Tantalum Nitride Research Articles

Tantalum nitride nanotube structured electrode for non-enzymatic hydrogen peroxide sensing via photoelectrochemical route

• A non-enzymatic photoelectrochemical (PEC) H 2 O 2 sensor has been constructed. • The sensor consists of Ta 3 N 5 nanotube electrode, without any other catalysts. • High sensitivity of 167.9 uA cm −2 mM −1 has been obtained for H 2 O 2 sensing. • The work expands the application of Ta 3 N 5 in the field of chemical analysis. Photoelectrochemical (PEC) sensing holds great promise in the field of analytical chemistry owing to its high sensitivity, low cost and simple equipment. In this paper, tantalum nitride (Ta 3 N 5 ) photoanode is fabricated for PEC H 2 O 2 sensor through an anodization procedure combined with subsequent nitridation in NH 3 atmosphere. The crystalline phase, morphology and light adsorption property of Ta 3 N 5 are characterized by X-ray diffraction, scanning electron microscope and UV–vis diffuse reflectance spectrophotometer, the results show that Ta 3 N 5 has nanotube structure and can absorb light to 620 nm. The PEC tests exhibit Ta 3 N 5 photoelectrode has much higher current and lower onset potential for hydrogen peroxide (H 2 O 2 ) oxidation than H 2 O oxidation, indicating H 2 O 2 possesses faster reaction kinetics over Ta 3 N 5 surface. Furthermore, the Ta 3 N 5 photoelectrode exhibited a high sensitivity of 167.9 μA cm −2 mM −1 for H 2 O 2 determination in the concentration range of 0.1 ∼ 2.6 mM. It is supposed that the fast extraction of hole by H 2 O 2 on the Ta 3 N 5 electrode surface is the key for the high sensing performance achieved in our fabricated PEC sensor.

Effect of capping layer on the ferroelectricity of hafnium oxide

In this work, we investigate the effect of a capping layer of aluminum oxide (AlOx) on dopant-free hafnium-oxide (HfO2) ferroelectric layer. According to our experimental results, the AlOx-capped HfO2 ferroelectric capacitor exhibits the significant improvement on ferroelectric polarization strength and also presents a comparable electrical stress resistance in comparison with control HfO2 ferroelectric capacitor with a very weak ferroelectric hysteresis. An additional nitrogen treatment on AlOx capping layer effectively alleviate the stress-induced generation of defect traps near the interface of tantalum nitride (TaN) electrode under negative-bias voltage stress. Therefore, the performance improvement can be ascribed to the introduction of AlOx capping layer and well-controlled nitrogen plasma treatment to improve interface traps and stabilize the ferroelectric phase transformation during high-temperature annealing process.

Influence of nitrogen concentration on electrical, mechanical, and structural properties of tantalum nitride thin films prepared via DC magnetron sputtering

Influence of nitrogen concentration on electrical, mechanical, and structural properties of tantalum nitride thin films prepared via DC magnetron sputtering

Area-Selective Deposition of Tantalum Nitride with Polymerizable Monolayers: From Liquid to Vapor Phase Inhibitors

Area-Selective Deposition of Tantalum Nitride with Polymerizable Monolayers: From Liquid to Vapor Phase Inhibitors

A Simple Method for Fabricating Ink Chamber of Inkjet Printheads.

The process of fabricating chambers is becoming more important for inkjet printheads. However, there are some problems with the majority of present fabrication methods, such as nozzle structural deformation, blocked chambers, and collapsed chambers. In this paper, we propose a new process for preparing printhead chips by bonding tantalum nitride thin-film heaters and SU-8 chamber film using UV curing optical adhesive. This process simplifies the preparation process of printhead chips and overcomes the limitations of the traditional adhesive bonding process. Firstly, a chamber film was prepared by the molding lithography process based on a PDMS mold. The chamber film was then bonded with the membrane heater by the adhesive bonding process based on film transfer to form a thermal bubble printhead chip. Finally, the chip was integrated with other components to form a thermal inkjet printhead. The results show that the overflow width of bonding interface of 3.10 μm and bonding strength of 3.3 MPa were achieved. In addition, the printhead could stably eject polyvinyl pyrrolidone binder droplets, which are expected to be used for binder-jetting printing of powder such as ceramics, metals, and sand molds. These results might provide new clues to better understand the adhesive bonding process based on film transfer and the new applications of inkjet printheads.

