Diffusion Of Oxygen Vacancies Research Articles

Regulation oxygen vacancy in Ba0.9La0.1Co0.7Fe0.2Nb0.1O3-δ cathode with improved hydration activity for proton ceramic fuel cells

Proton ceramic fuel cells (PCFCs) are gaining attention due to their high energy conversion efficiency. However, the development of PCFCs is hindered by the lack of efficient and robust cathode materials. This article proposes a solution by introducing certain cationic deficiency into the Ba0.9La0.1Co0.7Fe0.2Nb0.1O3-δ (BLCFN) cathode matrix, which results in abundance of oxygen vacancies as well as enhanced proton defects. Consequently, the catalytic activity and hydration activity of the BLCFN oxygen electrode are improved during the reduction reaction process. Specifically, the polarization impedance (Rp) of the (Ba0.9La0.1)0.95Co0.7Fe0.2Nb0.1O3-δ (BL95CFN) decreases by 20% compared to the pristine BLCFN, reaching 0.12 Ω·cm2 at 700 °C in air. The Rp of BL95CFN decreases by 12% in a steam environment of 20 vol%. This enhancement is attributed to the higher concentration of oxygen vacancies, which leads to an improved proton diffusion rate and hydration performance. The peak power density of the anode-supported BL95CFN | BZCYYb | BZCYYb-NiO single cell reaches 641 mW cm−2 at 700 °C, and the performance of this single cell remains stable for nearly 100 h. These findings highlight the vital role of adjusting oxygen vacancy and proton diffusion, providing a feasible strategy for improving the performance and stability of PCFC cathode materials.

Oxygen vacancy migration and impact on high voltage DC polarization in 0.8BaTiO3–0.2BiZn0.5Ti0.5O3

AbstractElectrical polarization and defect transport are examined in 0.8BaTiO3–0.2BiZn0.5Ti0.5O3, an attractive capacitor material for high power electronics. Oxygen vacancies are suggested to be the majority charge carrier at or below 250°C with a grain conduction hopping activation energy of 0.97 eV and 0.92 eV for thermally stimulated depolarization current (TSDC) and impedance spectroscopy measurements, respectively. At higher temperature, thermally generated electronic conduction with an activation energy of 1.6 eV is dominant. Significant oxygen vacancy concentration is indicated (up to ∼1%) due to cation vacancy formation (i.e., acceptor defects) from observed Bi (and likely Zn) volatility. Oxygen vacancy diffusivity is estimated to be 10−12.8 cm2/s at 250°C. Low diffusivity and high activation energies are indicative of significant defect interactions. Dipolar oxygen vacancy defects are also indicated, with an activation energy of 0.59 eV from TSDC measurements. The large oxygen vacancy content leads to a short lifetime during high voltage (30 kV/cm), high temperature (250°C) direct current (DC) electrical measurements.

Approaching the Ideal Linearity in Epitaxial Crystalline-Type Memristor by Controlling Filament Growth.

Brain-inspired neuromorphic computing has attracted widespread attention owing to its ability to perform parallel and energy-efficient computation. However, the synaptic weight of amorphous/polycrystalline oxide based memristor usually exhibits large nonlinear behavior with high asymmetry, which aggravates the complexity of peripheral circuit system. Controllable growth of conductive filaments is highly demanded for achieving the highly linear conductance modulation. However, the stochastic behavior of the filament growth in commonly used amorphous/polycrystalline oxide memristor makes it very challenging. Here, the epitaxially grown Hf0.5Zr0.5O2-based memristor with the linearity and symmetry approaching ideal case is reported. A layer of Cu nanoparticles is inserted into epitaxially grown Hf0.5Zr0.5O2 film to form the grain boundaries due to the breaking of the epitaxial growth. By combining with the local electric field enhancement, the growth of filament is confined in the grain boundaries due to the fact that the diffusion of oxygen vacancy in crystalline lattice is more difficult than that in the grain boundaries. Furthermore, the decimal operation and high-accuracy neural network are demonstrated by utilizing the highly linear and multi-level conductance modulation capacity. This method opens an avenue to control the filament growth for the application of resistance random access memory (RRAM) and neuromorphic computing.

