Tantalum Oxide Research Articles

Production of X-ray absorbing ceramics and products based on them for radiotherapy of the periorbital eye region

The paper presents an innovative method for producing high-density ceramics based on bioinert tantalum oxide (Ta2O5) and eye shield products utilizing spark plasma sintering (SPS) technology. Eye shields are in high demand for protecting the cornea and other parts of the eye from ionizing radiation during periorbital eye procedures, such as laser therapy, radiotherapy, and Mohs micrographic surgery (MMS). The dynamics of consolidation of microcrystalline Ta2O5 powder under spark plasma heating conditions in the temperature range of 1000–1400 °C were investigated. The structure, phase, and elemental composition of polycrystalline ceramic samples, including the calculation of crystal structure parameters, were studied using XRD, SEM, and EDS methods. The optimal SPS parameters for achieving maximum relative density (up to 100 %) and Vickers microhardness (up to 510 H V) of the obtained ceramics were determined. The performance properties of the ceramics were examined under conditions of a session of short-focus radiation therapy applied to the periorbital facial area. A dosimetric assessment of the absorbing capacity of the ceramics under X-ray irradiation in modes from 40 to 120 keV was conducted. A prototype of a ceramic eye shield product based on Ta2O5 was developed and manufactured for the first time using SPS technology.

Analysis and simulation of surface plasmon resonance in tantalum pentoxide and gold layers on a prism

Analysis and simulation of surface plasmon resonance in tantalum pentoxide and gold layers on a prism

Investigation of the evolution and corrosion resistance mechanism of anodized film on Ta surface

The tantalum oxide film was fabricated using an anodization process in a 0.5M H2SO4 electrolyte. The evolution and corrosion resistance mechanism of anodized film on the Ta surface has been investigated by experiments and theoretical calculations. The results indicate that the sample with an anodic oxidation voltage of 20V and an anodic oxidation time of 60 min (Ta20-60) exhibits the thickest oxidation film, measuring 360.00 nm and comprising an outer porous layer and an inner dense layer. Ta20-60 demonstrates the highest Ecorr value of 0.009 V and the lowest Icorr value of 0.879 μA cm−2, with a minimal density of point defects at 1.24 × 1019 cm−3, which imparts superior corrosion resistance. The calculation result shows that the growth rate of Ta anodic oxidation film is controlled by the diffusion and migration of vacancy defects. The O atom passes through one bridge site from the tetrahedral gap to another tetrahedral gap (Path 1) on the complete (110) surface has a low diffusion barrier of 0.470 eV and the shortest diffusion path of 2.04 Å, which is the most favorable path for the diffusion of O atoms. This paper offers a fresh perspective on the corrosion resistance of tantalum while furnishing guidance for improving Ta oxide film performance.

Tantalum oxide nanotube thin films: fabrication, optical properties, and porosity analysis

Tantalum oxide (Ta2O5) nanotubes exhibit remarkable properties and have garnered significant attention across diverse scientific disciplines and technological domains. This research article elucidates the successful preparation of amorphous, well-ordered Ta2O5 nanotubes through anodization in electrolytes incorporating hydrofluoric acid and concentrated sulfuric acid. The study comprehensively investigates the preparation methodology on the morphology of the nanotubes, elucidating their optical properties. Furthermore, the effective refractive index and porosity of the Ta2O5 nanotubes were quantitatively determined, offering valuable insights for the advanced utilization of Ta2O5 in several applications, encompassing battery electrode materials, memory resistors, and sensors.

Structure and Formation Mechanisms in Tantalum and Niobium Oxides in Superconducting Quantum Circuits.

Improving the qubit's lifetime (T1) is crucial for fault-tolerant quantum computing. Recent advancements have shown that replacing niobium (Nb) with tantalum (Ta) as the base metal significantly increases T1, likely due to a less lossy native surface oxide. However, understanding the formation mechanism and nature of both surface oxides is still limited. Using aberration-corrected transmission electron microscopy and electron energy loss spectroscopy, we found that Ta surface oxide has fewer suboxides than Nb oxide. We observed an abrupt oxidation state transition from Ta2O5 to Ta, as opposed to the gradual shift from Nb2O5, NbO2, and NbO to Nb, consistent with thermodynamic modeling. Additionally, amorphous Ta2O5 exhibits a closer-to-crystalline bonding nature than Nb2O5, potentially hindering H atomic diffusion toward the oxide/metal interface. Finally, we propose a loss mechanism arising from the transition between two states within the distorted octahedron in an amorphous structure, potentially causing two-level system loss. Our findings offer a deeper understanding of the differences between native amorphous Ta and Nb oxides, providing valuable insights for advancing superconducting qubits through surface oxide engineering.

