Superconducting nanowire single photon detector on 4H-SiC substrates with saturated quantum efficiency

Abstract

On-chip single photon detection is crucial for implementing on-chip quantum communication, quantum simulation, and calculation. Superconducting nanowire single-photon detectors (SNSPDs) have become one of the essential techniques to achieve high-efficiency, on-chip, single-photon detection at scale due to their high detection efficiency, low dark count rate, and low jitter. Silicon carbide (SiC) has emerged as a promising integrated photonics platform due to its nonlinear optical processing capabilities, compatibility with CMOS technology, and outstanding quantum properties as a device for single photon sources. However, achieving high-efficiency superconducting nanowire single-photon detection on SiC substrates has yet to be demonstrated. In this study, we deposited polycrystalline NbN thin films onto 4H-SiC substrates. We also ensured that the deposited NbN thin film had a flat surface with a roughness less than 1 nm on the C-side 4H-SiC substrate through optimized chemical mechanical polishing. The NbN-SNSPD achieved a saturated quantum efficiency covering the color center emission bandwidth wavelength range (from 861 to 1550 nm) of the 4H-SiC material. These results offer a promising solution for high-efficiency single-photon detection on fully integrated quantum optical chips on 4H-SiC substrates.