Effect of Mn (as an acceptor) on the structural and electrical properties of non-stoichiometry Sodium Bismuth Titanate/NBT ceramics

The lead free Na0.5Bi0.5TiO3 (NBT) ceramic is proven as a potential piezoelectric candidate; however, non-stoichiometry NBT serves as an outstanding oxide-ion conductor proposed by (M. Li et al., Nature Materials 13 (2014) 31–35). According to this point here we have systematically report the structural and electrical properties of non-stoichiometry Na0.5Bi0.49TiO3/NB0.49T and B-site Mn3+ acceptor-modified NB0.49T system. Therefore, we are trying to prepare the nominal formula of Na0.5Bi0.49Ti1-xMnxO3; NB0.49T ceramic with 0.0≤x ≤ 0.05 by solid state reaction method. The bulk oxide ion conductivity gradually increases with respect to the doping concentration and the maximum value was obtained for x = 0.05 composition. This conductivity maximum is in good consistent with R. A. De Souza's oxygen vacancy diffusivity limit concept for perovskite systems (Advanced Functional Materials, 25 (2015)). On doping of 5mol% of Mn in the Ti-site/B-site NB0.49T system, it was observed that the oxygen-ion conduction inside the grain boundary increased considerably. Grain conductivity of NaBi0.49TiO3 at 500 °C is ∼3.0 ± 0.5 mS cm−1, which is approximately 122 % greater than that pure NBT compositions. Additionally, NB0.9T -exhibited a conductivity value of 4.7 mS/cm at 500 °C, which increases to 9.2 mS/cm on 5 mol% Mn-modification. The observed increase in conductivity was ascribed due to the electrostatic interactions between Mn–Ti or Mn–O bond. Therefore, our current findings on NB0.49T illustrates that present approach should be applicable to modify the system for SOFC application.

Strong Immunity to Drain-Induced Barrier Lowering in ALD-Grown Preferentially Oriented Indium Gallium Oxide Transistors.

Drain-induced barrier lowering (DIBL) is one of the most critical obstacles degrading the reliability of integrated circuits based on miniaturized transistors. Here, the effect of a crystallographic structure change in InGaO [indium gallium oxide (IGO)] thin-films on the DIBL was investigated. Preferentially oriented IGO (po-IGO) thin-film transistors (TFTs) have outstanding device performances with a field-effect mobility of 81.9 ± 1.3 cm2/(V s), a threshold voltage (VTH) of 0.07 ± 0.03 V, a subthreshold swing of 127 ± 2.0 mV/dec, and a current modulation ratio of (2.9 ± 0.2) × 1011. They also exhibit highly reliable electrical characteristics with a negligible VTH shift of +0.09 (-0.14) V under +2 (-2) MV/cm and 60 °C for 3600 s. More importantly, they reveal strong immunity to the DIBL of 17.5 ± 1.2 mV/V, while random polycrystalline In2O3 (rp-In2O3) and IGO (rp-IGO) TFTs show DIBL values of 197 ± 5.3 and 46.4 ± 1.2 mV/V, respectively. This is quite interesting because the rp- and po-IGO thin-films have the same cation composition ratio (In/Ga = 8:2). Given that the lateral diffusion of oxygen vacancies from the source/drain junction to the channel region via grain boundaries can reduce the effective length (Leff) of the oxide channel, this improved immunity could be attributed to suppressed lateral diffusion by preferential growth. In practice, the po-IGO TFTs have a longer Leff than the rp-In2O3 and -IGO TFTs even with the same patterned length. The effect of the crystallographic-structure-dependent Leff variation on the DIBL was corroborated by technological computer-aided design simulation. This work suggests that the atomic-layer-deposited po-IGO thin-film can be a promising candidate for next-generation electronic devices composed of the miniaturized oxide transistors.

