Interlayer Thickness Research Articles

Kinetics of Nickel Diffusion into Austenitic Stainless Steels AISI 304 and 316L and Calculation of Diffusion Coefficients.

Diffusion bonding has many advantages, but it also has its specifics. When creating heterogeneous joints, problems arise with the creation of intermetallic phases. For this reason, an interlayer is needed to prevent the creation of these unfavorable phases. It is important to ensure that the interlayer is of sufficient thickness to prevent the elements from diffusing through the entire interlayer and the intermetallic phases from being formed again. Conversely, too thick an interlayer causes an increase in the heterogeneity of the bond properties. The creation of the initial diffusion bonds in a heterogeneous diffusion joint of AISI 304 and AISI 316L steel with a 0.2 mm thick nickel interlayer was made in a Gleeble 3500. The experiments to determine the diffusion kinetics were carried out in a vacuum furnace, with subsequent evaluation by EDX (Energy Dispersive X-ray Spectroscopy) analysis. Subsequently, the diffusion coefficients of nickel into both steels were determined, and generalized equations were formulated to calculate the diffusion coefficients for temperatures in the range of 950 to 1150 °C and holding times in the range of 3600 to 18,000 s. Equations are also given to determine the width of the diffused zone between each steel and the Ni interlayer.

ANN-based structure peciliaties evaluation of polymer composite reinforced with unidirectional carbon fiber

At the moment, there is a growing interest in composite materials with matrices based on thermoplastic polymers; these materials are superior to traditional carbon fiber plastics due to higher fracture toughness and impact strength, low smoke generation during combustion, and high thermal and chemical resistance. The deformation behavior of such composite materials due to the high plastic deformation of the matrix differs from the behavior of traditional composites, which must be considered when performing calculations. In our study, as a model object, the features of the microstructure of single carbon thread impregnated with polysulfone were studied in order to evaluate the distribution of misorientation angles of elementary fibers, the degree of their damage, the thickness of the polymer matrix interlayers between elementary fibers in threads impregnated with more viscous thermoplastic binders. Statistical analysis of a large array of micrographs was carried out using specially developed algorithms for computer processing of electron microscopic images of a composite material. Algorithms for processing arrays of images using machine vision algorithms are proposed. Based on the analysis of the data array, the distributions of carbon fibers impregnated with polysulfone were plotted over the misorientation angle of the filaments and over the interfilament distance in the longitudinal and cross sections of the fiber. Using the machine learning method, an algorithm for detecting violations of the filament structure was implemented. The data obtained can be used to refine the calculations of the strength and deformation characteristics of composite materials with thermoplastic matrices.

Stability of a lined rock cavern for compressed air energy storage containing a weak interlayer during blasting in the adjacent cavern: model tests and numerical simulation

To evaluate the stability of a lined rock cavern (LRC) for compressed air energy storage (CAES) containing a weak interlayer during blasting in the adjacent cavern, a newly excavated tunnel-type LRC was taken as the research object. By combining similar model tests and numerical simulation, the dynamic responses and deformation characteristics of the LRC for CAES under joint action of factors including the gas storage pressure, weak interlayer, and blast load were studied. The influences of the thickness, dip angle, and location of the weak interlayer on deformation of the LRC were discussed. The results show that as the gas storage pressure increases, the rate of change in strains in regions of the LRC near the weak interlayer is accelerated, and the gas storage pressure more significantly influences the sealing layer and lining than the surrounding rocks. The presence of the weak interlayer causes stress concentration in the LRC and increases the circumferential strain and residual strain of the LRC. Under the blast load, the right-side wall of the LRC shows the poorest stability, and the presence of the weak interlayer results in the energy loss in the propagation process of stress waves and an increment of peak strain in regions of the LRC around the interlayer. When the weak interlayer is separated from the LRC, as the thickness of the weak interlayer increases, the confinement of surrounding rocks at the interlayer on the LRC reduces and the circumferential strain increases. As the dip angle of the interlayer increases, the peak strain in the right upper side of the LRC grows significantly. As the distance from the weak interlayer to the LRC boundary increases, the circumferential strain in regions of the LRC near the interlayer decreases significantly. If the distance is less than 0.2r, the increment of the distance significantly affects the peak strain.

