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Memristive devices are promising candidates for synaptic memories in neuromorphic computing systems, but the insufficient reliability of the analog behavior has been a challenge. Lateral oxide scaling with bottom-up technologies such as thermal oxidation, coupled with new device architectures, can improve the reliability. However, the effect of thermal oxide growth on analog device behavior remains unclear. In this study, we fabricate a variety of resistive switching thermal oxides on tantalum electrode surfaces and develop a method for rapid full factorial electrical analysis. The analysis uses 2500 unique control parameter combinations of current limits and RESET-stop-voltages to compare device behavior across millions of modulated current–voltage sweeps. We clarify the mechanisms that shift the device behavior from abrupt towards gradual SET transitions, a desirable characteristic for emulating analog plasticity. We found that a mildly negative differential resistance and an increased internal series resistance at the metal–oxide interface contribute to the stabilization of the gradual SET transitions. These findings highlight the importance of fine-tuning the bottom-up oxide growth for improving switching performance. [ABSTRACT FROM AUTHOR]

Herein, a localized surface plasmon resonance‐based sensor for volatile organic compounds (VOCs) detection is developed. The sensors are fabricated as a hybrid nanostructure of gold nanoparticles coated with a tantalum oxide (TaO) thin film on a glass slide substrate through magnetron sputtering and thermal solid‐state dewetting techniques. The thickness of the TaO film varies between 10 and 70 nm. The optical properties of samples are characterized by UV‐Vis‐NIR spectrophotometry, while their morphologies are confirmed via transmission electron microscopy. The results show the shift of the minimum optical transmittance related to the TaO thickness. Electrical field simulations are performed to predict the sensitivity of the prepared samples for VOCs detection. In addition, the sensors are tested with different VOCs, including formaldehyde, isopropanol, acetone, and methanol, which show good potential for practical applications. [ABSTRACT FROM AUTHOR]

In this study, we investigated the humidity sensing properties of TiO2-based ceramics doped with tantalum pentoxide (Ta2O5) and indium tin oxide (ITO). Pure TiO2, 1%Ta-doped TiO2 (1%TTO), 1%ITO-doped TiO2 (1%ISTO), and 1%(Ta2O5 + ITO) co-doped TiO2 (1%ISTTO) ceramic samples were obtained by sintering at 1200 °C for 3 h. The rutile phase was observed in all samples. The lattice parameters of the single and co-doped samples were larger than those of pure TiO2, confirming the substitution of dopants. Porosity was observed in all ceramics. The mean grain sizes of all doped samples were significantly reduced compared to undoped TiO2. A homogeneous element dispersion was observed in the 1%TTO and 1%ISTTO ceramics, while segregation particles of related In-rich elements was observed in the 1%ISTO ceramic. Giant dielectric properties were not achieved in any samples due to the porosity. Nevertheless, excluding the undoped TiO2, the dielectric properties of all porous ceramics varied significantly with changes in humidity. The 1%ISTTO ceramic demonstrated superior humidity sensing properties, including a low maximum hysteresis error of 3.6% at 102 Hz. In contrast, the 1% TTO and 1% ISTO ceramics showed higher maximum hysteresis errors of 7.2% and 19.8%, respectively. Notably, the response and recovery times were 7.05 ± 0.18 and 2.48 ± 0.39 min, respectively, with good repeatability. This improvement is likely due to the synergistic effect of oxygen vacancies and Ta Ti · defects on the surface, enhancing the humidity sensing properties of the 1% ISTTO ceramic, coupled with its optimal microstructure due to its lowest porosity and grain size. [ABSTRACT FROM AUTHOR]

The visible and near‐infrared (NIR) electroluminescence (EL) from the light‐emitting device (LED) based on the erbium (Er)‐doped Ta2O5 (Ta2O5:Er)/SiO2/Si structure is reported in this study. Wherein, an ≈10 nm thick SiO2 intermediate layer serves as an energy plateau for forming hot electrons, which initially transport from Si via trap‐assisted tunneling mechanism under sufficiently forward bias with the negative voltage connecting with Si. The hot electrons impact‐excite the Er3+ ions incorporated into the Ta2O5 host, leading to the Er‐related EL from the aforementioned LED. It is found that the 750 °Cannealed Ta2O5:Er films are desirable to act as the light‐emitting component. Despite that the Er‐related photoluminescence from the Ta2O5:Er film becomes stronger in turn with the Er‐doping content increasing from nominal 0.75, 1.5 to 3 mol%, it is the Ta2O5:Er film with Er‐doping content of nominal 1.5 mol% rather than 3 mol% that enables the LED to exhibit the strongest EL. Based on the EL lifetime measurement and the structural characterizations, it is believed that the enhanced non‐radiative interactions among the Er3+ ions and the substantial amorphousness of Ta2O5 host caused by the nominal 3 mol% Er‐doping are responsible for the weakened EL as mentioned above. [ABSTRACT FROM AUTHOR]

The hot corrosion resistance of 8 wt.% yttria‐stabilized zirconia (8YSZ) powder, modified with CaO, MgO, Ta2O5, and TiO2 at concentrations of 5, 10, and 15 wt.%, was systematically investigated in a molten vanadium pentoxide (V2O5) environment at 900°C and 1100°C for 48 h. The modified 8YSZ samples, coated with V2O5, underwent thermal cycling totaling 12 cycles. Results revealed susceptibility to hot corrosion for all doped 8YSZ powders, attributed to tetragonal ZrO2 destabilization, forming monoclinic ZrO2. Remarkably, 8YSZ/CaO demonstrated exceptional resistance to hot corrosion when exposed to a temperature of 900°C. The corrosion product found in the 8YSZ/Ta2O5 material was determined to be tetragonal Zr0.66Y0.17Ta0.17O2. Although, 8YSZ/TiO2 undergoes deterioration at 900°C, it exhibits improved resistance at 1100°C, resulting in the formation of TiVO4. [ABSTRACT FROM AUTHOR]