UV photodetector based on vertically aligned Ta2O5 nanorods

This work presents the investigation of the GLAD technique to fabricate Tantalum pentoxide (Ta2O5) Nanorods for the application of ultraviolet (UV) photodetector. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), UV–visible absorption, and electrical characterization were performed on the fabricated samples. Ta2O5 amorphous nature was revealed via XRD pattern and selected area electron diffraction (SAED) analysis. FESEM and TEM images reveal the growth of vertical nanorods. In the UV–visible region, there is strong absorption, with a direct bandgap of about 3.9 eV. The electrical analysis was conducted at room temperature for the voltage between −10 and 10 V, revealing the performance of the device, with a high responsivity of 5.7 A/W, detectivity (D*) of 11.62 × 1013, and a noise equivalent power (NEP) value of 2.975 × 10−12. In addition, it has a stable switching response at -3V with a rise time of 0.15 s and a fall time of 0.17 s.

Molecular Layering of an Additive Layer of Silicon Dioxide on Anodized Tantalum and Niobium Oxides

The results of studying the processes of formation of nanolayers of silicon oxide 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. A study of the electrical strength of metal-dielectric-metal (MDM) structures based on tantalum and niobium oxides showed that the introduction of an additive dielectric layer (SiO2) can significantly increase the electrical strength of these structures.

Revealing Detailed Cartilage Function Through Nanoparticle Diffusion Imaging: A Computed Tomography & Finite Element Study

The ability of articular cartilage to withstand significant mechanical stresses during activities, such as walking or running, relies on its distinctive structure. Integrating detailed tissue properties into subject-specific biomechanical models is challenging due to the complexity of analyzing these characteristics. This limitation compromises the accuracy of models in replicating cartilage function and impacts predictive capabilities. To address this, methods revealing cartilage function at the constituent-specific level are essential. In this study, we demonstrated that computational modeling derived individual constituent-specific biomechanical properties could be predicted by a novel nanoparticle contrast-enhanced computer tomography (CECT) method. We imaged articular cartilage samples collected from the equine stifle joint (n = 60) using contrast-enhanced micro-computed tomography (µCECT) to determine contrast agents’ intake within the samples, and compared those to cartilage functional properties, derived from a fibril-reinforced poroelastic finite element model. Two distinct imaging techniques were investigated: conventional energy-integrating µCECT employing a cationic tantalum oxide nanoparticle (Ta2O5-cNP) contrast agent and novel photon-counting µCECT utilizing a dual-contrast agent, comprising Ta2O5-cNP and neutral iodixanol. The results demonstrate the capacity to evaluate fibrillar and non-fibrillar functionality of cartilage, along with permeability-affected fluid flow in cartilage. This finding indicates the feasibility of incorporating these specific functional properties into biomechanical computational models, holding potential for personalized approaches to cartilage diagnostics and treatment.

The comprehensive study of hybrid dielectric layer adopted organic thin film transistors for low voltage operation

Organic electronics hold immense promise due to their flexibility, low-cost processing, and diverse applications. Despite tremendous progress, low-voltage operation has remained a significant hurdle, impacting device efficiency. Our investigation introduces a new class of low voltage driven pentacene transistors, featuring hybrid gate insulators composed of polymer buffer layer and oxygen-plasma reacted high-k metal oxides viz. AlOx, TiOx, and TaOx. We demonstrate that a combination of titanium dioxide (TiOx) as the high-k dielectric layer and poly vinyl phenol (PVP) as a buffer layer in organic thin-film transistors (OTFTs) achieves exceptional performance compared to aluminium oxide (AlOx) and tantalum oxide (TaOx). This innovative approach yields the notable field-effect mobility (1.5 cm2/Vs) and a commendable on/off ratio (3.4 × 104), surpassing devices fabricated with other high-k oxides. The success lies in the PVP’s ability to smooth surfaces and reduce interface defects, while TiOx’s superior dielectric constant fosters stronger gate control. These findings pave the way for the development of next-generation organic devices with significantly lower operating voltages, opening doors for energy-efficient and flexible electronics.

