Niobium Nitride Research Articles

Reactive Magnesium Nitride Additive: A Drop-in Solution for Lithium/Garnet Wetting in All-Solid-State Batteries.

Garnet oxides such as Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO) are promising solid electrolyte materials for all-solid-state lithium-metal batteries because of high ionic conductivity, low electronic leakage, and wide electrochemical stability window. While LLZTO has been frequently discussed to be stable against lithium metal anode, it is challenging to achieve and maintain good solid-on-solid wetting at the metal/ceramic interface in both processing and extended electrochemical cycling. Here we address the challenge by a powder-form magnesium nitride additive, which reacts with the lithium metal anode to produce well-dispersed lithium nitride. The in situ formed lithium nitride promotes reactive wetting at the Li/LLZTO interface, which lowers interfacial resistance, increases critical current density (CCD), and improves cycling stability of the electrochemical cells. The additive recipe has been diversified to titanium nitride, zirconium nitride, tantalum nitride, and niobium nitride, thus supporting the general concept of reactive dispersion-plus-wetting. Such a design can be extended to other solid-state devices for better functioning and extended cycle life.

Reactive Magnesium Nitride Additive: A Drop‐in Solution for Lithium/Garnet Wetting in All‐Solid‐State Batteries

AbstractGarnet oxides such as Li6.4La3Zr1.4Ta0.6O12 (LLZTO) are promising solid electrolyte materials for all‐solid‐state lithium‐metal batteries because of high ionic conductivity, low electronic leakage, and wide electrochemical stability window. While LLZTO has been frequently discussed to be stable against lithium metal anode, it is challenging to achieve and maintain good solid‐on‐solid wetting at the metal/ceramic interface in both processing and extended electrochemical cycling. Here we address the challenge by a powder‐form magnesium nitride additive, which reacts with the lithium metal anode to produce well‐dispersed lithium nitride. The in situ formed lithium nitride promotes reactive wetting at the Li/LLZTO interface, which lowers interfacial resistance, increases critical current density (CCD), and improves cycling stability of the electrochemical cells. The additive recipe has been diversified to titanium nitride, zirconium nitride, tantalum nitride, and niobium nitride, thus supporting the general concept of reactive dispersion‐plus‐wetting. Such a design can be extended to other solid‐state devices for better functioning and extended cycle life.

Synthesis of ΝbN faceted grains from oxides and boron nitride with sodium

Agglomerates of ε-NbN hexagonal prismatic faceted grains with a size between 5 and 50 μm were formed by heating Nb2O5 or NbFeO4 powder and Na lump in a BN crucible at 900–1100 °C under an Ar atmosphere. Wavelength-dispersive X-ray analysis demonstrated that the ε-NbN faceted grains have a nearly stoichiometric composition. In addition to the ε-NbN grains, powders of niobium nitrides containing δ-NbN and Nb2N, and water-soluble Na3BO3 were included in the sample prepared from Nb2O5 at 1100 °C, while powders of Fe and Na3BO3, and a trace of δ-NbN were included in the sample from NbFeO4. These reactions were attributed to metathesis reactions in which the oxygen in the oxides and the nitrogen in the solid nitrogen source, BN, were replaced by the formation of Na3BO3. An extra amount of nitrogen supplied from the starting material enhances the formation of ε-NbN and suppressed the formation of δ-NbN and Nb2N.