Electrolytic capacitors are known to be fast devices with very low time constant and able to deliver high power. This class of capacitors is then an interesting technology to power miniaturized embedded electronics for Internet of Things applications. However, the current electrolytic capacitor suffers from its bulky size that does not fit with the miniaturization. To solve this issue, a proof‐of‐concept consisting of miniaturizing an electrolytic capacitor based on tantalum materials to give rise to a new class of electrolytic micro‐capacitors is proposed. To reach this ambitious objective, thin films (<100 nm) of tantalum metal (Ta), tantalum nitride (TaN), and tantalum oxide (Ta2O5) are deposited on a Si substrate by sputtering deposition method. After a careful optimization of the deposition parameters, Ta/Ta2O5 and TaN/Ta2O5 electrodes (Ta and TaN ≈45 nm and Ta2O5 ≈25 nm) and study their behaviors when biased at high voltage (>20 Volts) in aqueous electrolyte are produced. The Ta/Ta2O5 and TaN/Ta2O5 interfaces when the electrode is polarized near and beyond the breakdown voltage of the dielectric layer are carefully investigated. Polarizing the electrodes beyond the breakdown voltage are shown to result in anodization‐like mechanisms. In the case of the TaN/Ta2O5 electrode, an N‐rich porous layer grew within the Ta2O5 layer as polarization increased. A comparative study on the 2 stacked layers electrodes with different compositions (Ta/Ta2O5 and TaN/Ta2O5) but similar thicknesses (45/25 nm) is carried out: both electrodes show excellent capacitance retention of over 90% over 300 000 cycles. The frequency behavior of Ta/Ta2O5 and TaN/Ta2O5 electrodes shows that both are potential candidates in electrolytic micro‐capacitors for powering miniaturized electronics. [ABSTRACT FROM AUTHOR]

Ti/IrO2-Ta2O5 electrodes are extensively utilized in the electrochemical industries such as copper foil production, cathodic protection, and wastewater treatment. However, their performance degrades rapidly under high current densities and severe oxygen evolution conditions. To address this issue, we have developed a composite anode of Ti/Ta-Ti/IrO2-Ta2O5 with a Ta-Ti alloy interlayer deposited on a Ti substrate by double-glow plasma surface alloying, and the IrO2-Ta2O5 surface coating prepared by the traditional thermal decomposition method. This investigation indicates that the electrode with Ta-Ti alloy interlayer reduces the agglomerates of precipitated IrO2 nanoparticles and refines the grain size of IrO2, thereby increasing the number of active sites and enhancing the electrocatalytic activity. Accelerated lifetime tests demonstrate that the Ti/Ta-Ti/IrO2-Ta2O5 electrode exhibits a much higher stability than the Ti/IrO2-Ta2O5 electrode. The significant improvement in electrochemical stability is attributed to the Ta-Ti interlayer, which offers high corrosion resistance and effective protection for the titanium substrate. [ABSTRACT FROM AUTHOR]

In the present study, capacitance–voltage and triangular voltage sweep (TVS) measurements reveal mobile positively charged defects in both Ta2O5 and Nb2O5 layers deposited on thin SiO2 layers . These defects are not detected in the SiO2 layers before the deposition of high‐k oxides and their concentration depends significantly on the purity of the targets. The electrical properties of these defects are found to be similar to those of positively charged Na+ in SiO2. Vapor‐phase decomposition‐inductively coupled plasma‐mass spectrometry (VPD‐ICPMS) measurements show that Na is a dominant signal besides Ta and Nb after the deposition of Ta2O5 and Nb2O5, respectively. Considering these findings, the origin of the positively charged defects is discussed with an emphasis on their correlation with Na+. [ABSTRACT FROM AUTHOR]

A dual S‐scheme heterojunction of Ta3N5/Bi2O2CO3/Ta2O5 was synthesized with enhanced photoactivity for MB degradation. The Ta3N5 modification introduces hierarchical pore structures in composite, which is conducive to dye absorption and degradation. Ta3N5 also enhances the light harvesting capability and improves the carrier separation and transfer efficiency of composite due to its superior photoelectrical properties. A S‐scheme heterojunction was proved to be formed between Ta3N5 and Bi2O2CO3, which not only accelerates the carrier separation and transfer efficiency, but also preserves electrons and holes with superior redox capability in composite. Thus, the formation of ⋅O2− and ⋅OH with superior oxidation capability were significantly enhanced in Ta3N5/Bi2O2CO3 composite. MB (20 mg/L) degradation efficiency was enhanced from 55 % of Ta3N5 and Bi2O2CO3 in 3 hours to almost 95 % of Ta3N5/Bi2O2CO3 composite. Because Ta3N5 was partly oxidized to Ta2O5 during preparation, a dual S‐scheme heterojunction of Ta3N5/Bi2O2CO3/Ta2O5 was proposed, which provided an exemplary way of fabricating dual S‐scheme heterojunction involving Ta3N5 and Ta2O5. [ABSTRACT FROM AUTHOR]

CO oxidation at mild condition is significant for industrial process but still challenging nowadays, especially for the non-noble metal catalysts. The preparation method significant affect the catalytic activity of the catalyst. Comparing with cobalt supported on tantalum oxide prepared by impregnation method, Co/Ta2O5 prepared by deposition–precipitation method with urea in this study has smaller particle size, higher specific surface area and better redox properties, and these features make the catalyst exhibit higher catalytic activity for CO oxidation at mild condition. 90% CO conversion was achieved at 130 ℃, and CO was fully converted at 150 ℃. The XPS and DRIFTs results show that Co/Ta2O5 has more oxygen vacancies, and the absorbed CO will react with oxygen. The study may provide a new thought for the preparation of catalysts with high activity at mild condition. [ABSTRACT FROM AUTHOR]

Unique Pt/TaO x /MC cathode electrocatalysts for polymer electrolyte fuel cells (PEFCs) are developed using partially-reduced TaO x decorated on mesoporous carbon (MC). An initial mass activity (MA) of more than 500 A g−1 was observed for a TaO x /MC support heat treated at 700 °C in H 2 or 1300 °C in Ar, more than double that of a conventional Pt/C electrocatalyst. The durability against start-stop and load potential cycling was successfully improved compared with the reference catalysts, as verified by half-cell voltammetry and full membrane-electrode-assembly (MEA) tests. Durability against start-stop cycling was attributed to the use of a thermochemically-stable TaO x support which prevents direct contact between Pt and MC, thus minimizing carbon corrosion. Durability against load cycling was mainly attributed to the mesoporous structure, preventing the agglomeration of Pt catalyst particles. As such, the Pt/TaO x /MC cathode electrocatalysts presented in this work have the potential to achieve both high durability and high power output, which is especially attractive for heavy-duty vehicular fuel cell applications. • Pt/TaO x /MC electrocatalysts are prepared with nanocrystalline TaO x on MC. • Mass activity of the electrocatalysts treated in H 2 and Ar exceeds 500 A g−1. • The Pt/TaO x /MC cells display sufficient current-voltage characteristics. • The Pt/TaO x /MC cells exhibit improved start-stop and load cycle durability. [ABSTRACT FROM AUTHOR]