15 N/14N isotopic exchange in the dissociative adsorption of N2 on tantalum nitride cluster anions Ta3N3−

Adsorption and activation of dinitrogen (N2) is an indispensable process in nitrogen fixation. Metal nitride species continue to attract attention as a promising catalyst for ammonia synthesis. However, the detailed mechanisms at a molecular level between reactive nitride species and N2 remain unclear at elevated temperature, which is important to understand the temperature effect and narrow the gap between the gas phase system and condensed phase system. Herein, the 14N/15N isotopic exchange in the reaction between tantalum nitride cluster anions Ta314N3− and 15N2 leading to the regeneration of 14N2/14N15N was observed at elevated temperature (393−593 K) using mass spectrometry. With the aid of theoretical calculations, the exchange mechanism and the effect of temperature to promote the dissociation of N2 on Ta3N3− were elucidated. A comparison experiment for Ta314N4−/15N2 couple indicated that only desorption of 15N2 from Ta314N415N2− took place at elevated temperature. The different exchange behavior can be well understood by the fact that nitrogen vacancy is a requisite for the dinitrogen activation over metal nitride species. This study may shed light on understanding the role of nitrogen vacancy in nitride species for ammonia synthesis and provide clues in designing effective catalysts for nitrogen fixation.

Understanding the high performance of PdSn–TaN(tantalum nitride)/C electrocatalysts for the methanol oxidation reaction: coupling nitrides and oxophilic elements

Palladium-modified transition metal nitrides (TaN) are investigated as electrochemical methanol oxidation reaction (MOR) catalysts. Combined in situ ATR-SEIRAS and DFT results demonstrate PdSn–TaN/C as an effective material to enhance MOR activity.

Design of semitransparent tantalum nitride photoanode for efficient and durable solar water splitting

A semitransparent Ta3N5 photoanode is designed for efficient and durable solar water splitting. The Ta3N5-CuInSe2 tandem device exhibits an initial and stabilized solar-to-hydrogen efficiency of ∼9% (highest for metal oxides/nitrides) and 4%, respectively.

The effective Work-Function of atomic layer deposited TaN thin film using TBTDET precursor and NH3 reactant gas

We investigated the effect of capping metals and post annealing on the effective work function (EWF) of atomic layer deposited (ALD) tantalum nitride (TaN) using a metal oxide semiconductor (MOS) device with HfO2 gate dielectric. The tris(diethylam-ido)(tert-butylimido) tantalum (TBTDET) precursor and ammonia (NH3) were used as the tantalum precursor and the reactant gas, respectively. Increasing ALD TaN thickness leads to higher EWF regardless of the capping metals. When aluminum (Al) is used as the capping metal, the EWF range is 4.06 eV to 4.45 eV, which is suitable for the gate electrode of the n-type device, and for the tungsten (W) capping metal, the EWF range is 4.43 eV to 4.80 eV, acceptable for the gate electrode of the p-type device. These results are attributed that Al causes oxygen-scavenging, resulting in more oxygen vacancies within HfO2, whereas W reacts little with oxygen. The EWF versus ALD TaN thickness dependence of the Al and W capping cases is 55.7 meV/nm and 52.8 meV/nm, respectively. Additional heat treatment further increases EWF further for both cases, which is attributed to the reduction of carbon contents within TaN.