Impedance-Matched Differential Superconducting Nanowire Detectors

Superconducting nanowire single-photon detectors (SNSPDs) are the highest-performing photon-counting technology in the near-infrared region. Because of delay-line effects, large-area SNSPDs typically trade off timing resolution and detection efficiency. This unavoidable fundamental constraint might limit their future deployment in demanding scientific applications. Here we introduce a detector design based on transmission-line engineering and differential readout for device-level signal conditioning, enabling a high system detection efficiency and a low detector jitter simultaneously. To make our differential detectors compatible with single-ended time taggers, we also engineer analog differential-to-single-ended readout electronics, with minimal impact on the system timing resolution. Our best niobium nitride differential SNSPD achieves a system detection efficiency of (83.3±4.3)% at 1550nm and (78±5)% at 775nm. The lowest system jitter is 13.0±0.4ps at 1550nm and 9.7±0.4ps at 775nm, limited by intrinsic contributions. These detectors also achieve sub-100-ps timing response at 1/100 of the maximum level, 30.7±0.4ps at 775 nm and 47.6±0.4ps at 1550nm, enabling time-correlated single-photon counting with high-dynamic-range response functions. Furthermore, because of the differential impedance-matched design, our detectors exhibit delay-line imaging capabilities and photon-number resolution. The properties and high-performance metrics achieved by our system make it a versatile photon-detection solution for quantum computing, quantum communication, and many other scientific applications.8 MoreReceived 16 December 2021Revised 7 February 2023Accepted 20 March 2023DOI:https://doi.org/10.1103/PhysRevApplied.19.044093© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasOptoelectronicsPhysical SystemsLow-temperature superconductorsNanowiresOptical sources & detectorsSuperconducting devicesTechniquesInfrared techniquesPhoton countingSingle-photon detectorsQuantum InformationCondensed Matter, Materials & Applied PhysicsAtomic, Molecular & Optical

THz optical beat-note detection with a fast superconducting hot electron bolometer operating up to 31 GHz.

We study the performance of a hot-electron bolometer (HEB) operating at THz frequencies based on superconducting niobium nitride films. We report on the voltage response of the detector over a large electrical detection bandwidth carried out with different THz sources. We show that the impulse response of the fully packaged HEB at 7.5 K has a 3 dB cutoff around 2 GHz. Remarkably, detection capability is still observed above 30 GHz in an heterodyne beating experiment using a THz quantum cascade laser frequency comb. Additionally, the HEB sensitivity has been evaluated and an optical noise equivalent power NEP of 0.8 pW/√H z has been measured at 1 MHz.

Ion-beam assisted sputtering of titanium nitride thin films

Titanium nitride is a material of interest for many superconducting devices such as nanowire microwave resonators and photon detectors. Thus, controlling the growth of TiN thin films with desirable properties is of high importance. This work aims to explore effects in ion beam-assisted sputtering (IBAS), were an observed increase in nominal critical temperature and upper critical fields are in tandem with previous work on Niobium nitride (NbN). We grow thin films of titanium nitride by both, the conventional method of DC reactive magnetron sputtering and the IBAS method, to compare their superconducting critical temperatures T_{c} as functions of thickness, sheet resistance, and nitrogen flow rate. We perform electrical and structural characterizations by electric transport and x-ray diffraction measurements. Compared to the conventional method of reactive sputtering, the IBAS technique has demonstrated a 10% increase in nominal critical temperature without noticeable variation in the lattice structure. Additionally, we explore the behavior of superconducting T_c in ultra-thin films. Trends in films grown at high nitrogen concentrations follow predictions of mean-field theory in disordered films and show suppression of superconducting T_c due to geometric effects, while nitride films grown at low nitrogen concentrations strongly deviate from the theoretical models.

High-timing-precision detection of single X-ray photons by superconducting nanowires.

Precisely acquiring the timing information of individual X-ray photons is important in both fundamental research and practical applications. The timing precision of commonly used X-ray single-photon detectors remains in the range of one hundred picoseconds to microseconds. In this work, we report on high-timing-precision detection of single X-ray photons through the fast transition to the normal state from the superconductive state of superconducting nanowires. We successfully demonstrate a free-running X-ray single-photon detector with a timing resolution of 20.1ps made of 100-nm-thick niobium nitride film with an active area of 50μm by 50μm. By using a repeated differential timing measurement on two adjacent X-ray single-photon detectors, we demonstrate a precision of 0.87ps in the arrival-time difference of X-ray photon measurements. Therefore, our work significantly enhances the timing precision in X-ray photon counting, opening a new niche for ultrafast X-ray photonics and many associated applications.

High-resistivity niobium nitride films for saturated-efficiency SMSPDs at telecom wavelengths and beyond

Incorporating a micrometer scale strip as the sensitive element in superconducting single-photon detectors can lead to significant improvements in their speed, footprint, and fabrication yield. However, the current application of microstrips has resulted in a decline in the detectors' intrinsic detection efficiency. We address this issue through the utilization of niobium nitride films with high values of resistance per square. Notably, the films used in our study possess an important characteristic of retaining high critical temperature values, which enables the devices to operate in conventional closed-cycle cryostats.