Resistive Random-Access Memory (RRAM) presents a transformative technology for diverse computing and artificial intelligence applications. However, variability in the high resistance state (HRS) has proved to be a challenge, impeding its widespread adoption. This study focuses on optimizing TaOx -based RRAMs by strategically placing a nitrogen-doped TaOx barrier-layer (BL) to mitigate variability in the HRS. Through comprehensive electrical characterization and measurements, we uncover the critical influence of BL positioning on HRS variability and identify the optimal location of the BL to achieve a 2x lowering of HRS variability as well as an expanded range of operating voltages. Incremental reset pulse amplitude measurements show that the TaOx :N maintains a low HRS variability even at higher operating voltages when the position of the BL is optimized. Our findings offer insights into stable and reliable RRAM operation, highlighting the potential of the proposed BL to enhance the functionality of TaOx -based RRAMs and elevate overall device performance. [ABSTRACT FROM AUTHOR]

Anomaly detection, a data intensive task, is very important in wide application scenarios. Memristor has shown excellent performance in data intensive tasks. However, memristor used for anomaly detection has rarely been reported. In this Letter, a tantalum oxide (TaOx) memristive neuron device has been developed for anomaly detection application. TaOx, a CMOS compatible material, based memristor shows reliable threshold switching characteristics, which is suitable for constructing memristive neuron. Furthermore, the output frequency of the memristive neuron is found to be proportionate to the applied stimulus intensity and at an inflection point starts to decrease, namely, thresholding effect. Based on the thresholding effect of the neuron output, the application of the memristive neuron for anomaly detection has been simulated. The results indicate that the TaOx memristive neuron with thresholding effect shows better performance (98.78%) than the neuron without threshoding effect (90.89%) for anomaly detection task. This work provided an effective idea for developing memristive anomaly detection system. [ABSTRACT FROM AUTHOR]

• Coatings with Ta 2 O 5 nanoparticles were successfully formed on Mg. • It was found that incorporation of Ta 2 O 5 nanoparticles increases roughness and porosity of the PEO layers contributing into sufficient soft tissue ingrowth in vivo. • The cell morphology indicates good histocompatibility of the obtained coatings and intensive tissue ingrowth. • It was found that incorporation of the Ta 2 O 5 nanoparticles elicits higher rates of apatite layer formation. The present study investigates the physical and chemical characteristics, behavior in vitro and in vivo , and biocompatibility of coatings containing Ta 2 O 5 , which are obtained by plasma electrolytic oxidation (PEO) on MA8 magnesium alloy. The obtained coatings demonstrate in vivo biocompatibility and in vitro bioactivity. Compared to the base PEO coating, the layers containing Ta 2 O 5 facilitate the development of apatite in simulated body fluid, suggesting that the inclusion of nanoparticles improves bioactivity of the coatings. It was found that incorporation of Ta 2 O 5 nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in vivo. Based on in vivo studies, these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen evolution. The results obtained in the present study concluded biocompatibility, tissue integration of the PEO coatings containing Ta 2 O 5 nanoparticles making them a promising protective layer for biodegradable magnesium implants. [Display omitted] [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) is a very sensitive technique for keeping track of changes in the optical properties close to the sensor surface. In the Kretschmann configuration, it can be triggered by an evanescent field resulting from total internal reflection from the rear of the sensor surface. The layers were deposited on the semicircular glass prism LASF35 using toluene (C7H8) as a sensing medium. The simulation model was created at a sodium (Na) layer thickness of (dNa) (dNa = 50 nm) layers and at varying thicknesses of tantalum pentoxide (Ta2O5) (dTa2O5).The parameters of the surface plasmon resonance angle (SPR) were computed. SPR occurred strongly and well in the IR area at (800, 900) nm when it was not seen in the ultraviolet region (100 nm) and appeared in the visible region at 500, 600, and 700 nm. The visible region's highest sensitivity (S = 190) occurred at 700 nm, where the sodium layer thickness (dNa) values of SPR dip length (Ld) and full width half maximum (FWHM) were excellent (50 nm). As a result, the suggested sensor can operate at wavelengths of 500, 600, 700, 800, and 900 nm in the IR-visible range. [ABSTRACT FROM AUTHOR]

In this study, we fabricated limiting current‐type oxygen microsensors capable of sensing a wide range of oxygen concentrations. The oxygen microsensors consist of yttria‐stabilized zirconia thin films on spiral Ta2O5 diffusion layers and high‐temperature micro‐hotplates. At temperatures above 575 °C, we observed a clear limiting current that increased proportionally with oxygen concentration between 0.4% and 94%. This wide‐range linearity is attributed to the Knudsen diffusion of the oxygen gas passing through the small gap in the spiral Ta2O5 diffusion layer. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A mid-infrared to terahertz ultra-broadband all-dielectric absorber is proposed and numerically verified, which consists of a single medium of tantalum pentoxide (Ta2O5) with pyramid arrays on a film substrate. Absorption is higher than 0.9 between 0.72 and 100 THz with a bandwidth of 99.28 THz and a relative bandwidth of 197%. It is higher than 0.9999 between 2 and 100 THz. The ultra-broadband absorption in 0.72~100 THz results from the particular permittivity of Ta2O5 and the optimized structure. The inner mechanism is studied by the spectra and impedance match of different parts of the structure and the distributions of electromagnetic fields and loss at different frequencies. Furthermore, the ultra-broadband perfect absorber is insensitive to polarization angle, incident angle, structure parameters as well as structure shape. These characteristics make the proposed absorber more practical in mid-infrared to terahertz ultra-broadband stealth, imaging and thermal emission. [ABSTRACT FROM AUTHOR]

We present a transmon qubit fabrication technique that yields systematic improvements in T1 relaxation times. We encapsulate the surface of niobium and prevent the formation of its lossy surface oxide. By maintaining the same superconducting metal and only varying the surface, this comparative investigation examining different capping materials, such as tantalum, aluminum, titanium nitride, and gold, as well as substrates across different qubit foundries demonstrates the detrimental impact that niobium oxides have on coherence times of superconducting qubits, compared to native oxides of tantalum, aluminum or titanium nitride. Our surface-encapsulated niobium qubit devices exhibit T1 relaxation times 2–5 times longer than baseline qubit devices with native niobium oxides. When capping niobium with tantalum, we obtain median qubit lifetimes above 300 μs, with maximum values up to 600 μs. Our comparative structural and chemical analysis provides insight into why amorphous niobium oxides may induce higher losses compared to other amorphous oxides. [ABSTRACT FROM AUTHOR]