Influences of aluminum doping on the microstructures and electrical properties of tantalum nitride thin films before and after annealing

Ta–N–Al thin films were produced by reactive sputtering with two different TaAl alloys (Al 10 at.% and 20 at.%) for use as resistive materials for thin film chip resistors. Changing the N2 gas flow of the N2/Ar plasma and the Al ratio in TaAl alloy resulted in different microstructures and electrical properties of the Ta–N–Al thin film. The resistivity of the thin film sputtered by TaAl (Al 20 at.%) alloy was 1.23 times that sputtered by Ta under 20% N2/Ar. After deposition, rapid thermal processing was applied to anneal the thin films for 5 min at 600 °C, 650 °C, and 700 °C under N2 (99.995%) atmosphere, causing the Ta2N and TaN crystalline phase formation. Al in Ta–N–Al was observed to hinder Ta2N and TaN crystalline phase formation during annealing. It is crucial to dope Al ith Ta–N appropriately to obtain a near-zero temperature coefficient of resistance (TCR) after annealing. The TCR of Ta–N–Al thin film, sputtered by TaAl (Al 20 at.%) alloy, was substantially affected by the annealing temperature. However, the thin film sputtered by TaAl (Al 10 at.%) alloy under 16% N2/Ar can achieve a TCR of −1.8 ppm/°C and 1.4 ppm/°C after annealing at 600 °C and 650 °C, respectively.

Wear and corrosion characteristics of nano-crystalline tantalum nitride coatings deposited on CoCrMo alloy for hip joint applications

Osteolysis is the resorption or removal of bone tissue, which is associated with the accumulation of polyethylene particles and misalignment of hip joint implant components. The mechanical properties, adhesion, tribological, and corrosive properties of single-layered tantalum nitride (TaN) coatings on biomedical grade cobalt alloy were evaluated to determine the potential of these coatings to prevent osteolysis in hip joint replacement applications. The TaN coatings were deposited directly on biomedical grade CoCrMo alloy disks using a hybrid system of Plasma Enhanced Chemical Vapor Deposition (PECVD) and Physical Vapor Deposition (PVD) at different deposition temperatures. By increasing the deposition temperature from 350 °C to 500 °C, the mechanical properties and adhesion improved remarkably, without a significant change in the crystal structure according to XRD and XPS results. The ball-on-disk wear testing results showed that the wear rate of the polyethylene balls decreased by 5% when sliding against the TaN-500C sample compared to sliding against the uncoated alloy and was 23% lower than the TaN-350C sample. The electrochemical corrosion results indicated that the TaN coating deposited at 500 °C is about 15% more noble than the uncoated alloy, which allows the rapid formation of a protective passive layer. These results suggest that TaN is a promising coating for CoCrMo alloy to improve the lifetime of hip joint implants.

Properties of plasma enhanced atomic layer deposited ruthenium thin films from Ru(EtCp)2

Ruthenium thin films were deposited by plasma enhanced atomic layer deposition using bis(ethylcyclopentadienyl)ruthenium(II) or Ru(EtCp)2 and oxygen plasma. The growth characteristics have been studied on a silicon substrate with different interfaces in a wide temperature range. On Si and SiO2, a nucleation delay period has been observed, which can be substantially reduced by the use of a tantalum nitride underlayer of ∼ 0.3 nm. The surface analysis shows that the substrate’s temperature strongly affects the composition of the film from ruthenium oxide at low temperatures to pure ruthenium film at higher temperatures.

Controlled multilevel switching and artificial synapse characteristics in transparent HfAlO-alloy based memristor with embedded TaN nanoparticles

• Transparent synaptic RRAM device with ALD based TaN-NPs was fabricated. • Stable conductive filaments formation by HfALO/TaO x N y interface has been studied. • Volatile threshold switching behavior achieved and current relaxation analyzed. • Controlled modulation of conductance with repeatable potentiation/depression achieved. Atomic layer deposition technique has been used to prepare tantalum nitride nanoparticles (TaN-NPs) and sandwiched between Al-doped HfO 2 layers to achieve ITO/HfAlO/TaN-NP/HfAlO/ITO RRAM device. Transmission electron microscopy along with energy dispersive spectroscopy confirms the presence of TaN-NPs. X-ray photoelectron spectroscopy suggests that part of TaN converted to tantalum oxynitride (TaO x N y ) which plays an important role in stable cycle-to-cycle resistive switching. Charge trapping and oxygen vacancy creation were found to be modified after the inclusion of TaN-NPs inside RRAM structure. Also, HfAlO/TaO x N y interface due to the presence TaN-NPs improves the device-to-device switching reliability by reducing the probability of random rupture/formation of conductive filaments (CFs). DC endurance of more than 10 3 cycles and memory data retention up to 10 4 s was achieved with an insignificant variation of different resistance states. Multilevel conductance was attained by controlling RESET voltage with stable data retention in multiple states. The volatile threshold switching was monitored after controlling the CF forming at 200 nA current compliance with high selectivity of ~10 3 . Synaptic learning behavior has been demonstrated by spike-rate-dependent plasticity (SRDP). Reliable potentiation and depression processes were observed after the application of suitable negative and positive pulses which shows the capability of the TaN NPs based RRAM device for transparent synaptic devices.