Synthesis of tantalum oxide thin films using RF magnetron sputtering for RRAM application

Resistive Random Access Memory (RRAM) is a prominent contender in the realm of emerging non-volatile memory technologies owing to its numerous advantages like simple structure, low power usage, high speed, and exceptional scalability. In the current study, RRAM device was fabricated using tantalum oxide (TaOx) as a resistive switching insulating oxide layer, which was sandwiched between two conducting electrodes, namely Ag and ITO. RF magnetron sputtering was used to deposit the insulating layer of TaOx at room temperature on the ITO substrate. Further, X-ray reflectivity and hard X-ray photoelectron spectroscopy analyses were conducted to find the thickness, roughness, and elemental composition of the deposited TaOx films. Using a semiconductor analyzer, the RRAM cell's first DC switching characteristics were determined. The data acquired exhibited a resistance ratio (R HRS/R LRS) of 120 showing a good distinction between the two-resistance states. Additionally, a thorough investigation was conducted to examine the electrical conduction mechanism occurring inside the fabricated RRAM device.

Corrosion and tribological properties of ta-C/ta-C: Ta coatings: Analysis of the influence of Ta-O/Ta-C ratio

Multilayer ta-C/ta-C: Ta coatings with varying total thicknesses (300, 600, and 1000 nm) and layer thickness ratios (1:0.5, 1:1, and 1:2) between the ta-C layer and ta-C: Ta layer were prepared. The study investigated the static corrosion resistance and tribological properties of the coatings in the NaCl solution. The static corrosion resistance positive correlation depended on the coating surface's Ta-O/Ta-C ratio. The lowest friction coefficient of 0.05 was obtained from the coating with a total thickness of 1000 nm due to the formation of the graphitized transfer film on the counterpart surface. A decreased sp2/sp3 ratio and the formation of tantalum oxide on the wear scar contributed to the lowest corrosion current, corrosive defect density, and wear rate.

SURFACE PLASMON RESONANCE ANALYSIS FOR BENZENE SENSING MEDIA USING SILVER AND Ta2O5 THIN FILMS

The increasing demand for optical sensors is driven by their wide applications, making surface plasmon resonance (SPR) play a crucial role in this field. In this study, a multilayered thin film consisting of tantalum pentoxide (Ta2O5) and silver (Ag) deposited on a glass prism was used to study SPR. The Ag layer thickness was fixed at 50 nm, while the Ta2O5 layer thickness varied from 0 to 70 nm. The Kretschmann configuration was employed to assess the sensitivity of air and gases with different refractive indices. Therefore, different layer thicknesses along with different wavelengths and angles were investigated. MATLAB software was employed to simulate and analyze SPR with a half-sphere prism to extend the incident angle. The simulation conditions with Fresnel equations were used to calculate the reflectivity and transmittance coefficients for the studied sample. The results revealed that the best output was at a Ta2O5 thickness of 50 nm to get optimal full width at half maximum of 2.4 and sensitivity factor of 162.5. This device works in the visible and infrared regions.

Dual External Field Strategy in Regulating the Superhalogen Characteristics of the Non-Noble Metal Constituted Tantalum Oxide Clusters.

The identification of the non-noble metal constituted TaO cluster as a potential analogue to the noble metal Au is significant for the development of tailored materials. It leverages the superatom concept to engineer properties with precision. However, the impact of incrementally integrating TaO units on the electronic configurations and properties within larger TaO-based clusters remains to be elucidated. By employing the density functional theory calculations, the global minima and low-lying isomers of the TanOn (n = 2-5) clusters were determined, and their structural evolution was disclosed. In the cluster series, Ta5O5 was found to possess the highest electron affinity (EA) with a value of 2.14 eV, based on which a dual external field (DEF) strategy was applied to regulate the electronic property of the cluster. Initially, the electron-withdrawing CO ligand was affixed to Ta5O5, followed by the application of an oriented external electric field (OEEF). The CO ligation was found to be able to enhance the Ta5O5 cluster's electron capture capability by adjusting its electron energy levels, with the EA of Ta5O5(CO)4 peaking at 2.58 eV. Subsequently, the introduction of OEEF further elevated the EA of the CO-ligated cluster. Notably, OEEF, when applied along the +x axis, was observed to sharply increase the EA to 3.26 eV, meeting the criteria for superhalogens. The enhancement of EA in response to OEEF intensity can be quantified as a functional relationship. This finding highlights the advantage of OEEF over conventional methods, demonstrating its capacity for precise and continuous modulation of cluster EAs. Consequently, this research has adeptly transformed tantalum oxide clusters into superhalogen structures, underscoring the effectiveness of the DEF strategy in augmenting cluster EAs and its promise as a viable tool for the creation of superhalogens.