Resistive switching devices based on metal oxides are candidates for nonvolatile memory storage. They often rely on the valence change mechanism, the field‐induced movement of donor ions leading to nanoscale conductive paths in filamentary‐type devices. Devices usually consist of a transition metal oxide like Ta2O5 sandwiched between two metal electrodes. Critical parameters of the devices, such as cycle‐to‐cycle variability, Roff/Ron ratio, and endurance depend on the morphology and composition of the filaments. However, investigating filaments on the nanoscale is cumbersome, and commonly applied techniques such as conductive atomic force or transmission electron microscopy require delaminating the metal top electrode, inhibiting in operando investigations over many switching cycles. Here, the authors use infrared scattering‐type scanning near‐field optical microscopy (s‐SNOM) to investigate resistive switching in Ta2O5 films with a graphene top electrode in operando and reveal individual filaments on the device level. By selecting an appropriate illumination frequency, the authors can trace the evolution of filaments and the joule heating‐induced retraction of the top electrode until device failure. s‐SNOM promises a deeper understanding of resistive switching devices' microscopic switching behavior and applies to a wide range of resistive switching oxides, such as HfO2, SrTiO3, and SiO2. [ABSTRACT FROM AUTHOR]

The effect of Ta 2 O 5 at the rates of 1, 2, 3 and 4 % mol on the CaO–SrO–B 2 O 3 –Al 2 O 3 –Bi 2 O 3 –SiO 2 glass system was examined by the melt-quenching at 1400 °C. Non-isothermal crystallization kinetics of the compounds were calculated using Differential Scanning Calorimetry (DSC). The kinetics study revealed activation energy values of 109.4 kJ/mol for the T1 composition, 302.14 kJ/mol for the T2 composition, 471.5 kJ/mol for the T3 composition, and 344.7 kJ/mol for the T4 composition, as determined by applying the Kissinger method. According to the average of Avrami parameters, two-dimensional crystal growth was observed in T1 glass and surface crystallization was observed in all other glass. The glass forming ability (GFA) of the glasses was investigated with the values obtained as a result of HSM analysis. In the XRD analysis performed after heat treatment at 850 °C, crystal phase development was observed in the glasses. As a result of the crystallization process, it was observed that wollastonite, strontium aluminum silicate, strontium aluminum oxide and bismuth oxide phases were formed in T1, T2 and T3 glasses. [ABSTRACT FROM AUTHOR]

Co doped bismuth magnesium tantalate with a pyrochlore structure (sp. gr. Fd-3m) was synthesized for the first time using the standard ceramic method. Single phase Bi2Mg1−xCoxTa2O9 samples were found to be formed when x < 0.7 in the X-ray phase analysis. However, with a higher cobalt content in the samples, the impurity phase β-BiTaO4 (sp. gr. P-1) is detected, and its amount is proportional to the degree of cobalt doping. The formation of solid solutions is evidenced by a uniform increase in the unit cell parameter of the Co,Mg co doped bismuth tantalate phase with an increase in the content of cobalt ions in the samples from 10.5412(8) (x = 0.3) to 10.5499(8) Å (x = 0.7). The samples exhibit a porous microstructure consisting of chaotically oriented and partially fused elongated grains measuring 1–2 μm. The dependence of the ceramic grain size on the n(Mg)/n(Co) ratio was not determined. X-ray spectroscopy (ear dge X-ray bsorption ine tructure (NEXAFS) and X-ray photoelectron spectroscopy (XPS)) was used to study the charge state of ions in Bi2Mg1−xCoxTa2O9. The NEXAFS and XPS data showed that doping with cobalt and magnesium did not change the bismuth and tantalum oxidation states in pyrochlore; in particular, the ions maintained their oxidation states of Bi(+3), Mg(+2) and Ta(+5). The energy position of the peaks of the Ta4f-, Ta5p-, Ta4d spectra had a characteristic shift towards lower energies compared to the binding energy in pentavalent tantalum oxide Ta2O5. A shift towards lower energies is characteristic of a decrease in the effective positive charge; in particular, for the Ta4f and Ta4d spectra we presented, this energy shift was ΔE = 0.65 eV, and in the region of the Ta4d edge—0.55 eV. This in turn allowed for us to assume that tantalum atoms have the same effective charge +(5-δ). The oxidation state of cobalt ions was predominantly 2+ and partially 3+, according to NEXAFS spectroscopy data. [ABSTRACT FROM AUTHOR]

Tantalum oxide and tantalum oxynitride structures were examined through density functional theory using the trans-blaha-modified Becke–Johnson approximation and an experimental approach for the prediction of electronic, thermoelectric, and optical properties. Pure Ta2O5 and Ta2O5-xNx thin films were prepared using the well-known DC magnetron sputtering for comparative computational and experimental investigations. The thermoelectric properties were evaluated, and a considerable improvement in parameters was observed with an increase in dopant concentration. Phase identification and structural analysis of the thin films were performed using x-ray diffraction analysis. The optical band gap measured by the Tauc relationship showed a decrease in the band gap from 2.57 to 2.05 eV with the increase in nitrogen content which followed the simulation trend. The experimental investigation of the optical parameters of pure and N-doped Ta2O5 thin films was carried out. The simulation and experimental results depicted an epsilon near-zero response with maximum N doping (Ta2O1.25N3.75) in the visible and near-infrared regimes. The theoretical and experimental results showed nearly identical correlations. These thin films are considered suitable potential candidates for thermoelectric and optoelectronic applications due to their unique enhanced parameters. [ABSTRACT FROM AUTHOR]

Kesterite solar cells often suffer from low open‐circuit voltage due to interface recombination. To address this, a passivation approach is explored using a dielectric layer between the absorber and buffer layer, coupled with a point contact structure. In this method, carrier transport is enabled through point contacts while effectively passivating regions covered by oxide. In this study, although forming point contacts on the front surface poses processing challenges, a novel solution is presented. Herein, in situ formed ZnS nanoparticles (NPs) during Cu2ZnSn(S, Se)4 (CZTSSe) absorber fabrication is utilized as a nanomask for front surface point contacts. A thin TaOx layer, acting as the passivation layer, is deposited over the CZTSSe surface with ZnS NPs by using atomic layer deposition (ALD). The selective removal of these NPs by deionized water soaking creates size‐controlled point contacts without damaging the absorber surface. In this approach, the first successful implementation of TaOx in enhancing CZTSSe solar cell efficiency, which jumps from 6.17% to 9.02% due to this strategy, is marked. The passivation mechanism involves sodium attraction during ALD, reduced interface defects, and the generation of positive fixed oxide charges. In this innovative method, not only solar cell efficiency is improved but new insights are also provided into using secondary phases as nanomasks in interface engineering. [ABSTRACT FROM AUTHOR]