Comprehensive understanding of charge and mass transport in BaZr0.1Ce0.7Y0.1Yb0.1O3−δ

This work reports transport properties of BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb1711), studied during oxidation/reduction and hydration/dehydration using electrical conductivity relaxation (ECR) measurements. The oxidation/reduction displayed typical monotonic conductivity relaxation behavior, attributed to the ambipolar diffusion of oxygen vacancies (Vo∙∙) and electron-holes (h∙), and oxygen surface exchange coefficient (k) were >1 order of magnitude higher than bulk diffusivities (D˜), indicating a diffusion-controlled process. Whereas, hydration/dehydration displayed a temperature-dependent gradual transition from monotonic to non-monotonic relaxation profile. At lower temperatures, transient defect concentration profile indicated that overall hydration/dehydration involved an acid-base-type reaction, comprising the diffusion of oxygen vacancy (Vo∙∙) and proton (Hi∙) couples. However, at higher temperatures and high [h∙], it involved a combination of a hydrogenation reaction (comprising component H via diffusion of h∙ and Hi∙ couple) and an oxidation reaction (involving component O via diffusion of h∙ and Vo∙∙ couple), thus giving rise to a two-fold non-monotonic relaxation profile. The k and D˜ values for oxygen vacancies (kVO∙∙; DVO∙∙) were lower than those for protons (kHi∙;DHi∙) with the respective Ea being 57.51 ± 3.14 and 60.72 ± 1.48 kJ∙mol−1 for oxygen-vacancies and 68.78 ± 12.65 and 71.05 ± 13.87 kJ∙mol−1 for protons.

Filament-based memristor switching model

The filaments rupture and recovery in oxide-type memristors have been theoretically studied. The model is based on the kinetics of oxygen vacancies and includes Joule heating of the oxide medium, which enhances the diffusion and drift of oxygen vacancies in an external electric field. The current-voltage characteristic of the model structure was obtained. Comparison with experimental results allowed for the determination of the constants used in the modeling. The peculiarity of the current-voltage characteristic observed in experimental works is explained.

Investigation of the passive film of nanocrystalline 304 stainless steel in 3.5 wt% NaCl solution under hydrostatic pressure

In this paper, the effect of hydrostatic pressure on the passive film of coarse crystalline 304 stainless steel (304 SS) and sputtered nanocrystalline stainless steel (304 NC) in 3.5 wt% NaCl solution has been investigated using in-situ electrochemical measurement techniques. The results indicate that nanosizing promotes the growth of the passive film. Hydrostatic pressure changes the nucleation mechanism of the passive film, decreases the carrier density and oxygen vacancy diffusivity, and decreases the content of oxides and hydroxides within the film, significantly deteriorating the corrosion resistance of the passive film. The point defect model (PDM) was introduced to elaborate the microscopic process of the surface passivation of stainless steel under hydrostatic pressure.

Achieving simultaneously low loss tangent and high resistivity in MgO modified Sr0.979Y0.014TiO3 colossal-permittivity ceramics via inhibiting the diffusion of oxygen vacancies

Colossal permittivity (CP, Ɛr) ceramics are highly desired for promising applications in modern electronic industry. However, actual applications of CP ceramics were seriously limited by large dielectric loss(tanδ), strong temperature/frequency/electric field dependence, and resistance degradation behavior. Here, we proposed a novel strategy to inhibit the diffusion of oxygen vacancies to obtain a CP Sr0.979Y0.014TiO3 (SYT14) ceramic with a combination of low tanδ and high insulation resistivity (ρ), by MgO addition, due to the formation of [MgTi″−VO••], [MgTi″−2YSr•] and highly insulated phase at the grain boundary. SYT14-7M (x = 0.7 wt% MgO) ceramic has excellent comprehensive properties, such as, Ɛr is 28156, tanδ is 0.0136, and ρ is 7.02 × 1011 Ω•cm. The phenomenon of “resistance oscillation” reflects the active degree of oxygen vacancy diffusion behavior. The highly insulated phase forming at the grain boundary can significantly inhibit oxygen vacancy diffusion and electron migration. The temperature range related to active oxygen vacancy diffusion is between 400 and 500 °C.

