-electron bolometer (HEB) mixers is not quantum limited, and can be improved by reducing the superconducting transition temperature TC. Lowering TC reduces thermal fluctuations, resulting in a decrease of the mixer noise temperature TM. However, lower TC mixers have reduced dynamic range and saturate more easily due to background noise. We present 30 GHz microwave measurements on a bilayer HEB system, Nb--Au, in which TC can be tuned with Au layer thickness to obtain the maximum sensitivity for a given noise background. These measurements are intended as a guide for the optimization of THz mixers. Using a Nb--Au mixer with TC = 1.6 K, we obtain TM = 50 K with 2 nW of local oscillator (LO) power. Good mixer performance is observed over a wide range of LO power and bias voltage and such a device should not exhibit saturation in a THz receiver.",
optnote="exported from refbase (https://db.rplab.ru/refbase/show.php?record=571), last updated on Sun, 05 Apr 2009 18:18:46 -0500",
issn="0003-6951",
doi="10.1063/1.1646726",
opturl="http://link.aip.org/link/APPLAB/v84/i8/p1404/s1&Agg=doi",
opturl="https://doi.org/10.1063/1.1646726"
}