Background: Advancements in dentistry and incorporating 3D printing techniques have numerous benefits over traditional methods. However, the produced resins have shown a lack of good biocompatibility and insufficient mechanical properties. Tantalum oxide, on the other hand, exhibits biocompatibility, excellent physical and mechanical properties, and an antimicrobial effect. Aim of the study: To assess the tensile strength of tantalum oxide nanoparticles when used with 3D-printed denture-based resins before and after thermocycling. Materials and Methods: The materials tested in this study were laser-based stereolithography (an additive manufacturing process, SLA). Eighty samples were prepared from 3D-printed resin. The sample was divided into two groups (before and after thermocycling), and each group was subdivided into four subgroups. Results: There was a statistically significant association between the used concentrations when tested before and after thermocycling, with a high statistical significance (p-value = 0.001). Additionally, there was a high statistical significance for the concentration before thermocycling in relation to after thermocycling with (p-value 0.001). Conclusion: Using tantalum oxide improved the tensile strength of the 3D-printed resins by promoting characteristic osseointegration and enhancing its ability to promote osteoblast formation, proliferation, and integration into the bone. [ABSTRACT FROM AUTHOR]

The Magnetron sputtering method was utilized to apply tantalum-oxide coatings on NiTi shape memory alloys, and this was done under 16.6 vol% oxygen, 83.4 vol% argon atmospheres at a substrate temperature of 300 °C. In the present article, the influence of sputtering rate on surface morphology, roughness, corrosion behavior, and biological response of tantalum oxide coatings has been investigated via FESEM, AFM, potentiodynamic polarization method, and MTT assay, respectively. FESEM studies demonstrated the positive effect of sputtering rate on forming a uniform and dense layer under 0.8 Å s−1 sputtering rate. GI-XRD patterns depicted amorphous coatings in all samples, meaning 300 °C was not sufficient for the formation of crystallized TaxOy. The XPS results revealed that stoichiometric tantalum pentoxide formed at the top of the layer under 0.8 Å s−1 sputtering rate as there was enough oxygen to support the reaction. AFM 3D images of surface topographies suggested that all coatings possessed almost similar roughness values, but their line graphs showed irregular peaks and valleys for lower and higher sputtering rates. Electrochemical measurements indicated the expected results of supremacy in corrosion resistance for the sample sputtered under 0.8 Å s−1 with the most uniform morphology. Finally, the biocompatibility of the coatings was studied using specific human endothelial cells (HUVECs) to evaluate their potential for vascular applications. Unlike other results, the sample, which sputtered at the highest rate with lots of hills and valleys, showed the greatest cell viability and cellular activity on its surface.

The niobium oxide dihalides have recently been identified as a new class of van der Waals materials exhibiting exceptionally large second-order nonlinear optical responses and robust in-plane ferroelectricity. In contrast to second-order nonlinear processes, third-order optical nonlinearities can arise irrespective of whether a crystal lattice is centrosymmetric. Here, we report third harmonic generation (THG) in two-dimensional (2D) transition metal oxide iodides, namely NbOI2 and TaOI2. We observe a comparable THG intensity from both materials. By benchmarking against THG from monolayer WS2, we deduce that the third-order susceptibility is approximately on the same order. THG resonances are revealed at different excitation wavelengths, likely due to enhancement by excitonic states and band edge resonances. The THG intensity increases for material thicknesses up to 30 nm, owing to weak interlayer coupling. After this threshold, it shows saturation or a decrease, due to optical interference effects. Our results establish niobium and tantalum oxide iodides as promising 2D materials for third-order nonlinear optics, with intrinsic in-plane ferroelectricity and thickness-tunable nonlinear efficiency. [ABSTRACT FROM AUTHOR]

Low voltage oxide thin-film transistors (TFTs) operating below 1.0 V were developed using a high dielectric constant tantalum oxide produced by thermal oxidation. Thermal oxidation was carried out at 400, 500 and 600 °C under an oxygen atmosphere. The tantalum oxide was evaluated by X-ray photoelectron spectroscopy (XPS). XPS confirmed the binding energy of Ta4f, indicating the binding state of tantalum oxide. The bottom gate oxide TFT with the gate insulator of tantalum oxide grown at 500 °C exhibited mobility of 26.7 cm2/V s and a threshold voltage of 1.3 V. The transfer characteristics at the drain voltages below 1.0 V show its applicability to low voltage operation below 1 V. The bootstrapped inverter with developed oxide TFTs operated well at the 1.0 and 2.0 V operation voltages. [ABSTRACT FROM AUTHOR]

The presence of amorphous oxide layers can significantly affect the coherent time of superconducting qubits due to their high dielectric loss. Typically, the surface oxides of superconductor films exhibit lossy and unstable behavior when exposed to air. To increase the coherence time, it is essential for qubits to have stable and low dielectric loss oxides, either as barrier or passivation layers. In this study, we highlight the robust and stable nature of an amorphous tantalum oxide layer formed on α-Ta (110) film by employing chemical and structural analyses. Such kind of oxide layer forms in a self-limiting process on the surface of α-Ta (110) film in piranha solution, yielding stable thickness and steady chemical composition. Quarter-wavelength coplanar waveguide resonators are made to study the loss of this oxide. One resonator has a Qi of 3.0 × 106 in the single photon region. The Qi of most devices are higher than 2.0 × 106. Moreover, most of them are still over 1 × 106 even after exposed to air for months. Based on these findings, we propose an all-tantalum superconducting qubit utilizing such oxide as passivation layers, which possess low dielectric loss and improved stability. [ABSTRACT FROM AUTHOR]

In recent times, significant progress is made in the development of solar‐blind deep‐ultraviolet (DUV) photodetectors (200–280 nm) due to their potential applications for military and civil purposes. In this study, the development of a novel solar‐blind DUV photodetector based on tantalum pentoxide (Ta2O5) nanoparticles (NPs) utilizing Surface Acoustic Wave (SAW) sensor integrated with Interface electronics is reported for the first time. The 3‐D Ta2O5 NPs surface morphology, crystallinity, and defect state level is discussed using various analytical techniques, including scanning electron microscope (SEM), X‐ray diffraction (XRD), and spectrophotometer. The developed 3‐D Ta2O5 NPs based photodetector exhibits high sensitivity to 254 nm DUV irradiation (5 µW cm−2), demonstrating excellent photoresponse characteristics. The performance parameters including highest sensitivity, fast response/recovery time are measured as 1621.1 ppm (mW cm−2)−1, 3.7s/19.8s, respectively. Subsequent analysis demonstrates the stability and repeatability of the photodetector, enabling its potential to real time corona discharge detection. With its inherent advantages, the current DUV photodetector utilizing Ta2O5 NPs exhibits great potential for future applications in DUV optoelectronics. [ABSTRACT FROM AUTHOR]

