Low noise NbN superconducting hot electron bolometer mixers at 1.9 and 2.5 THz
Abstract
NbN phonon-cooled hot electron bolometer mixers (HEBs) have been realized with negligible contact resistance between the bolometer itself and the contact structure. Using a combination of in situ cleaning of the NbN film and the use of an additional superconducting interlayer of a 10 nm NbTiN layer between the Au of the contact structure and the NbN film superior noise temperatures have been obtained as low as 950 K at 2.5 THz and 750 K at 1.9 THz. Here we address in detail the DC characterization of these devices, the interface transparencies between the bolometers and the contacts and the consequences of these factors on the mixer performance.
- Publication:
-
Superconductor Science Technology
- Pub Date:
- May 2004
- DOI:
- 10.1088/0953-2048/17/5/026
- Bibcode:
- 2004SuScT..17S.224H