High performance NbN nanowire superconducting single photon detectors fabricated on MgO substrates

TL;DR

This paper reports the development of high-performance superconducting nanowire single photon detectors made from NbN films on MgO substrates, achieving notable efficiency and compatibility with integration.

Contribution

It introduces a fabrication process for NbN SSPDs on MgO substrates with optimized film properties and demonstrates their high quantum efficiency at 1300nm.

Findings

Quantum efficiency of 20% at 1300nm

Successful fabrication on ultrathin NbN films

Optimized deposition parameters for high-quality films

Abstract

We demonstrate high-performance nanowire superconducting single photon detectors (SSPDs) on ultrathin NbN films grown at a temperature compatible with monolithic integration. NbN films ranging from 150nm to 3nm in thickness were deposited by dc magnetron sputtering on MgO substrates at 400C. The superconducting properties of NbN films were optimized studying the effects of deposition parameters on film properties. SSPDs were fabricated on high quality NbN films of different thickness (7 to 3nm) deposited under optimal conditions. Electrical and optical characterizations were performed on the SSPDs. The highest QE value measured at 4.2K is 20% at 1300nm.