The cycling and rate capabilities of LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode material under high cut‐off voltage (≥4.5 V) and high current density have attracted much attention. However, the material's insufficient intrinsic electronic/ion conductivity and interface instability are still key issues restricting its electrochemical performance.In this paper, a graphene/Ta2O5 co‐coating layer is successfully fabricated on the surface of NCM523 to form a cathode material of GTa‐NCM523 to enhance both the electron and lithium‐ion transport during cathode operation. The GTa‐NCM523 cathode material achieves a discharge specific capacity of 147.4 mAh g−1 after 600 cycles at a voltage of 3.0–4.5 V and a rate of 1 C (180 mA g−1) with a capacity retention rate of 81.4 %. In contrast, the uncoated NCM523 only retains 63.2 % of its capability. At an elevated rate of 10 C (1800 mA g−1), the GTa‐NCM523 can achieve a discharge‐specific capacity of up to 113.5 mAh g−1, which is 43.7 % higher than the uncoated NCM523. The co‐coating layer can inhibit HF erosion and accelerate the movement of lithium‐ions and electrons, which account for the superior electrochemical characteristics of the co‐coating layer comprised of graphene and Ta2O5. [ABSTRACT FROM AUTHOR]

We investigated the morphology and phase composition of tantalum diboride (TaB2) oxidation products by oxygen in the air across a temperature range of 20 to 1000°C. At isothermal conditions of 450, 500, 550, and 600°C, we determined the oxidation rate constants for TaB2 nanoparticles with an average particle diameter of ~70 nm (0.0006, 0.0027, 0.009, and 0.015 s–1, respectively). The apparent activation energy for the oxidation reaction of TaB2 nanoparticles, derived from the temperature dependence of the rate constants, was estimated to be 115 ± 6 kJ/mol. [ABSTRACT FROM AUTHOR]

The results of studying the processes of formation of silicon oxide nanolayers by the method of molecular layering (atomic layer deposition) on the surface of films of tantalum and niobium oxides obtained by electrochemical oxidation of the corresponding metals are presented. Studying the electrical strength of metal-dielectric-metal (MDM) structures based on tantalum and niobium oxides shows that the introduction of an additive dielectric layer (SiO2) allows us to significantly increase the electrical strength of these structures. [ABSTRACT FROM AUTHOR]

Glass samples belonging the TeO 2 - Ta 2 O 5 - Bi 2 O 3 (TTB) system are prepared by conventional melt-quenching technique and the corresponding vitreous domain is identified. A crystallization study of the 80 TeO 2 - 10 Ta 2 O 5 - 10 Bi 2 O 3 glass composition versus temperature shows structural transitions from glass to the stabilization of an unreported translucent anti-glass phase and eventually to a fully transparent crystalline ceramic in both the visible and infrared ranges. The structure and microstructure of the anti-glass and ceramic phases are characterized by Powder X-Ray Diffraction, Electron Back-Scatter Diffraction, Transmission Electron Microscopy and Raman spectroscopy. The optical properties of undoped and Er3+-doped transparent samples are also discussed. Up-conversion green emission band shows that the glass intensity is about 2 and 4 times more intense than that of the anti-glass and the ceramic, respectively. Furthermore, a large spectral bandwidth of 105 nm is found in the anti-glass sample. The advantageous spectroscopic characteristics found here, together with the good thermal stability of these samples, suggest that the anti-glass phase has potential applications as amplification medium for the generation of ultrashort (femtoseconds) pulses. [ABSTRACT FROM AUTHOR]

This paper presents a performance analysis of indium-gallium-zinc-oxide (IGZO)- and pentacene-based top-gate-top-contact (TGTC) and bottom-gate-top-contact (BGTC) thin film transistors (TFTs). Extensive simulation has been performed to assess the performances in terms of threshold voltage, subthreshold slope, on-off current ratio, mobility, and figure of merit (FoM). Results indicate a trade-off between mobility and current ratio with respect to the permittivity of the dielectric layer, where tantalum oxide (Ta2O 5) provides the optimum result in terms of FoM. The mobility of IGZO is significantly higher for both structures, whereas the current ratio for IGZO is higher than pentacene in the BGTC configuration. Comparing the structural configurations, Ta2O5-IGZO-based BGTC achieves 5. 9 2 × and 4 1. 8 × better mobility and current ratio, respectively, over TGTC structures. The threshold voltage of IGZO-based TFT is observed to increase with the permittivity of the dielectric in TGTC configuration but decrease in BGTC configuration. Meanwhile, the increase in oxide and active layer thicknesses causes a decrease in the threshold voltage. Moreover, both mobility and current ratio improve with a decrease in oxide or active layer thickness. Maximum mobility of 32.30 cm2/Vs and a maximum current ratio of 7.54E+08 are achieved for Ta2O5-IGZO-based BGTC TFT with 10 μ m channel thickness and 5 μ m oxide thickness. [ABSTRACT FROM AUTHOR]

Although a high permittivity (ε′>104) of rutile TiO 2 can easily be obtained by doping with Ta5+, the low loss tangent (tanδ<0.05) cannot be achieved. Furthermore, ε′ of giant dielectric oxides is usually dependent on environmental factors (temperature and humidity) and operation factors (frequency and DC bias). In this study, greatly reduced tanδ and enhanced ε′–stabilities were obtained in TiO 2 by doping with Ta 2 O 5 and indium tin oxides (ISO). Dense ceramics with homogeneously dispersion of doping elements were obtained by sintering at 1400 °C for 3 h. The rutile phase was detected with expanded lattice parameters as ISO increased, while the average grain size decreased slightly with a narrow size distribution. According to the Raman spectroscopy, oxygen vacancies in Ta 2 O 5 –doped TiO 2 tended to slightly increase by doping with ISO. Besides a high ε′ of ∼2–4 × 104, low tanδ values of 0.007–0.04 (103 Hz) were achieved in the temperature range of −80 to 200 °C. The temperature coefficient of ε′ at 1 kHz from −120 to 200 °C was lower than ±10% compared to that of 25 °C. Furthermore, the ε′ was also nearly independent on the DC bias even at 300 V/cm (∼2.6%). Surprisingly, the ε′ was nearly independent on humidity over the range of 25–90%RH. Thereas, this giant dielectric material may have a great potential for capacitor applications. Impedance and dielectric spectroscopies revealed that the giant dielectric properties were caused by the interfacial polarization, while the effect of defect dipoles cannot be ignored, which could have a primary contribution in a low–temperature range. [ABSTRACT FROM AUTHOR]