Improvement of electrical properties by insertion of AlGaN interlayer for N-polar AlGaN/AlN structures on sapphire substrates

In this study, we propose nitrogen-polar (N-polar) Al0.1Ga0.9N/Al0.9Ga0.1N/aluminum nitride (AlN) structures. N-polar Al0.1Ga0.9N/Al0.9Ga0.1N/AlN was grown on a sapphire substrate with a misorientation of 2° with respect to the m-axis using metal–organic vapor deposition. The effects of varying the Al0.9Ga0.1N interlayer thickness from 30 nm to 1 μm using pulsed H2 etching on the planarity and current–voltage characteristics of the samples were investigated. The current first improved upon increasing the interlayer thickness from 30 to 300 nm, owing to the reduction in interfacial impurities between (aluminum) gallium nitride (Al)GaN) and Al0.9Ga0.1N, but subsequently decreased upon further increasing the thickness because of the relaxation growth of the interlayer. Furthermore, pulsed H2 etching of the Al0.9Ga0.1N interlayer suppressed step bunching and improved planarity. Subsequently, the proposed method was employed to fabricate N-polar Al0.1Ga0.9N/Al0.9Ga0.1N/AlN heterostructure FETs, which demonstrated five times higher source-drain current (I DS) than that of conventional structures without an interlayer.

Features of structure formation in antifriction composite powder infiltered with copper alloy material based on iron (pseudo-alloy) under high-temperature thermomechanical treatment

The results of studies of the structure formation process in an iron-based antifriction composite powder material infiltrated with a copper alloy (pseudo-alloy) during thermal and high-temperature thermomechanical treatment (HTMT) are presented. It is shown that after infiltration the structure of the pseudo-alloy consists of sections of the steel skeleton with a perlite structure almost homogeneous in carbon and a small amount of cementite, sections of the copper phase located along the boundaries and at the joints of the particles of the steel skeleton, sulfide inclusions mainly in the copper phase. In the process of hardening, carbon is redistributed in the particles of the steel skeleton; a layer 2–5 µm thick with an increased carbon content is formed at the boundary with the copper phase. During HTMT, the structure is refined, a macrotexture is formed, and the thickness of the copper phase interlayers decreases, depending on the degree of deformation. The degree of deformation also affects the structure of the steel skeleton. After HTMT with a degree of deformation of 30 %, the structure consists of structureless martensite, troosto-martensite and residual austenite, and in the areas adjacent to the copper phase the carbon content is slightly lower, with a degree of deformation of 50 % – structureless martensite, 25 % more austenite content, more uniform distribution of carbon. It has been established that, due to the activation of diffusion processes during deformation during HTMT, molybdenum sulfides decompose and form iron and copper sulfides of various compositions; molybdenum alloys the iron base or forms carbide. The investigation results can be used in the development of high-strength antifriction materials for heavily loaded friction units.

High-Quality AlGaN/GaN HEMTs Growth on Silicon Using Al0.07Ga0.93N as Interlayer for High RF Applications