Thermal activation energy on electrical degradation process in BaTiO3 based multilayer ceramic capacitors for lifetime reliability

For a high capacitance and high lifetime reliability of multilayer ceramic capacitors for automotive applications, the activation energy on thermal activation process can typically be calculated by using Arrhenius based Prokopowicz–Vaskas equation as a method for lifetime prediction. In this study, it is clearly observed that the activation energy shows to be constant in the range of ~ 1.5 eV for the prototype MLCCs, higher than the activation energy values of ~ 1.0 eV related to the motion or diffusion of oxygen vacancies reported in the previous literature. The activation energy value of ~ 1.5 eV for three prototype MLCCs is close to a half the energy band gap (Eg/2 ≈ 1.6 eV) of BaTiO3 obtained from specific environment, where oxygen vacancies are stabilized by external containment such as the effect of rare earth oxide additives. Due to an obvious difference in activation energy values, it difficult to explain the conduction mechanism for failure by only oxygen vacancy migration. Therefore, the concepts of electronic processes and oxygen vacancy should be considered together to understand conduction mechanism for failure of BaTiO3-based MLCCs in thermal activation processes. It can be useful as an indicator for future MLCC development with high lifetime reliability.

(Invited) Oxide Ion Conductivity and Oxide Vacancy Diffusion Coefficient of Stabilized ZrO2 and Doped CeO2 Discussed Based on Classical Defect Chemistry with Particular Focus on Valence State (2+, 3+, and 4+) of Doped Cations

So far tremendous works have been reported on the oxide-ion conductivity of fluorite-type oxides typically stabilized zirconia and doped ceria. It is well known that the oxide-ion conductivity vs. dopant concentration plot shows maximum around 10 mol percent dopant concentration and the maximum conductivity varies with the dopant species. Interests tend to be focused on the higher and the stabler conductivity. For the aim, explorations are made on the dopant survey and the phase stability of the solid solution.Generally, conductivity is considered proportional to the product of carrier concentration and carrier mobility. For the fluorite-type oxide ion conductors, it is considered that carrier is oxygen vacancy, V O ··, and mobility is proportional to oxygen vacancy diffusion coefficient, DV . However, such defect chemical approach to the fluorite-type oxides is not popular. When we assume that the mobility is constant following the classical hypothesis, we cannot explain the conductivity maximum.The author has been trying to discuss the oxide-ion conduction in fluorite-type oxide solid solutions in terms of oxygen vacancy concentration, cV ,and DV .Using the literature data on conductivity and composition relationship, the author has already calculated DV for some compositions of stabilized zirconia and doped ceria as a function of composition. The data have been published in a short review [1] and books [2,3]. However, the published graphical displays were so crowded that the physical meanings seem still unclear.In this presentation, discussion is made on the conductivity of stabilized zirconia and doped ceria in the following order to make clear the characteristic feature of DV with the variation of valence state and chemical species of dopant oxides.1: zirconia base solid solutions 1a: with divalent cation oxides 1b: with trivalent cation oxides2: ceria base solid solutions 2a: with divalent cation oxides 2b: with trivalent cation oxides3: stabilized zirconia – ceria solid solutions 3a: stabilized zirconia base solid compositions 3b: ceria base solid compositions 3c: trivalent cerium formation by partial reductionIt is clarified that DV of fluorite type oxide is affected by the dopant cation not only by different valent but also by the same valent cations.

High-speed mapping of surface charge dynamics using sparse scanning Kelvin probe force microscopy

Unraveling local dynamic charge processes is vital for progress in diverse fields, from microelectronics to energy storage. This relies on the ability to map charge carrier motion across multiple length- and timescales and understanding how these processes interact with the inherent material heterogeneities. Towards addressing this challenge, we introduce high-speed sparse scanning Kelvin probe force microscopy, which combines sparse scanning and image reconstruction. This approach is shown to enable sub-second imaging (>3 frames per second) of nanoscale charge dynamics, representing several orders of magnitude improvement over traditional Kelvin probe force microscopy imaging rates. Bridging this improved spatiotemporal resolution with macroscale device measurements, we successfully visualize electrochemically mediated diffusion of mobile surface ions on a LaAlO3/SrTiO3 planar device. Such processes are known to impact band-alignment and charge-transfer dynamics at these heterointerfaces. Furthermore, we monitor the diffusion of oxygen vacancies at the single grain level in polycrystalline TiO2. Through temperature-dependent measurements, we identify a charge diffusion activation energy of 0.18 eV, in good agreement with previously reported values and confirmed by DFT calculations. Together, these findings highlight the effectiveness and versatility of our method in understanding ionic charge carrier motion in microelectronics or nanoscale material systems.

