NbN Superconducting Devices

Daogang Sun, Hongkai Shi, Runfeng Su +6 more

In this paper, the superconducting NbN hot electron bolometer terahertz detector with an Nb5N6buffer layer was fabricated on the Si substrate. The Nb5N6buffer 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.

Alexandre Shoji

Hongkai Shi, Daogang Sun, Runfeng Su +6 more

Superconducting hot electron bolometer (HEB) were fabricated with Nb5N6buffered NbN on Si substrate. We present the result that the Nb5N6buffer layer can significantly improve the superconductivity of NbN HEB. The 2.5–5 THz superconducting HEB device has been fabricated successfully. We also do some research on devices which work at varied temperature. It is shown that our buffered HEB device could work at relatively high temperature, which means more possibility of applications in the future.

Alexander A. Korneev, Gregory N Gol'tsman, Joonas T. Peltonen +8 more

Nicholas Cucciniello, Derek Lee, Henry Y. Feng +5 more

Superconducting niobium nitride (NbN) continues to be investigated decades on, largely in part to its advantageous superconducting properties and wide use in superconducting electronics. Particularly, NbN-based superconducting nanowire single-photon detectors (SNSPDs) have shown exceptional performance and NbN remains as the material of choice in developing future generation quantum devices. In this perspective, we describe the processing-structure-property relationships governing the superconducting properties of NbN films. We further discuss the complex interplay between the material properties, processing parameters, substrate materials, device architectures, and performance of SNSPDs. We also highlight the latest progress in optimizing SNSPD performance parameters.

Photon Detectors, Jeffrey A. Stern, William H. Farr