In this study, AlGaN/GaN high electron mobility transistor (HEMT) with different interlayer thicknesses of Al0.07Ga0.93N were grown by metal-organic chemical vapour deposition (MOCVD) is investigated. The AlGaN/GaN HEMTs have the same device’s structure, with the Al0.07Ga0.93N interlayer thickness varied from 0 to 800 nm. All of the samples demonstrate high crystal quality in the GaN channel, with low dislocation density of (1.34–3.81) × 109 cm−2 and low AFM surface roughness of 0.27–0.39 nm. The heterostructure with an interlayer exhibits better mobility (1750 cm2 V∙s−1) compared to the structure without an interlayer (1610 cm2 V∙s−1). Furthermore, the interlayer improves breakdown voltage, and reduces insertion loss. The DC characteristics show that the 300 nm-thick Al0.07Ga0.93N is beneficial in improving leakage current and iso-breakdown voltage up to 450 V at a spacing of 10 μm. The insertion loss reduces to –0.75 dB mm−1 compared to the structure without an interlayer. The device with a 300 nm-thick Al0.07Ga0.93N interlayer exhibits the potential of RF, including a measured transconductance of 440 mS∙mm−1 and cutoff frequencies of = 48/96 GHz at a given bias point.

Types and sedimentary genesis of barriers and interlayers in the composite turbidite sand bodies of a deep-water canyon: A case study of the Central Canyon in the Qiongdongnan Basin

Deep-water oil and gas is currently the hot spot and difficulty of global oil and gas exploration, and the complex flow process inside the turbidite channels of deep-water canyons makes it difficult to characterize reservoir structures, identify barriers and interlayers and clarify the spatial distribution laws of reservoirs, which restricts the development of deep-water oil and gas. Taking the Central Canyon of the Qiongdongnan Basin as an example, this paper identifies and characterizes the barriers and interlayers of composite channel scale by means of seismic sedimentology, based on three-dimensional seismic and core data. Then, based on the turbidite filling process, barriers and interlayers are classified, and their genesis and control factors are analyzed. Finally, a development model of deep-water barriers and interlayers is established based on the quantitative analysis of sediment transportation system parameters. And the following research results are obtained. First, based on sedimentary genesis, barriers and interlayers are classified into four types, namely mudstone interlayers of lateral (aggradational) turbidite channel genesis (type A), mudstone interlayers of fine-grained turbidite channel genesis (type B), barriers of hemipelagic deep-water sediment genesis (type C), and calcareous petrophysical interlayers (type D). Second, based on the filling stage, barriers and interlayers are divided into four combination sequences, i.e., the initial canyon formation stage with strong sediment supply conditions (type A + type C and type B+ type C), the initial canyon formation stage with weak sediment supply conditions (type B + type C), the stable canyon development/late reworking stage with strong sediment supply conditions (types A + type D), and the stable canyon development/late reworking stage with weak sediment supply conditions (type D). Third, the development types and combination sequences of barriers and interlayers are controlled by the change of sediment transportation volume and terrain slope in the canyon. In the initial canyon formation stage, there is sufficient space for the development of turbidite, and the development of thin barriers and interlayers is controlled by sediment dischage volume, while the development of thick barriers and interlayers is controlled by terrain slope change. In the stable canyon development/late reworking stage, turbidite undergoes superimposed development and overbank. The sediment supply is the primary control factor of barrier and interlayer thickness, and the terrain slope change is the secondary factor. In conclusion, the development model of barriers and interlayers can be used to describe and predict the reservoir structure models under the same sedimentary background and provides a technical support for the exploration and development of deep-water oil and gas.

Interlayer Interaction and Coercivity of Three-Layer Films Оbtained bу Chemical Deposition

Abstract—The results of experimental and theoretical studies of the coercivity and the displacement field of the hysteresis loop on the thickness of the nonmagnetic interlayer in magnetic films obtained by electroless plating are presented. With the help of model calculations based on the Landau–Ginzburg equations, the exchange interactions between magnetic layers with the participation of atoms of the nonmagnetic layer are studied. The resulting expression for the displacement field describes well the exponential changes in the displacement field as a function of the interlayer thickness in structures with both magnetically soft layers and layers with significantly different values of the coercivity.