Oxygen vacancy diffusion and dynamics in Gd-doped CeO2: A GGA+U study

Using a generalized gradient approximation + Hubbard U method in the framework of density functional theory, we investigate the oxygen vacancy (VO) diffusion and dynamics in 3 × 3 × 3 CeO2 supercells with two Gd substitutions for Ce and an oxygen vacancy. Results show that (i) VO always migrates along the <100> direction, and (ii) VO would rather migrate across the Ce–Ce edges than across Ce–Gd or Gd–Gd edges. Especially, Gd only positively influences the migrations of oxygen vacancies within the third nearest neighbor, indicating that the increased Gd doping is required for extending the positive influence to the long-distance diffusion of oxygen vacancy, which offers an accountable explanation for the enhanced ion conduction experimentally observed in CeO2 with high Gd doping. The negative influence of heavy Gd doping on the VO diffusion is also discussed in detail. The outcome of the current work has implications in illuminating the role of dopants toward expediting the oxygen vacancy diffusion and in promoting the performance in CeO2-based materials and devices for environmentally friendly applications.

Atomistic Insights into Medium-Entropy Perovskites for Efficient and Robust CO2 Electrolysis.

Solid oxide electrolysis cells (SOECs) show great promise in converting CO2 to valuable products. However, their practicality for the CO2 reduction reaction (CO2RR) is restricted by sluggish kinetics and limited durability. Herein, we propose a novel medium-entropy perovskite, Sr2(Fe1.0Ti0.25Cr0.25Mn0.25Mo0.25)O6-δ (SFTCMM), as a potential electrode material for symmetrical SOEC toward CO2RR. Experimental and theoretical results unveil that the configuration entropy of SFTCMM perovskites contributes to the strengthened metal 3d-O 2p hybridization and the reduced O 2p bond center. This variation of electronic structure benefits oxygen vacancy creation and diffusion as well as CO2 adsorption and activation and ultimately accelerates CO2RR and oxygen electrocatalysis kinetics. Notably, the SFTCMM-based symmetrical SOEC delivers an excellent current density of 1.50 A cm-2 at 800 °C and 1.5 V, surpassing the prototype Sr2Fe1.5Mo0.5O6-δ (SFM, 1.04 A cm-2) and most of the state-of-the-art electrodes for symmetrical SOECs. Moreover, the SFTCMM-based symmetrical SOEC demonstrates stable CO2RR operation for 160 h.

Exploration on the Stress‐induced Internal Corrosion of NaCl-deposited GH4169 under humid intermediate temperature environments

The internal corrosion penetration of GH4169 with NaCl-deposited in humid environments was analyzed by graded times, stress levels and temperatures. Dynamic principles are proposed that the depth increases with time by the parabolic law and develops with the stress level exponentially in limited exposure time. Accelerated inward diffusion of oxygen aggravates the penetration due to the reduced growth activation energy, as the stress gradient promoted the diffusion of oxygen vacancies along penetrations. Oversaturated vacancies and voids caused by active corrosion release the stress of oxides’ volume change, affecting the stress gradient, and causing the corrosion penetration to grow negatively.

