Title :
Comparison of the THz Direct-Detection Behaviors of Nb and NbN Superconducting Tunnel Junctions
Author :
Shen, Xiao-Fang ; Cao, Xue-Song ; Li, Jing ; Shi, Sheng-Cai
Author_Institution :
Purple Mountain Obs., Chinese Acad. of Sci., Nanjing
Abstract :
Superconducting SIS (superconductor-insulator-superconductor) tunnel junctions are promising application prospect in the incoherent detection of astronomy observation. In this paper, the direct detection performances of Nb and NbN based superconducting SIS junctions, which cover about 250 GHz and 140 GHz centered at 600 GHz respectively, are characterized at a bath temperature of 4.2 K. The experiments show that Nb and NbN based SIS junctions have a current shot noise of 2.5 times 10-12 and 3.1 times 10-12 A/radicHz, a current responsivity of 303 and 187 A/W (corresponding to the quantum efficiency of 0.67 and 0.43) respectively. Thus their respective NEPs are 8.4 times 10-15 and 1.7 times 10-14W/radic Hz.
Keywords :
astronomy; superconductor-normal-superconductor devices; THz direct-detection behaviors; astronomy observation; frequency 140 GHz; frequency 250 GHz; frequency 600 GHz; superconductor-insulator-superconductor tunnel junctions; temperature 4.2 K; Circuit optimization; Detectors; Frequency; Josephson junctions; Niobium; Signal to noise ratio; Superconducting device noise; Superconducting devices; Superconducting films; Temperature;
Conference_Titel :
Millimeter Waves, 2008. GSMM 2008. Global Symposium on
Conference_Location :
Nanjing
Print_ISBN :
978-1-4244-1885-5
Electronic_ISBN :
978-1-4244-1886-2
DOI :
10.1109/GSMM.2008.4534567