A nanocryotron memory and logic family

The development of superconducting electronics based on nanocryotrons has been limited so far to few device circuits, in part due to the lack of standard and robust logic cells. Here, we introduce and experimentally demonstrate designs for a set of nanocryotron-based building blocks that can be configured and combined to implement memory and logic functions. The devices were fabricated by patterning a single superconducting layer of niobium nitride and measured in liquid helium on a wide range of operating points. The tests show 10 − 4 bit error rates with above ± 20 % margins up to 50 MHz and the possibility of operating under the effect of an out-of-plane 36 mT magnetic field, with ± 30 % margins at 10 MHz. Additionally, we designed and measured an equivalent delay-flip-flop made of two memory cells to show the possibility of combining multiple building blocks to make larger circuits. These blocks may constitute a solid foundation for the development of nanocryotron logic circuits and finite-state machines with potential applications in the integrated processing and control of superconducting nanowire single-photon detectors.

Superconducting NbN for Strong Magnetic Field Applications: Impact of the Thin Films Intrinsic Disorder

The research on superconducting circuits for quantum information technologies progressively extends from the academic world towards the industry. Material sciences therefore become an essential lever for the development of technologies based on such circuits as they allow finding industry-compatible routes of improvements. In this context, we propose a study on the behavior of the niobium nitride (NbN), one of the most commonly used material for these devices, when exposed to strong magnetic fields. To this aim, the properties of NbN layers with the same composition but different microstructures, tuned by changing the deposition method, are compared. This study aims to establish interdependencies between the microstructure of the material and its behavior once exposed to a magnetic field. X-ray diffraction and Hall-effect characterizations are used to assess that the microstructure is significantly modified by the choice of the deposition technique. Pushing further these investigations also allowed to quantify and compare the level of disorder in both cases by extracting the Ioffe-regel and the Ginzburg-Landau parameters from characterizations of the superconducting transition temperature for several magnetic field amplitudes. This was used to conclude that in highly disordered NbN layers, the microstructure heterogeneities are responsible for a strong electron localization allowing to significantly enhance the resilience of their superconducting state under strong magnetic fields.

Electron–phonon interactions and superconductivity of β -Nb2N thin films

Niobium nitride (NbN) has attracted scientific interest due to its diverse physical properties and a variety of structural phases. The structure and superconductivity of the cubic δ-NbN phase are well established, but its hexagonal phases are not explored hitherto. In the present work, we report a simple synthesis route and a detailed study of hexagonal β-Nb2N thin films. Thermal annealing of sputtered grown α-NbN leads to a single phase β-Nb2N at 973 K as confirmed by x-ray diffraction and absorption spectroscopy. The electrical transport measurements revealed a dominance of electron–phonon interactions with a superconducting transition around 4.74 K and an upper critical field [HC2(0)] of 3.99 T. The estimated HC2(0) is well below the calculated Pauli limit, and the Maki parameter value (α < 1) indicates that HC2(0) is dominated by an orbital pair breaking effect. Finally, the obtained value of electron–phonon coupling constant (λ) is in excellent agreement with a weak coupling Bardeen–Cooper–Schrieffer value of conventional superconducting materials.

Enhanced recovery after surgery (ERAS) protocol in geriatric patients underwent unicompartmental knee arthroplasty: A retrospective cohort study.

The enhanced recovery after surgery (ERAS) pathway was formulated with the aim to reduce surgical stress response, alleviate pain and guarantee the best-fit experience of patients' perioperative period. However, the application of ERAS in geriatric patients who underwent unicompartmental knee arthroplasty (UKA) was relatively lacking. We hypothesize that UKA patients can benefit from the ERAS protocol. A total of 238 patients were recruited in this retrospective study from August 2018 to December 2021, and Oxford phase III UKA was applied to all patients. ERAS pathway included nutrition support, anesthesia mode, interoperative temperature, and blood pressure control, application of tranexamic acid, early initiation of oral intake and mobilization, and pain management. Demographic data, operation-relative variables, and postoperative complications were analyzed. Forgotten Joint Scores, Oxford Knee Score, Lysholm score, numerical rating scale, and knee range of motion were introduced to estimate the activity function and pain of surgical knee, and these variables were compared between the 2 groups. There were 117 patients in the ERAS group and 121 patients in the traditional group, respectively. The ERAS group had a shorter length of surgical incision and less intraoperative blood loss. Postoperative hemoglobin and albumin of patients in the ERAS group were better than those in the traditional group (P < .05), after 17.0 ± 10.8 months follow-up, the numerical rating scale, Lysholm, Oxford Knee Score, Forgotten Joint Scores, and knee range of motion of patients in the ERAS group were significantly better than the traditional group. The length of hospital stay for patients who underwent ERAS was 11.7 ± 3.8 days and the postoperative complication rate was lower for the ERAS group patients (P = .000 and 0.031). ERAS can reduce the length of hospital stay, and patients can achieve excellent postoperative knee function. The formulation and implementation of the ERAS protocol require good collaboration across multiple disciplines, as well as a deep understanding of the existing clinical evidence and the concept of the ERAS program.