Optimal design of multilayer optical thin film structure for smart energy saving applications using needle optimization approach

In this work, a novel design of a one dimensional photonic crystal (1D PC) is investigated. The 1DPC structure is composed of alternating layers of tantalum pentoxide (Ta2O5) and silicon dioxide (Sio2). The proposed 1D PC structure is designed to act as short wave pass (SWP) edge filter that selectively passes light of short wavelengths, while the infrared light is blocked. In this study, Essential Macleod software is used to create the optimal design with the computational support of the needle synthesis technique. By varying the incidence angle of the mean polarized light mode, we can determine the features of the optimal SWP edge filter design, which leads to an important application for this filter. It can shed light on the filter’s suitability as a smart energy saving window coating for hot climate regions. The study includes different hot regions in Saudi Arabia such as Mecca, Riyadh, Dammam, Arar and Alaqiq. They were used as case studies in this research. According to the study of the optimal design of SWP edge filter applied in Mecca, Riyadh, Dammam, Arar and Alaqiq provinces, the light transmittance in the visible region is more than 99% during the summer solstice and more than 96% during the winter solstice. The photonic band gab (PBG) is almost constant during the summer solstice without shifting or decreasing in size whereas in the winter solstice, the PBG shifts toward the short wavelengths and decreases in size by increasing the angle of incidence. This allows an amount of solar energy to enter in winter. Riyadh, Dammam, and Arar provinces experienced a significant increase in solar energy during the winter solstice, more than Mecca and Alaqiq provinces.

Review of Anodic Tantalum Oxide Nanostructures: From Morphological Design to Emerging Applications.

Anodization of transition metals, particularly the valve metals (V, W, Ti, Ta, Hf, Nb, and Zr) and their alloys, has emerged as a powerful tool for controlling the morphology, purity, and thickness of oxide nanostructures. The present review is focused on the advances in the synthesis of micro/nanostructures of anodic tantalum oxides (ATO) in inorganic, organic, and mixed inorganic-organic type electrolytes with critically highlighting anodization parameters, such as applied voltage, current, time, and electrolyte temperature. Particularly, the growth of ATO nanostructures in fluoride containing electrolytes and their applications are briefly covered. The details of the current- or voltage-time transient and its relation to the growth of the anodic oxide films are presented systematically. The main discussion revolves around the incorporation of various electrolyte species into the surface of ATO structures and its effects on their physicochemical properties. The latest progress in understanding the growth mechanism of nanoporous/nanotubular ATO structures is outlined. Additionally, the impact of annealing temperature (ranging from 400-1000 °C) and atmosphere on the crystalline structure, morphology, impurity content, and physical properties of the ATOs is briefly described. The common modification methods, such as decorating with other transition metal/metal oxide, heteroatom doping, or generating defects in the ATO structures, are discussed. Besides, the review also covers the most promising applications of these materials in the fields of capacitors, supercapacitors, memristive devices, corrosion protection, photocatalysis, photoelectrochemical (PEC) water splitting, and biomaterials. Finally, future research directions for designing ATO-based nanomaterials and their utilities are indicated.

A tantalum oxide based memristive neuron device for anomaly detection application

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.

Pt-decorated tantalum oxide on mesoporous carbon supports for enhanced mass activity and start-stop and load cycling durability in PEFCs

Unique Pt/TaOx/MC cathode electrocatalysts for polymer electrolyte fuel cells (PEFCs) are developed using partially-reduced TaOx decorated on mesoporous carbon (MC). An initial mass activity (MA) of more than 500 A g−1 was observed for a TaOx/MC support heat treated at 700 °C in H2 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 TaOx 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/TaOx/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.

