Superconducting NbN Hot Electron Bolometer with an Nb5N6 Buffer Layer

In this paper, the superconducting NbN hot electron bolometer terahertz detector with an Nb
₅
N
₆
buffer layer was fabricated on the Si substrate. The Nb
₅
N
₆
buffer layer can significantly improve the superconductivity of ultra-thin NbN films. Preliminary results show that with a 30-nm-thick buffer, the zero resistance superconducting transition temperature of a 6-nm-thick NbN film device is 12.6 K, and the superconducting critical current of the device is increased by four times. The noise temperature, IF bandwidth and direct detection sensitivity of the device will be further characterized in following experiments.