The role of overlayered nitride electro-materials for N2 reduction to ammonia

Following our previous report on N2 reduction reaction (NRR) on the surface of nitrides, we investigated the influence of incorporation of titanium nitride as a stable and inactive-NRR material into the structure of DFT-predicted NRR-active surfaces of chromium, vanadium, niobium, and zirconium nitrides. The outcome of our density functional theory (DFT) based analyses suggests that combination of titanium nitride with vanadium nitride can enhance the potential-determining step of the reaction with up to 20% compared to pure vanadium nitride while maintaining similar number of proton-electron transfer steps for formation of two ammonia molecules. The influence of titanium nitride on chromium nitride is expected to be more pronounced as rate-determining step associated with nitrogen adsorption on the vacancy and regeneration of the catalyst improves by around 90% compared to the pure chromium nitride. This effect on niobium and zirconium nitride is, however, negative as the potential-determining step becomes larger for the case of niobium nitride, and the reaction pathway changes from nitrogen reduction to hydrogen evolution for the case of zirconium nitride. These results not only encourage experimentalists to explore these overlayered structures further in experiments, but it also opens up the avenue for considering the alloys and dopants of these nitrides via both density functional theory modelling and experiments.

High-speed detection of 1550 nm single photons with superconducting nanowire detectors

Superconducting nanowire single-photon detectors are a key technology for quantum information and science due to their high efficiency, low timing jitter, and low dark counts. In this work, we present a detector for single 1550 nm photons with up to 78% detection efficiency, timing jitter below 50 ps FWHM, 158 counts/s dark count rate, as well as a maximum count rate of 1.5 giga-counts/s at 3 dB compression. The PEACOQ detector (Performance-Enhanced Array for Counting Optical Quanta) comprises a linear array of 32 straight superconducting niobium nitride nanowires that span the mode of an optical fiber. This design supports high count rates with minimal penalties for detection efficiency and timing jitter. We show how these trade-offs can be mitigated by implementing independent readout for each nanowire and by using a temporal walk correction technique to reduce count-rate dependent timing jitter. These detectors make quantum communication practical on a 10 GHz clock.

Design and Comparison of Diamond‐ and Sapphire‐Based NbN KIDs for Fusion Plasma Polarimetric Diagnostics

Design and characterization measurements performed on kinetic inductance detectors (KIDs) produced on sapphire and polycrystalline diamond substrates are presented. Designed as part of a nuclear fusion polarimetric diagnostic, the foreseen plasma‐probing frequency of the final devices is 1.3 THz with a maximum response time under 10 ms and cross‐polarization target accuracy of 1%. These detectors are based on superconducting micro‐resonators that undergo de‐tuning upon absorption of radiation. The main characteristics of the devices include polarization sensitiveness and lumped‐elements multi‐pixel configuration produced from photo‐lithographed niobium nitride (NbN) thin films. The direct current (DC) and microwave characterization measurements highlight large differences in the thin film quality, with the superconductor deposited on diamond showing reduced critical temperature, lower critical current density, and increased values of the kinetic inductance. This difference is likely due to the higher lattice constant and thermal expansion coefficient mismatch between film and substrate in the case of diamond, with the different surface finish quality of the crystalline samples available also playing a role. The devices on both substrates show a bolometric response to THz radiation that fulfills the requirement guidelines and represent a good starting point to optimize the design for the application at hand.

The Use of Electrochemical Methods to Determine the Effect of Nitrides of Alloying Elements on the Electrochemical Properties of Titanium β-Alloys.

