Low gap superconducting single photon detectors for infrared sensitivity
Abstract
The quantum efficiency of NbN and NbTiN superconducting single photon detectors drops with decreasing photon energy. A lower gap material would enable single photon detection deeper in the infrared. We have fabricated a NbSi detector and compare its characteristics with a NbTiN device. NbSi (TC≃2 K) has a smaller superconducting gap than NbTiN or NbN (TC≃15 K). We measure the detection efficiency for a wavelength range from 1100 to 1900 nm. In this range the NbSi detector shows a 10-fold increase in relative efficiency with respect to the NbTiN detector.
- Publication:
-
Applied Physics Letters
- Pub Date:
- June 2011
- DOI:
- 10.1063/1.3599712
- Bibcode:
- 2011ApPhL..98y1102D
- Keywords:
-
- niobium compounds;
- photon counting;
- superconducting devices;
- superconducting energy gap;
- superconducting materials;
- titanium compounds;
- 85.25.Am;
- 74.25.Jb;
- 74.70.Ad;
- Superconducting device characterization design and modeling;
- Electronic structure;
- Metals;
- alloys and binary compounds