Characterization of terahertz detectors based on niobium nitride superconducting tunnel junctions
Terahertz direct detectors based on superconducting tunnel junctions (STJs) have the merits of short response time, large dynamic range and relatively high operating temperature, providing a good choice for terahertz detection. Compared with commonly used niobium STJs, niobium nitride (NbN) ones have a high transition temperature close to 16K. Hence they might be useful for terahertz detection operating at temperatures well above the LHe temperature of 4.2K. In this paper, we investigate the properties of NbN STJ detectors at different bath temperatures. Detailed experiment results are given.