TY  - JOUR
AU  - Siddiqi, I.
AU  - Prober, D. E.
PY  - 2004
DA  - 2004//
TI  - Nb–Au bilayer hot-electron bolometers for low-noise THz heterodyne detection
T2  - Appl. Phys. Lett.
JO  - Applied Physics Letters
SP  - 1404
VL  - 84
IS  - 8
KW  - HEB
KW  - mixers
KW  - dynamic range
KW  - saturation
KW  - LO power
KW  - local oscillator power
KW  - Nb
AB  - 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.
SN  - 0003-6951
UR  - http://link.aip.org/link/APPLAB/v84/i8/p1404/s1&Agg=doi
UR  - https://doi.org/10.1063/1.1646726
DO  - 10.1063/1.1646726
N1  - exported from refbase (https://db.rplab.ru/refbase/show.php?record=571), last updated on Sun, 05 Apr 2009 18:18:46 -0500
ID  - Siddiqi+Prober2004
ER  -