Investigation of reactively sputtered TaN thin-film resistors
 for microwave photonic applications

Electrophysical characteristics and their thermal stability of thin-film resistors based on tantalum nitride (TaN) obtained by reactive magnetron sputtering were investigated. The optimal modes of the magnetron sputtering process are determined, ensuring the Ta2N phase film composition with the value of the specific electrical resistance of 250 μm cm and high thermal stability of the parameters. On the basis of the investigations carried out, thin-film matching resistors were manufactured for use as part of an electro-optical InP-based MZ modulator

Structural engineering of transition-metal nitrides for surface-enhanced Raman scattering chips

Noble-metal-free surface-enhanced Raman scattering (SERS) substrates have attracted great attention for their abundant sources, good signal uniformity, superior biocompatibility, and high chemical stability. However, the lack of controllable synthesis and fabrication of noble-metal-free substrates with high SERS activity impedes their practical applications. Herein,we propose a general strategy to fabricate a series of planar transition-metal nitride (TMN) SERS chips via an ambient temperature sputtering deposition route.These planar TMN (tungsten nitride, tantalum nitride, and molybdenum nitride) chips show remarkable Raman enhancement factors (EFs) with ~105 owing to efficient photoinduced charge transfer process between TMN chips and probe molecules. Further, structural engineering of these TMN chips is used to improve their SERS activity. Benefiting from the synergistic effect of charge transfer process and electric field enhancement by constructing nanocavity structure, the Raman EF of WN nanocavity chips could be greatly improved to 1.29 * 107, which is an order of magnitude higher than that of planar chips. Moreover, we also design the WN/monolayer MoS2 heterostructure chips. With the increase of surface electron density on the upper WN and more exciton resonance transitions in the heterostructure, a 1.94 * 107 level EF and a 5 * 10-10 m level detention limit could be achieved. Our results provide important guidance for the structural design of ultrasensitive noble-metal-free SERS chips.

Ultrathin Cobalt Oxide Interlayer Facilitated Hole Storage for Sustained Water Oxidation over Composited Tantalum Nitride Photoanodes

The hole-storage layer (HSL) strategy has been demonstrated as an efficient interfacial modification method to overcome the instability of tantalum nitride (Ta3N5) photoanodes and further boost high performance in photoelectrochemical (PEC) water oxidation reaction. Herein, we report that the CoOx/Ni(OH)x bilayer as a typical HSL could effectively extract and store photogenerated holes from Ta3N5, resulting in a decent photocurrent enhancement and stable water oxidation for at least 30 h. Most strikingly, the reversible formation of Co(IV) species inside the ultrathin CoOx layer during PEC water oxidation is found to regulate the hole-storage process, leading to facilitated photogenerated hole extraction capacity and suppressed charge recombination. Furthermore, upon the insertion of the CoOx/Ni(OH)x bilayer for the Ta3N5/CoPi photoanode, the photocurrent could be evidently increased, emphasizing the general applicability of the HSL strategy in promoting water oxidation reaction.