Effect of Adding Cu2O as a Back Surface Field Layer on the Performance of Copper Manganese Tin Sulfide Solar Cells

One of the major limitations causing deadlock in solar cells with higher sulfur content in the photovoltaic absorber material is the unintended formation of an uncontrollable MoS2 layer between the absorber material and Mo back contact, which can affect negatively the efficiency of solar cells. Researchers reported that it is very difficult to control the MoS2 properties such as the conductivity type, thickness, band gap, and carrier concentration in experiments. Considering these challenges, an initial step involved a thorough examination utilizing the one-dimensional solar cell capacitance simulator (SCAPS-1D) to assess the impact of n-MoS2 interlayer thickness and donor concentration on the performance of CMTS solar cells. Our investigation revealed the formation of a “cliff-like CBO” at the CMTS/n-MoS2 interface, facilitating the transport of electrons from the p-CMTS absorber to the Mo back contact, resulting in a significantly higher recombination rate. Subsequently, herein a novel approach is proposed, using Cu2O as a back surface field (BSF) layer due to its low cost, intrinsic p-type properties, and non-toxic nature. Simulation results of a novel heterostructure (Mo/Cu2O/CMTS/CdS/i-ZnO/AZO/Al) of the CMTS-based solar cell are discussed in terms of recombination rate and conduction band alignment at the absorber/BSF interface. A desired “spike-like CBO” is formed between CMTS/Cu2O, which hinders the transport of electrons to the back contact. By optimizing the physical parameters such as thickness and the doping density of the Cu2O layer, an efficiency η of 21.78% is achieved, with an open circuit voltage (Voc) of 1.26 V, short-circuit current density (Jsc) of 24.45 mA/cm², and fill factor (FF) of 70.85%. Our simulation results offer a promising research direction to further develop highly efficient and low-cost CMTS solar cells.

Mechanical characterization of intermittent weak interlayer based on DIC and acoustic emission technique

Current research on intermittent structural surfaces tends to concentrate on intermittent joints, often neglecting the abundance of intermittent weak interlayers present in rock structures. To analyze the effect of intermittent weak interlayer on the mechanical properties of rock mass, specimens with varied interlayer thickness and dip angles were prepared and subjected to uniaxial compression tests using an acoustic emission system and Digital Image Correlation (DIC) technique. The results revealed an inverse relationship between the interlayer thickness (t) and dip angle (θ), and the uniaxial compressive strength. Through a nonlinear fitting method, an empirical strength equation for these interlayers was established. Acoustic emission (AE) counts and cumulative acoustic emission counts increased with loading, and the RA-AF values indicated that the specimens were dominated by shear damage, and the larger the thickness and dip angle of the interlayer, the higher the proportion of shear damage. In terms of failure mode, the greater the thickness of the interlayer, the lower the level of development of cracks other than the main crack, and the greater the dip angle of the interlayer, the fewer the number of wing cracks required for specimen failure and the lower the degree of wing crack development. The increase in interlayer thickness and dip angle resulted in a specimen structure that was more susceptible to damage. The actual crack initiation angles agree with the theoretically calculated angles based on the maximum tensile stress theory. These findings emphasize the critical role of these parameters in influencing the failure mode of rocks.

Si-containing interlayer using tetramethylsilene for diamondlike carbon film adhesion on low-alloy steel: The role of the interlayer deposition time

Diamondlike carbon (DLC) coatings provide interesting properties for industrial applications. However, the low adhesion of DLC coatings on any type of ferrous alloy compromises technological applications. One possible solution to this issue is the application of adhesion interlayers. The aim of this study is to investigate the adhesion of DLC films on low-alloy steel through the use of silicon-containing interlayers at different deposition times using tetramethylsilane. The role of time on the physical-chemical, microstructural, and tribological properties of the material system was evaluated. The interlayer thickness linearly increased and greater contributions of silicon bonds were measured as a function of the interlayer deposition time. Nevertheless, longer deposition times increased the roughness and defect ratio in DLC coatings. Although good enough adhesion for decorative applications was acquired, no drastic variation in the average critical load (∼4.2 N) for delamination was observed at different deposition times for the samples that achieved adhesion.