Titanium beta alloys represent the new generation of materials for the manufacturing of joint implants. Their Young's modulus is lower and thus closer to the bone tissue compared to commonly used alloys. The surface tribological properties of these materials should be improved by ion implantation. The influence of this surface treatment on corrosion behaviour is unknown. The surface of Ti-36Nb-6Ta, Ti-36Nb-4Zr, and Ti-39Nb titanium β-alloys was modified using nitrogen ion implantation. X-ray photoelectron spectroscopy was used for surface analysis, which showed the presence of titanium, niobium, and tantalum nitrides in the treated samples and the elimination of less stable oxides. Electrochemical methods, electrochemical impedance spectra, polarisation resistance, and Mott-Schottky plot were measured in a physiological saline solution. The results of the measurements showed that ion implantation does not have a significant negative effect on the corrosion behaviour of the material. The best results of the alloys investigated were achieved by the Ti-36Nb-6Ta alloy. The combination of niobium and tantalum nitrides had a positive effect on the corrosion resistance of this alloy. After surface treatment, the polarization resistance of this alloy increased, 2.3 × 106 Ω·cm2, demonstrating higher corrosion resistance of the alloy. These results were also supported by the results of electrochemical impedance spectroscopy.

Titanium niobium nitride knee implants are not inferior to chrome cobalt components for primary total knee arthroplasty at medium-term follow-up.

Oxidized zirconium (Oxinium), titanium nitride (TiN) or titanium niobium nitride (TiNbN) coated implants became in recent years available for an increasing amount of total knee arthroplasty (TKA) systems. The hypothesis of this study was that the use of TiNbN-coated components would not lead to inferior results compared to conventional implants and that none of the metal hypersensitivity patients receiving TiNbN-coated implants would require revision for metal allergy. This retrospective study compared 53 Titanium Niobium Nitride coated TKA with 103 conventional chrome cobalt implants of the same design. Patients were evaluated at a minimal follow-up of 3 years. No differences in clinical, radiological or patient-reported outcome measurements were observed between these groups. A survivorship of 96% without differences in revision rates was observed at medium-term follow-up of 6.5years. Metal allergy leading to contact or generalized dermatitis after TKA is very rare and usually linked to chrome or cobalt hypersensitivity. Nickel release from knee implants has not been shown to lead to cutaneous symptoms, but unexplained pain and swelling, peri-prosthetic osteolysis and component loosening remain potential issues not fully understood. The use of coated implants eliminates this factor from the diagnostic equation in case of postoperative dissatisfaction. The use of titanium niobium nitride coated implants for primary knee osteoarthritis in self-reported metal hypersensitivity patients shows similar outcomes and survivorship rates as conventional chrome cobalt TKA, with no revisions for allergy at medium-term follow-up.

Superconducting NbN-Al hybrid technology for quantum devices

The high kinetic inductance of niobium nitride (NbN) thin films can be used for an implementation of compact on-chip inductances in cryoelectronic circuits. Here, for the first time, we demonstrate the implementation of a hybrid superconducting technology that includes the fabrication of standard aluminum submicron Josephson junctions and the NbN atomic layer deposition process. As an example, we fabricated and characterized a single and array of Al Josephson junctions together with NbN interconnections. The main Al Josephson junction parameters as well as NbN superconducting properties are in a good agreement with the values obtained by our standard fabrication process. The combination of technological processes for the NbN layers with Al Josephson junction allows implementing a new generation of innovative superconducting devices for different applications.

Study of cyclic crack resistance and efficiency of cutting tool with single- and multilayer coatings based on niobium nitride

The results of studies on the effect of single- and multi-layer coatings based on niobium nitride on their cyclic crack resistance and efficiency of carbide cutting tools are presented. It is shown that the use of these coatings can significantly increase the operating time of the cutting tool before their destruction due to cracking. At the same time, the greatest effect is achieved when using multilayer coatings with a lower heat-protective layer of niobium nitride.

Effect of wear-resistant coatings based on niobium nitride on thermal and stress states of cutting tool

The results of studies of the effect of coatings based on niobium nitride on the contact characteristics, thermal and stress states of the cutting wedge of a carbide tool are presented. It is shown that the use of these coatings redistributes heat flows in the cutting zone, contact temperatures and specific loads acting on the front surface of the cutting tool, which leads to an improvement in the thermal and stress state. The greatest effect is achieved when using multilayer coatings.