In this study, a resistive random-access memory device based on a Ta/TaxMnyOz/Pt metal–insulator–metal structure was fabricated and examined. The test device exhibited stable bipolar resistive switching characteristics with DC endurance of more than 300 cycles and robust retention up to 104 s at room temperature. Moreover, the device had a low forming voltage and a resistance window of ~ 103. The conduction mechanism in each resistance state of the device was analyzed through current–voltage curve fitting. It was confirmed that the primary conduction mechanisms were ohmic and Poole–Frenkel conduction in the low- and high-resistance states, respectively. By analyzing the cross section of the fabricated device through transmission electron microscopy, it was found that the TaxMnyOz layer was deposited in amorphous form. The composition and chemical bonding state of the TaxMnyOz layer were also analyzed using X-ray photoelectron spectroscopy. With these characteristics, the amorphous TaxMnyOz layer has strong potential for nonvolatile memory applications. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate the potential capability to control Tamm plasmon-polaritons (TPP) by applying atomic layer deposition (ALD) as a highly precise technique for plasmonic applications. Applications in plasmonics usually require tens of nanometers or less thick layers; thus, ALD is a very suitable technique with monolayer-by-monolayer growth of angstrom resolution. Spectroscopic ellipsometry and polarized reflection intensity identified the TPP resonances in the photonic band gap (PBG) formed by periodically alternating silicon oxide and tantalum oxide layers. The sub-nanometer control of the Al2O3 layer by ALD allows precise tailoring of TPP resonances within a few nanometers of spectral shift. The employing of the ALD method for the fabrication of thin layers with sub-nanometer thickness accuracy in more complex structures proves to be a versatile platform for practical applications where tunable plasmonic resonances of high quality are required. [ABSTRACT FROM AUTHOR]

Inspired by biological neuromorphic computing, artificial neural networks based on crossbar arrays of bilayer tantalum oxide memristors have shown to be promising alternatives to conventional complementary metal‐oxide‐semiconductor (CMOS) architectures. In order to understand the driving mechanism in these oxide systems, tantalum oxide films are resistively switched by conductive atomic force microscopy (C‐AFM), and subsequently imaged by kelvin probe force microscopy (KPFM) and spatially resolved time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). These workflows enable induction and analysis of the resistive switching mechanism as well as control over the resistively switched region of the film. In this work it is shown that the resistive switching mechanism is driven by both current and electric field effects. Reversible oxygen motion is enabled by applying low (<1 V) electric fields, while high electric fields generate irreversible breakdown of the material (>1 V). Fully understanding oxygen motion and electrical effects in bilayer oxide memristor systems is a fundamental step toward the adoption of memristors as a neuromorphic computing technology. [ABSTRACT FROM AUTHOR]

Resistive Random-Access Memory (RRAM) presents a transformative technology for diverse computing and artificial intelligence applications. However, variability in the high resistance state (HRS) has proved to be a challenge, impeding its widespread adoption. This study focuses on optimizing TaOx-based RRAMs by strategically placing a nitrogen-doped TaOx barrier-layer (BL) to mitigate variability in the HRS. Through comprehensive electrical characterization and measurements, we uncover the critical influence of BL positioning on HRS variability and identify the optimal location of the BL to achieve a 2x lowering of HRS variability as well as an expanded range of operating voltages. Incremental reset pulse amplitude measurements show that the TaOx:N maintains a low HRS variability even at higher operating voltages when the position of the BL is optimized. Our findings offer insights into stable and reliable RRAM operation, highlighting the potential of the proposed BL to enhance the functionality of TaOx-based RRAMs and elevate overall device performance.

The scientific interest on hybrid materials is mainly related to understanding the types of interactions between inorganic and organic component and the effect of these interactions on the properties of the new material formed. Hybrid nanostructured materials and especially dielectrics are used for electronics (for gate layer) and especially those applicable in structure of different types of thin film transistors (TFTs). In this paper is presented the research on thin film hybrid materials based on tantalum oxide (Ta2O5) starting with inorganic precursor - tantalum ethoxide and polymethylmethacrylate (PMMA). The chemical method sol -gel involves the precursor-tantalum ethoxide which is hydrolysed and functionalized (with special siloxane compound), and the organic methyl methacrylate monomer. The chemical reactions take place at low temperature below 160 oC. The sol is deposited as thin films by spin-coating to analyse intensity-voltage (I-V) and capacitance-voltage curves (C-V) to determine the electric properties. Metal-Insulator-Metal (MIM) structures were made-up for electric characterisation. The value of leakage currents was between 10-10 - 10-7 A at ± 40 V. The hybrid films were analysed by scanning electron microscopy (SEM) for thickness and morphology and for thermal stability the sol was investigated by TG and DSC. The dielectric permittivity ranges between 3.5 and 4 at 1 MHz, depending on the tantalum alkoxide: MMA molar ratio, showing good behaviour for gate layer in future TFTs.

AbstractAlong with its wide range of potential applications, human exposure to mesoporous tantalum oxide nanomaterials (PEG@mTa2O5) has substantially risen. Accumulative toxic investigations have shown the PEG@mTa2O5 intake and cardiovascular diseases (CVD). Endothelial cell death is crucial in the onset and development of atherosclerosis. Still, the molecular mechanism connecting PEG@mTa2O5 and endothelium apoptosis remains unclear. Herein, we studied the absorption and toxic action of mesoporous tantalum oxide (mTa2O5) nanomaterials with polyethylene glycol (PEG) utilizing human cardio microvascular endothelial cells (HCMECs). We also showed that PEG@mTa2O5 promoted apoptosis in endothelial cells using flow cytometry and AO-EB staining. In conjunction with the ultrastructure modifications, PEG@mTa2O5 prompted mitochondrial ROS production, cytosolic Ca2+ overload, ΔΨm collapse, and ER stress verified by elevated ER-Tracker staining, upregulated XBP1 and GRP78/BiP splicing. Remarkably, the systemic toxicity and blood compatibility profile of PEG@mTa2O5 can greatly improve successive therapeutic outcomes of NMs while reducing their adverse side effects. Overall, our findings suggested that PEG@mTa2O5-induced endothelium apoptosis was partially mediated by the activation of the endoplasmic reticulum stress-mitochondrial cascade.