Cure path dependency of damage resistance in interlayer toughened composite laminates subjected to quasi-static indentation and low-velocity impact

Cure cycle optimization reduces exotherms, defects and cycle times for thermoset composites, but may change the interlayer microstructure of toughened systems. The question remains, however, how the cure-dependent interlayer microstructure affects laminate mechanical properties. This work studies the effects of cure cycle heating rates on interlayer microstructure and damage resistance of interlayer toughened T800SC/3900-2 laminates, subjected to quasi-static indentation (QSI) and low-velocity impact (LVI). Results show that QSI damage resistance is affected by heating rate and interlaminar microstructure due to the cure-dependent delamination migration. Specifically, a lower heating rate causes separated particles, a thicker interlayer, and more fibre migration into the interlayer, which promotes delamination migration from toughened interlayer to brittle intralayer and consequently weakens the toughening effect. Less delamination migration retains the toughening effect for higher heating rates. In contrast, LVI damage resistance is independent of the cure cycle because delaminations remain in the toughened interlayer for all interlaminar microstructures.

Influence of interlayer types and thicknesses on the blast performance of laminated glass panels

Several new laminated glass (LG) polymer interlayer materials are now available in the market such as Ethylene-Vinyl Acetate (EVA), and SentryGlas (SG). In this paper, quasi-static testing was conducted using a full-scale static water chamber to investigate the influence of interlayer type and thickness on the extreme static response of the LG panels. However, due to the high danger and cost of explosion tests, numerical modeling was used to study the effect of these parameters on the dynamic response of the LG systems. The dynamic numerical model was verified using previously published experimental data. Results demonstrate varying pressure resistance capabilities with changes in interlayer type. EVA interlayer panels exhibit the highest deformation in dynamic behavior, while SG interlayer panels demonstrate the least deformation. Consequently, LG panels with SG interlayers exhibit the highest strength among the three types. Furthermore, the resistance of LG panels improves in the pre-cracked stage by increasing interlayer thickness.

Improved Efficiency Droop of 370 nm UV LEDs with ITO/Au/ITO Structure

In this paper, a method of indium-tin oxide/Au/indium-tin oxide (IAI) structure as transparent conductive layers (TCLs) to improve the current spreading and suppress efficiency droop of ultraviolet light-emitting diodes (UV-LEDs) is investigated. The morphology and distribution of Au clusters formed by annealing are investigate by atomic force microscope and scanning electron microscope. Compared with the UV-LED without Au clusters, the forward voltage of UV-LED is reduced by 5.9% at 20 mA, light output power and wall plug efficiency increase by 64.2% and 84.2% at 300 mA for the UV-LED with IAI structure as the thickness of the Au interlayer is 1 nm. In addition, light emission distribution results show that by inserting Au interlayer, current distributes more uniform and the current spreading characteristics of UV-LED are improved. Ultimately, efficiency droop of the LED has been suppressed.

Al-40Sn ALLOY PRODUCED BY SELECTIVE LASER MELTING OF A MIXTURE OF ELEMENTARY POWDERS

Al-40Sn alloy was synthesized by selective laser melting (SLM) of a mixture of elemental powders. In the structure of the alloy, traces of a semi-elliptical melt are observed, the boundaries of the melt regions are decorated with pores and inclusions of tin. The internal structure of melt traces consists of finely crystalline regions with identically oriented columnar Al crystals separated by thin layers of tin. With an increase in laser power, the rate of crystallization of the melt decreases, and the cells of aluminum crystals increase, and with them the thickness of the tin interlayers separating them also increases. The porosity of the alloy decreases slowly with increasing power, and to minimize it, a change in the parameters of the SLM process is required.