Investigation of the Reaction Mechanisms in La1-XSrxCo1-YFeyO3 Electrode by DFT Calculations

Solid Oxide Cells (SOCs) are electrochemical devices working at high temperatures for a clean hydrogen and electricity production in electrolysis and fuel cell modes, respectively. This technology has attracted a growing attention thanks to its high efficiency without the use of expensive catalysts. Although SOCs could play a key role in the energy transition, its commercialization at large scale is still limited due to performance and degradation issues. The state of the art oxygen electrode, La1-xSrxCo1-yFeyO3 (LSCF) exhibits a high electrochemical activity combined with a good mixed ionic and electronic conductivity. However, LSCF is prone to decompose under operation with a Strontium segregation at the surface reducing the cell performance over time [1].To date, the driving force of Sr segregation in LSCF and its impact on the cell performance is not precisely understood. However, to be able to discern these phenomena, it is still needed to better understand at atomic scale the mechanisms occurring at the electrode in the absence of Sr segregation. Therefore, we carried out a first study on the bulk properties of the parent material LSF [3] and LSCF using Density Functional Theory (DFT) calculations. Now we turn our attention to the surface properties of LSCF. In particular, the oxygen reduction reaction is decomposed in fuel cell mode into a sequence of elementary reactions. Thereby, a special focus lies on the identification of the rate determining steps limiting the overall reaction.To shade light into this, we modeled the A-site terminated (100) surface of LSCF using a symmetric slab. Our calculations revealed the existence of peroxide species at the surface arising from the reductive adsorption of a dioxygen molecule into a surface oxygen vacancy. Incorporation and dissociation of the peroxide requires a surface oxygen vacancy or sub-surface oxygen vacancy. To make this reaction happen, the peroxide and the vacancy have to encounter each other. Thereby it is still unclear weather the oxygen vacancy diffuses towards the peroxide, or vice-versa. Due to the particular orientation of the peroxide, which does not stand perpendicularly out of the (100) plane, but leans towards the direction between two A-site surface ions (cf. Fig. 1), four possible orientations of the peroxide exist. Thus, on-site rotations of the peroxide and its hopping to nearest neighbor sites are considered, as well as the diffusion of oxygen vacancies on surface and sub-surface. The Nudged Elastic Band (NEB) method is used to calculate the activation barriers. Diffusion coefficients are then determined using Transition State Theory (TST) combined with Kinetic Monte Carlo (KMC) calculations. These diffusion coefficients will be used as inputs to improve the existing elementary kinetic models [3] in order to investigate more precisely the performance and durability of SOCs under working conditions.[1] Chen, K., Jiang, S.P. Surface Segregation in Solid Oxide Cell Oxygen Electrodes: Phenomena, Mitigation Strategies and Electrochemical Properties. Electrochem. Energ. Rev. 3, 730–765 (2020). https://doi.org/10.1007/s41918-020-00078-z[2] Hartmann, C., Geneste, G., Laurencin, J., Hole polarons in LaFeO3 and La1 − x Sr x FeO3 − δ : Stability, trapping, mobility, effect of Sr concentration, and oxygen vacancies. Accepted in Phys. Rev. B. [3] E. Effori, J. Laurencin, E. D. R. Silva, M. Hubert, T. David, M. Petitjean, G. Geneste, L. Dessemond, and E. Siebert, J.Electrochem. Soc. 168, 044520 (2021). Figure 1

Ultrathin SrTiO3-based oxide memristor with both drift and diffusive dynamics as versatile synaptic emulators for neuromorphic computing

Abstract Artificial synapses are electronic devices that simulate important functions of biological synapses, and therefore are the basic components of artificial neural morphological networks for brain-like computing. One of the most important objectives for developing artificial synapses is to simulate the characteristics of biological synapses as much as possible, especially their self-adaptive ability to external stimuli. Here, we have successfully developed an artificial synapse with multiple synaptic functions and highly adaptive characteristics based on a simple SrTiO3/Nb: SrTiO3 heterojunction type memristor. Diverse functions of synaptic learning, such as short-term/long-term plasticity (STP/LTP), transition from STP to LTP, learning–forgetting–relearning behaviors, associative learning and dynamic filtering, are all bio-realistically implemented in a single device. The remarkable synaptic performance is attributed to the fascinating inherent dynamics of oxygen vacancy drift and diffusion, which give rise to the coexistence of volatile- and nonvolatile-type resistive switching. This work reports a multi-functional synaptic emulator with advanced computing capability based on a simple heterostructure, showing great application potential for a compact and low-power neuromorphic computing system.