INFLUENCE OF THE NANOSTRUCTURE OF TANTALUM OXIDE ON THE FLARE CHARACTER OF ITS ELECTROLUMINESCENCEWITH ANODIC-ELECTROLYSIS FORMATION IN CHEMICALLY PURE WATER

Theoretical and experimental studies were carried out to identify the reasons for the flash nature of the combustion of electroluminescence (EL) of tantalum oxide (Ta2O5), formed in chemically pure (distilled) water during high-voltage anodization of 1700 s. Nonlinear growth of the Ta2O5 film during this time was established, and a polychrome effect was discovered for its thicknesses from 150 ± 28 nm to 820 ± 80 nm. At the same time, EL ignition begins at an oxide thickness of 390 ± 74 nm, which corresponds to an anodization time of 78 ± 15 s, and from 968 ± 185 s until the end of this process, bright EL flashes are observed. Their luminosity can reach 2.8·10–3 lm/m2. It is shown that the cause of the outbreaks is explosive processes in dynamically changing Ta2O5 pores ranging in size from tens of nanometers to several micrometers and containing gas-discharge plasma from various products of electro- and plasma-chemical reactions with a temperature of the order of 12000 K, created due to Joule heating by the flowing current. It has been established that the formation of the plasma itself occurs as a result of electrical breakdown in pores, the field strength in which can reach the order of 3·108 V/m or more.

Enhanced antibacterial and osteogenic properties of titanium by sputtering a nanostructured fluoride-doped tantalum oxide coating

Infections and poor osseointegration are the main challenges for titanium implants in clinical practice. Herein, we proposed fabricating a novel fluoride-doped tantalum oxide (F-TaOx) coating on titanium by one-step reactive sputtering deposition to endow implants with superior antibacterial and osteogenic ability. By altering the fluorine and oxygen loading amount, the coating’s physicochemical properties, corrosion resistance, antibacterial and osteogenic activities are tuned simultaneously. All coatings exhibit nano-morphology, superhydrophilicity and improved surface hardness. Despite containing fluoride, the F-TaOx coating produced with fluorine and oxygen dual-deposition still shows enhanced corrosion resistance due to the protection of existing metal oxidizes. The antibacterial test reveals that the F-TaOx coating exhibits long-lasting and superior antibacterial properties. The microenvironment acidification by F-, the excessive ROS generation and the disruption of ATP by F-, TiF3 and Ta2O5, and the repulsive force by superhydrophilic surface synergistically result in bacterial death. The cell experiments indicate that the F-TaOx coating shows good cytocompatibility, promote cell spread and osteogenic differentiation by enhancing ALP activities and ECM mineralization. This work provides a promising strategy for the surface functionalization of metallic implants to produce dual anti-infection and osteogenesis effects for orthopedic and dental applications.

Biological activity of tantalum oxide coating doped with calcium and strontium by micro-arc oxidation under osteoimmunomodulation

Tantalum is widely used in clinics due to its excellent properties. However, its high density and elastic modulus constrain its application as a large implant. The new porous tantalum material addresses the issue of incompatibility between the implant and the human body. Nevertheless, it still exhibits biological inertia and limited bone-bonding ability; therefore, it is necessary to modify its surface. At present, some surface modification methods have inconsistent results in vitro and in vivo. To solve this problem, this study described the preparation of a ceramic coating with a "trabeculae-like" structure on the surface of pure tantalum using micro-arc oxidation (MAO). Calcium and strontium ions were introduced by adding acetate to the electrolyte. The effects of incorporating bioactive ions Ca2+ and Sr2+ into the electrolyte on the coating's morphology, coating thickness, phase composition, roughness, hydrophilicity, and the activity of MC3T3-E1 osteoblast cells under osteoimmunomodulation were investigated. The results demonstrated that the introduction of bioactive ions did not change the porous morphology of the coating; instead, it led to an increase in coating thickness, enhancement of surface roughness and hydrophilicity, as well as promotion of osteoblast spreading, proliferation, and ALP activity. Moreover, it regulated the phenotypic polarization of RAW264.7 macrophages to augment osteoblast proliferation, spreading, and ALP activity, implying that the coating has superior osteogenic potential under osteoimmunomodulation.