Znucalite, the only known zinc uranyl carbonate: Its crystal structure and environmental implications

Abstract Znucalite is a zinc uranyl-carbonate mineral that was until recently only partially characterized with a formula originally given as Zn12Ca(UO2)(CO3)3(OH)22·4H2O, with an unknown crystal structure and ambiguous symmetry determinations. We have reinvestigated this mineral using three-dimensional electron diffraction (3D ED) and powder X-ray diffraction and revealed for the first time its structural details. Znucalite is unambiguously monoclinic, P21/m, with a = 10.722(2) Å, b = 6.259(1) Å, c = 25.355(1) Å, β = 101.13(1)°, and V = 1669.54(9) Å3. The structure refinement of the 3D ED data using the dynamical approach (Robs = 0.1594 for 3579 observed reflections and 244 parameters) provided the following structure model. Znucalite possesses a layered structure, with a [Zn10(OH)14(CO3)2] double sheet (with Zn2+ both in octahedra and tetrahedra), which is connected to a thick interlayer that hosts U 6+, Ca2+, and H2O molecules. The linkage between structural units and the interlayer occurs via the vertices of ZnO4 tetrahedra protruding from the sheet. In the interlayer, differences in ordering between U and Ca take place and likely cause the difficulties encountered during the attempts to solve the structure. The refined structural formula of znucalite, Zn10Ca0.828[UO2]0.828[CO3]4(OH)15.312(H2O)5.484, corresponds well to the composition obtained from the electron-microprobe analyses, (Zn9.84Al0.16)Σ10.00 Ca0.83(UO2)0.80[(CO3)3.96(SO4)0.04]Σ4.00(OH)15.42(H2O)5.48. Raman spectroscopy evidenced the presence of several non-equivalent CO3 groups, as well as OH and H2O. The U-O bond lengths obtained from the stretching frequencies of UO22+ vibrations are in line with the structural model. A discussion on the environmental importance of znucalite is appended, based on geochemical calculations with an estimate of the solubility product for this mineral.

High-Performance Solid Oxide Electrochemical Cells with Ultrathin and Dense Double-Doped Ceria Interlayers

To mitigate the drastic global climate change, which mainly originated from the indiscriminate use of fossil fuels, various alternative eco-friendly energy conversion technologies have been studied. Among them, solid oxide electrochemical cells (SOCs) are one of the most promising devices with superior power and energy densities and low environmental impact. The current main objective of the SOCs research field is lowering the operating temperature to secure thermal cycling stability and minimize system costs. To achieve a feasible performance for commercial usage at reduced temperatures, it is inevitable to use state-of-the-art cobalt-based oxygen electrode materials. However, cobalt-based materials inherently react with conventional zirconia-based electrolytes at high temperatures forming insulating phases at the interface. Thus, the ceria interlayer is essentially required to prevent unwanted chemical reactions. In this study, we newly developed thin and dense doubly doped ceria interlayers (~250 nm) using a non-vacuum solution deposition process with gelatin. The SOCs with the thin-film ceria interlayers achieved superior electrochemical performance both in the fuel cell (FC) and the electrolysis cell (EC) mode (~3.5W/cm2 and ~2.1A/cm2 at 750°C for the FC and EC modes, respectively) compared to the SOC with a conventional porous and thick interlayer. The mechanistic analyses showed that the thin-film interlayer provides a much shorter route for oxygen ionic conduction and more active sites for oxygen reduction reaction (ORR) and oxygen evolution reaction (ORR) at the interface compared to the porous interlayer. Our results suggest that the thin-film doubly-doped ceria interlayer fabricated using the gelatin-assisted process has a high potential for development of high-performance SOCs.