Effect of Nitrogen Flow Ratio on Degradation Behaviors and Failure of Magnetron Sputter Deposited Tantalum Nitride

A series of Tantalum Nitride (TaN) films under a reactive direct current magnetron sputtering method with a controlled total gas flow rate were prepared on aluminum oxide substrates. To find the nitrogen flow rate, which produced the minimum sheet resistance, TaN films deposited under a nitrogen gas flow ratio of 2.5%, 5%, 10%, 15%, 20%, 25% were characterized in terms of their structural and electrical properties. The optimum total gas flow rate was 60 sccm, revealing the lowest deviation of sheet resistance. Next, the durability and reliability at high temperatures, after heating and cooling cycles and exposure to the induced current, were tested. When the nitrogen flow ratio reaches 2.5%, it gets the maximum for the adhesion force, roughness, and deposition rate of the TaN film, and maximum values are 75.4 N, 1.1 nm, and 3.67 nm/min, respectively, and the sheet resistance of the TaN film reaches a minimum of 20.32 Ω/sq. The degradation behaviors and failure of TaN films were investigated by measuring the sheet resistance variation. To further explain the degradation of TaN films, additional analysis of their crystallinity was conducted. The results showed that TaN-based thin film resistors have high durability and reliability, and are suitable for embedded passive resistors.

Nanomechanical and Nanotribological Properties of Nanostructured Coatings of Tantalum and Its Compounds on Steel Substrates.

The present paper addresses the problem of identification of microstructural, nanomechanical, and tribological properties of thin films of tantalum (Ta) and its compounds deposited on stainless steel substrates by direct current magnetron sputtering. The compositions of the obtained nanostructured films were determined by energy dispersive spectroscopy. Surface morphology was investigated using atomic force microscopy (AFM). The coatings were found to be homogeneous and have low roughness values (<10 nm). The values of microhardness and elastic modulus were obtained by means of nanoindentation. Elastic modulus values for all the coatings remained unchanged with different atomic percentage of tantalum in the films. The values of microhardness of the tantalum films were increased after incorporation of the oxygen and nitrogen atoms into the crystal lattice of the coatings. The coefficient of friction, CoF, was determined by the AFM method in the “sliding” and “plowing” modes. Deposition of the coatings on the substrates led to a decrease of CoF for the coating-substrate system compared to the substrates; thus, the final product utilizing such a coating will presumably have a longer service life. The tantalum nitride films were characterized by the smallest values of CoF and specific volumetric wear.

Comparison of surface properties, cell behaviors, bone regeneration and osseointegration between nano tantalum/PEEK composite and nano silicon nitride/PEEK composite

Both tantalum (Ta) and silicon nitride (SN) exhibit osteogenic bioactivity and antibacterial property. In addition, as a biomaterial for bone repair, polyetheretherketone (PEEK) has outstanding biocompatibility and mechanical performances while it is biologically inert. In this study, by blending PEEK with Ta and SN nanoparticles, respectively, Ta/PEEK composite (TPC) and SN/PEEK composite (SPC) were fabricated for load-bearing bone repair. The surface roughness, hydrophilicity and surface energy of TPC containing Ta nanoparticles were higher than SPC containing SN nanoparticles and PEEK. In addition, TPC with Ta nanoparticles exhibited low antibacterial property while SPC with SN nanoparticles showed high bacterial property. Moreover, the MC3T3-E1 cells responses (e.g. proliferation and differentiation) to TPC was the highest while PEEK was the lowest in vitro. Furthermore, new bone formation and osseointegration for TPC was the highest while PEEK was the lowest in vivo. In conclusion, compared with PEEK, addition of Ta and SN nanoparticles into PEEK fabricated bioactive composites of TPC and SPC with optimized surface property, which played crucial roles in inducing cellular response/bone regeneration. Although the osteogenic activity of SPC was lower than TPC, SPC exhibited osteogenic activity and good antibacterial property, which could prevent infection from bacterial. Therefore, SPC would have better potential for bone substitute.

Allotropic strengthening and in situ phase transformations during ultra-high-temperature flexure of bulk tantalum nitride

TaN samples were prepared using the spark plasma sintering at 1800 °C. Samples consisted of cubic tantalum nitride with the lattice parameter of a = 4.338 Å. The formation of hexagonal and cubic (a = 4.44 Å) TaN phases in situ during the flexural tests was analyzed using X-ray diffraction.