Ti/IrO2-Ta2O5 electrodes are extensively utilized in the electrochemical industries such as copper foil production, cathodic protection, and wastewater treatment. However, their performance degrades rapidly under high current densities and severe oxygen evolution conditions. To address this issue, we have developed a composite anode of Ti/Ta-Ti/IrO2-Ta2O5 with a Ta-Ti alloy interlayer deposited on a Ti substrate by double-glow plasma surface alloying, and the IrO2-Ta2O5 surface coating prepared by the traditional thermal decomposition method. This investigation indicates that the electrode with Ta-Ti alloy interlayer reduces the agglomerates of precipitated IrO2 nanoparticles and refines the grain size of IrO2, thereby increasing the number of active sites and enhancing the electrocatalytic activity. Accelerated lifetime tests demonstrate that the Ti/Ta-Ti/IrO2-Ta2O5 electrode exhibits a much higher stability than the Ti/IrO2-Ta2O5 electrode. The significant improvement in electrochemical stability is attributed to the Ta-Ti interlayer, which offers high corrosion resistance and effective protection for the titanium substrate.

Looseness and infection are the two main reasons for failure of titanium (Ti) based implants (TBI), and offering TBI with superb osteogenesis and bactericidal effects is especially promising for orthopedic applications. Herein, a micro-arc oxidation (MAO) coating including germanium oxide (GeO2), tantalum oxide (Ta2O5) and titanium dioxide (TiO2) on Ti (MTG) surface was created through simultaneous dispersing Ge and Ta particles in the basic electrolyte. In comparison with Ti, the simultaneous deposition of Ge and Ta particles onto the MAO coating led to the change of surface characters (e.g., topography, hydrophilicity, roughness, and protein absorption) of MTG. Moreover, MTG exhibited exceptional corrosion resistance because of presence of Ta2O5. In addition, MTG significantly facilitated the cell response (e.g., attachment, multiplication, and osteoblastic differentiation) due to the existence of Ta2O5. Further, MTG revealed excellent bactericidal capability, which was ascribed to the sustained-release of Ge ions from the MAO coating. Accordingly, simultaneous deposition of Ge and Ta particles onto the MAO coating resulted in a novel implantable biomaterial of MTG with illustrious osteogenic and antibacterial capability as well as corrosion resistance. In short, MTG with excellent cytocompatibility possessed great potential for dental and load-bearing bone replacements. [ABSTRACT FROM AUTHOR]

The results of the formation and certification of the surface morphology and chemical composition and also the results of the study of radiation upon heating to high temperatures (600–800°C) of Ta2O5 nanocluster films obtained by sputtering a Ta target in an atmosphere of Ar and O2 gases with subsequent filtering of the formed clusters according to the selected sizes and their deposition on a metal substrate (Ta) are presented. Surface images were obtained by atomic force microscopy (in situ), and it was shown that Ta films have a loose structure consisting of close-packed spherical nanoparticles. XPS analysis of the chemical composition showed that the resulting films are of high purity and are close to the compound Ta2O5. Using a spectrometer with a working range of 600–1700 nm, the emission spectra of films and substrates with natural tantalum oxide were obtained when heated to various temperatures. It is shown that films with small cluster sizes (2–3 nm) have a more stable emissivity at varying temperatures than films with large clusters (4–5 nm). In addition, when heated to the same temperature, small tantalum oxide clusters radiate more efficiently than a substrate with natural tantalum oxide film. The question is raised about the prospects of using the obtained structures as part of selective emitters to improve the efficiency of thermophotovoltaic systems. [ABSTRACT FROM AUTHOR]

The results of the scanning tunneling spectroscopy study of the electronic states of tantalum nanoclusters on a silicon substrate are presented. Nanoclusters are fabricated by cluster deposition from the gas phase using magnetron sputtering of a tantalum target. Clusters are formed using a Nanogen-50 cluster source (Mantis Deposition) with a quadrupole mass filter integrated into the preparation chamber of an Omicron Multiprobe MXPS VT AFM-25 ultrahigh vacuum system. It is established that the tunneling current differs significantly for spherical nanoclusters of different sizes, and the measured differential current–voltage characteristic of nanoclusters near the Fermi energy is nonmonotonic, which may indicate a change in the density of states near the Fermi energy. This change in the tunneling conductivity of nanoclusters depending on their size indicates the metal–nonmetal transition in metal nanoclusters on the semiconductor surface as the cluster size decreases. [ABSTRACT FROM AUTHOR]

We demonstrate the development of a label-free, impedance-based biosensor by using a passivation layer of 50-nm tantalum pentoxide (Ta2O5) on interdigitated electrodes (IDE). This layer was fabricated by atomic layer deposition (ALD) and has a high dielectric constant (high- κ), which improves the capacitive property of the IDE. We validate the biosensor's performance by measuring uromodulin, a urine biomarker for kidney tubular damage, from artificial urine samples. The passivation layer is functionalized with uromodulin antibodies for selective binding. The passivated IDE enables the non-faradaic impedance measurement of uromodulin concentrations with a measurement range from 0.5 ng/mL to 8 ng/mL and with a relative change in impedance of 15 % per ng/mL at a frequency of 150 Hz (log scale). This work presents a concept for point-of-care biosensing applications for disease biomarkers. [ABSTRACT FROM AUTHOR]

Along with its wide range of potential applications, human exposure to mesoporous tantalum oxide nanomaterials (PEG@mTa2O5) has substantially risen. Accumulative toxic investigations have shown the PEG@mTa2O5 intake and cardiovascular diseases (CVD). Endothelial cell death is crucial in the onset and development of atherosclerosis. Still, the molecular mechanism connecting PEG@mTa2O5 and endothelium apoptosis remains unclear. Herein, we studied the absorption and toxic action of mesoporous tantalum oxide (mTa2O5) nanomaterials with polyethylene glycol (PEG) utilizing human cardio microvascular endothelial cells (HCMECs). We also showed that PEG@mTa2O5 promoted apoptosis in endothelial cells using flow cytometry and AO-EB staining. In conjunction with the ultrastructure modifications, PEG@mTa2O5 prompted mitochondrial ROS production, cytosolic Ca2+ overload, ΔΨm collapse, and ER stress verified by elevated ER-Tracker staining, upregulated XBP1 and GRP78/BiP splicing. Remarkably, the systemic toxicity and blood compatibility profile of PEG@mTa2O5 can greatly improve successive therapeutic outcomes of NMs while reducing their adverse side effects. Overall, our findings suggested that PEG@mTa2O5-induced endothelium apoptosis was partially mediated by the activation of the endoplasmic reticulum stress-mitochondrial cascade. [ABSTRACT FROM AUTHOR]