Bias-voltage photoconductance and photoluminescence for the determination of silicon-dielectric interface properties in SiO2/Al2O3 stacks

This paper presents an advanced measurement method for controlling the surface charge carrier density of passivated silicon wafers during photoconductance and photoluminescence measurements, by employing semitransparent poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) electrodes with an applied bias voltage. This is employed to study and analyze charge carrier dynamics in dielectric layers by measuring their direct influence on effective lifetime. With this method, the carrier population at the surface and the effective carrier lifetimes of n- and p-type samples can be investigated, from which the fixed charge carrier density Qf of the passivation can be extracted. Additionally, the defect density Dit can also be derived from the minimum lifetime values at flatband voltage. In SiO2/Al2O3 stacks with varying SiO2 interlayer thickness, it was shown that by changing the SiO2 thickness, the carrier density Qf can be tuned to a wide range of values, which corresponds to the results obtained in other studies. An increase in interlayer thickness resulted in a decrease in Qf. Varying the SiO2 thickness, the behavior of the respective effective lifetime under bias voltage also changes, exhibiting hysteresis-like effects, which are attributed to additional charges getting trapped at the surface during bias-voltage application. This effect is much more pronounced for samples with a thinner SiO2 layer as well as for the n-type samples. Additionally, the doping type also influences the magnitude of Qf, with p-type samples generally reaching lower absolute values. It was also shown that aging of the samples had a significant effect on the measured Qf, which was increased compared to the initial Qf of the passivation. This effect was more pronounced for the n-type samples. The measurements were realized by a cost-effective and easy-to-use microcontroller-based potentiostat, which can be used as a simple add-on to existing photoconductance or photoluminescence measurement setups.

Thermal interdiffusion, microstructure and contact resistivity of NiOx/Ni/p+ poly-Si layer systems for perovskite/TOPCon tandem solar cells during annealing processes

In a recently published article (Lange et al., 2023) [1], we envisioned and discussed a tandem solar cell concept based on a perovskite/TOPCon architecture in p-i-n configuration, that utilizes a p+/n+ polycrystalline silicon (poly-Si) tunnel junction and NiOx as hole transport material of the perovskite top cell. A direct contact of NiOx to p+ poly-Si is inevitable in such a device. We investigated that junction and reported how the contact resistivity of the NiOx/p+ poly-Si junction can be improved by orders of magnitudes by intentionally inserting a nm-thin metallic Ni interlayer at that interface through the formation of nickel silicide.In this contribution, we present comprehensive data on layer stack morphology, composition and interdiffusion and the impact on the measured contact resistivity based on (scanning) transmission electron microscopy (STEM) coupled with energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) of model samples as well as the real contact structures. Diffusion and reaction processes in the NiOx/Ni/p+ poly-Si layer stack are investigated during the annealing in the temperature range between 100 °C and 500 °C for varying Ni interlayer thicknesses of 0, 1.0 and 2.0 nm. Furthermore, two NiOx syntheses routes are investigated: sputter deposition (s-NiOx) and a wet-chemical approach (wc-NiOx). We correlate the improvement of contact resistivity for both systems and temperatures <300 °C in regard to contacts without metallic Ni interlayer with the observation of pinhole formation within the SiOz. We have observed that annealing the Ag/s-NiOx junctions above 300 °C under ambient air leads to rectifying contacts and high contact resistivities due to excessive interdiffusion of Ni, O and Ag.

Influence Analysis of Liquefiable Interlayer on Seismic Response of Underground Station Structure

To study the influence law of the seismic response of underground station structures at liquifiable interlayer sites, a two-dimensional numerical model of the interaction between the soil and station structure was established based on the finite difference software FLAC3D. The nonlinear dynamic response of the station structure located at the liquifiable interlayer site was analyzed considering the location distribution, relative density, and thickness of the liquifiable interlayer. The results show that the deformation of the structure is greatest when the liquifiable interlayer is distributed on both sides of the station side walls, while the interlayer has an energy-dissipating and damping effect on the upper station structure when it is located at the bottom of the structure. The lower the relative density of the liquifiable interlayer is, the stronger the internal dynamic response of the structure will be, and the more unfavorable it will be to the seismic resistance of the structure. When the liquefiable interlayer is only present in the lateral foundation of the station, an increase in its thickness results in a stronger shear effect on the structure and a higher probability of damage. However, when the thickness of the liquifiable interlayer reaches a point where the entire station is placed within it, the lateral force and deformation of the structure are significantly reduced.