Superconducting niobium nitride: a perspective from processing, microstructure, and superconducting property for single photon detectors

Abstract

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. Recent experimental results have indicated that 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.

The effect of ammonolysis conditions on the structural properties and oxidation kinetics of cubic niobium oxynitride

“…7–9 They have also been suggested as photocatalytic materials, due to their narrow band gaps and high light absorption, 10,11 energy storage-applications, such as supercapacitors, 12–14 and anode materials for rechargeable lithium-ion batteries, 15 as well as potential superconductors. 16–18 A recent computer modelling study by Abghoui et al , 7 for example, highlighted niobium nitride to be among the most promising candidates for the nitrogen reduction reaction (NRR), due to a predicted high catalytic activity for NRR, as well as a good resilience to the production of hydrogen. It was emphasized that nitride materials were highly suited to suppress the H 2 evolution reaction (HER), an essential electrocatalytic criterion for a good NRR, 19 thereby avoiding the main limitation of typical noble metal catalysts.…”

High-uniformity atomic layer deposition of superconducting niobium nitride thin films for quantum photonic integration

“…Highly uniform, homogenous thin films are a necessity for SNSPDs, as constrictions and film inhomogeneities actively suppress the critical current of the nanowire, leading to reduced timing resolution and detection efficiency, therefore necessitating operation at lower temperatures [14]. NbN thin films for SNSPDs have typically been deposited using reactive magnetron sputtering of Nb metal with N 2 gas, however, sputtering struggles to produce uniform, pinhole-free films over large areas, being limited due to its line-of-site nature and requirement of high temperatures [15,16]. Consequently, ALD of metal nitrides has received significant interest in recent years, with several studies showcasing films with high T c and J c , essential for the fabrication of high efficiency, high temporal resolution SNSPDs [17][18][19][20].…”

Heterogeneous integration of superconducting thin films and epitaxial semiconductor heterostructures with lithium niobate

“…For the latter, nitride-based superconductors are a leading material platform in the moderate temperature range because these materials exhibit much higher critical temperatures compared to Al. For example, niobium nitride (NbN) exhibits its superconducting transition at T c ≈ 16 K and is a well established material for superconducting single-photon detectors (SSPDs) [43][44][45][46][47]. SSPDs made from NbN and related compounds have been successfully demonstrated on a variety of substrates, including the materials used in this work: LiNbO 3 [48][49][50][51] and GaAs [52,53].…”