Suppressing resistance degradation in SrTiO3-based colossal permittivity capacitor material

At present, research on colossal permittivity materials is extensive but challenging to achieve simultaneous properties of colossal permittivity, low loss, and high resistivity. Resistance degradation also restricts industrial application of colossal permittivity materials. In this work, a new method has been proposed to improve resistivity of colossal permittivity ceramics by making metal ions diffuse on ceramic grain boundaries, thus inhibiting the diffusion of oxygen vacancies at grain boundaries. Sr0.99La0.01TiO3(SLT10) ceramics were synthesized by traditional solid-state method, and then Bi2O3 (35%)-Al2O3 (10%)-MgO (20%)-CuO (25%)-SiO2 (10%) mixed oxidant was selected to percolate into ceramics. The resistivity of SLT10 ceramics improved remarkably (from 2.1×108 Ω cm to 1.23×1011 Ω cm under DC 100 V) with a colossal permittivity (16695 @1 kHz) and a low dielectric loss (0.016 @1 kHz), as well as excellent frequency stability (20 Hz–2 MHz) and temperature stability (-170 °C to 375 °C). The source of high insulation resistivity of the SLT10 ceramic sample was discussed. Subsequent examination uncovered that grain in the SLT10 ceramics percolated with metal ions displayed semiconducting characteristics, wherein insulation grain boundaries significantly influenced the ceramic's resistivity and served as formidable potential barriers constraining long-range movement of charge carriers. Experimental analysis demonstrated that the resistance degradation behavior of the SLT10 ceramics was suppressed, the breakdown voltage was increased, and the service life was extended.

Effect of Single Spinel Phase Crystallization on Drain-Induced-Barrier-Lowering in Submicron Length IZTO Thin-Film Transistors

This study shows the effect of single spinel phase crystallization on drain-induced barrier lowering (DIBL) of indium-zinc-tin-oxide (IZTO) thin-film transistors (TFTs) with submicron channel length. The 0.9-μm-long amorphous IZTO (a-IZTO) TFT shows a poor DIBL of 318 mV/V. In contrast, a significant improvement in the DIBL is achieved in the single spinel phase IZTO (s-IZTO) TFT, which could be attributed to the suppression of lateral diffusion of oxygen vacancy (VO) and low VO defects through crystallization-induced enforcement of metal-oxygen bonds. Consequently, 0.9-μm-long s-IZTO TFT reveals a small DIBL of 92 mV/V as well as a high field-effect mobility of 90.1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Vs and a low subthreshold swing of 0.1 V/dec. In addition, reliability against external bias temperature stress is considerably improved through single-phase crystallization, leading to an insignificant threshold voltage shift of +0.4 (–0.4) V under positive (negative) bias stress with electric field of 2 (–2) MV/cm at 60 °C for 10,000 s, respectively, in the 0.9-μm-long s-IZTO TFT.

Ultrahigh insulation resistivity potential under colossal permittivity SrTiO3 based ceramics via controlling oxygen backfill

Effects of annealing atmosphere on the dielectric properties of Sr1-xErxTiO3 ceramics (x = 0–0.014) were systematically investigated in this paper. In x = 0.012 ceramic samples annealed in air, the stable insulation resistivity of over 109 Ω • cm (DC 0–150 V), the CP (16,635 @ 1 kHz, 16,822 @ 1 MHz), and the ultralow dielectric loss (0.006 @ 1 kHz, 0.02 @ 1 MHz) are achieved. Through a thorough examination of dielectric responses, X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectrum, and complex impedance data, it is demonstrated that the defect dipoles [TiTi′−VO··−TiTi′], [ErSr·−TiTi′],[2ErTi′−VO··], [TiTi′−VO·], [ErTi′−VO·] and [ErSr·−ErTi′] form in Sr1-xErxTiO3 (when x = 0.012) ceramic annealed under flowing air. We innovatively used variable temperature in situ resistance monitoring equipment to simulate the industrial environment, the insulating properties and the microscopic mechanism of oxygen vacancy diffusion of ceramics were investigated under different voltages and temperatures, which is of great significance to achieve more desirable colossal permittivity, ultra-low dielectric loss and insulation resistivity performance for real applications.