scholarly journals An Overview of Nano Multilayers as Model Systems for Developing Nanoscale Microstructures

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 382
Author(s):  
Chelsea D. Appleget ◽  
Juan Sebastian Riano ◽  
Andrea M. Hodge
Keyword(s):  
Binary Systems ◽  
Material Selection ◽  
Layer Structure ◽  
Interface Energy ◽  
Multilayer Films ◽  
Model Systems ◽  
Global Evaluation ◽  
Material System ◽  
Local Composition ◽  
Global And Local

The microstructural transformations of binary nanometallic multilayers (NMMs) to equiaxed nanostructured materials were explored by characterizing a variety of nanoscale multilayer films. Four material systems of multilayer films, Hf-Ti, Ta-Hf, W-Cr, and Mo-Au, were synthesized by magnetron sputtering, heat treated at 1000 °C, and subsequently characterized by transmission electron microscopy. Binary systems were selected based on thermodynamic models predicting stable nanograin formation with similar global compositions around 20–30 at.%. All NMMs maintained nanocrystalline grain sizes after evolution into an equiaxed structure, where the systems with highly mobile incoherent interfaces or higher energy interfaces showed a more significant increase in grain size. Furthermore, varying segregation behaviors were observed, including grain boundary (GB) segregation, precipitation, and intermetallic formation depending on the material system selected. The pathway to tailored microstructures was found to be governed by key mechanisms and factors as determined by a film’s initial characteristics, including global and local composition, interface energy, layer structure, and material selection. This work presents a global evaluation of NMM systems and demonstrates their utility as foundation materials to promote tailored nanomaterials.

scholarly journals Evaluating Approximations and Heuristic Measures of Integrated Information

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 525 ◽  
Author(s):  
André Sevenius Nilsen ◽  
Bjørn Erik Juel ◽  
William Marshall
Keyword(s):  
Binary Systems ◽  
Initial Conditions ◽  
Transition Probability ◽  
Ground Truth ◽  
Transition Probability Matrix ◽  
Efficient Estimation ◽  
Model Systems ◽  
Practical Applications ◽  
Linear Threshold ◽  
Integrated Information

Integrated information theory (IIT) proposes a measure of integrated information, termed Phi (Φ), to capture the level of consciousness of a physical system in a given state. Unfortunately, calculating Φ itself is currently possible only for very small model systems and far from computable for the kinds of system typically associated with consciousness (brains). Here, we considered several proposed heuristic measures and computational approximations, some of which can be applied to larger systems, and tested if they correlate well with Φ. While these measures and approximations capture intuitions underlying IIT and some have had success in practical applications, it has not been shown that they actually quantify the type of integrated information specified by the latest version of IIT and, thus, whether they can be used to test the theory. In this study, we evaluated these approximations and heuristic measures considering how well they estimated the Φ values of model systems and not on the basis of practical or clinical considerations. To do this, we simulated networks consisting of 3–6 binary linear threshold nodes randomly connected with excitatory and inhibitory connections. For each system, we then constructed the system’s state transition probability matrix (TPM) and generated observed data over time from all possible initial conditions. We then calculated Φ, approximations to Φ, and measures based on state differentiation, coalition entropy, state uniqueness, and integrated information. Our findings suggest that Φ can be approximated closely in small binary systems by using one or more of the readily available approximations (r > 0.95) but without major reductions in computational demands. Furthermore, the maximum value of Φ across states (a state-independent quantity) correlated strongly with measures of signal complexity (LZ, rs = 0.722), decoder-based integrated information (Φ*, rs = 0.816), and state differentiation (D1, rs = 0.827). These measures could allow for the efficient estimation of a system’s capacity for high Φ or function as accurate predictors of low- (but not high-)Φ systems. While it is uncertain whether the results extend to larger systems or systems with other dynamics, we stress the importance that measures aimed at being practical alternatives to Φ be, at a minimum, rigorously tested in an environment where the ground truth can be established.

Novel Structured Electrolyte for All-Solid-State Lithium Ion Batteries

2015 ◽  
Author(s):  
Wei Liu ◽  
Ryan Milcarek ◽  
Kang Wang ◽  
Jeongmin Ahn
Keyword(s):  
Solid State ◽  
Lithium Ion Batteries ◽  
Solid Electrolytes ◽  
Material Selection ◽  
Layer Structure ◽  
Gel Polymer Electrolyte ◽  
Lithium Ion ◽  
Interfacial Resistance ◽  
Solid State Electrolyte ◽  
Ceramic Electrolyte

In this study, a multi-layer structure solid electrolyte (SE) for all-solid-state electrolyte lithium ion batteries (ASSLIBs) was fabricated and characterized. The SE was fabricated by laminating ceramic electrolyte Li1.3Al0.3Ti1.7(PO4)3 (LATP) with polymer (PEO)10-Li(N(CF3SO2)2 electrolyte and gel-polymer electrolyte of PVdF-HFP/ Li(N(CF3SO2)2. It is shown that the interfacial resistance is generated by poor contact at the interface of the solid electrolytes. The lamination protocol, material selection and fabrication method play a key role in the fabrication process of practical multi-layer SEs.

scholarly journals Study of First Principles of Mg-Si Binary Systems as Precipitates from T6 Heat Treatment of AL-MG-SI ALLOYS

2020 ◽  
Vol 10 (01) ◽  
pp. 16
Author(s):  
Deni Haryadi ◽  
Haris Rudianto
Keyword(s):  
Heat Treatment ◽  
First Principles ◽  
Density Functional ◽  
Binary Systems ◽  
Pure Aluminum ◽  
Density Functional Theory Calculations ◽  
Interface Energy ◽  
Strength Increase ◽  
Functional Theory ◽  
Interfacial Energies

<p>One of the purposes adding the two main alloying elements Si and Mg in small quantities (≈ 1%) on Aluminum is to form strengthening precipitates in aluminium alloy, which typically contribute with a fivefold strength increase from pure aluminum. In the last decades, the investigation has begun to understand the structure and formation of the different phases during heat treatment. An important precipitate in Al-Mg-Si Alloy is β" and β.  when the Precipitate β is created after β" is that the strength suddenly drops and the alloy is said to be overaged. By means of a first-principles supercell approach and density functional theory calculations, this research studied precipitate energy and interface energy of precipitate β" and β. Results show that precipitate β have precipitate energy higher then β" but have interface energy lowers then β". And each low energy interface was found possesses interface with the Al matrix is fully incoherent. The final result of calculation and simulation values for the interfacial energies, precipitate energies and strain energies that can be used in future predictions of the characteristic precipitate.</p>

scholarly journals Advances in Filament Structure of 3D Bioprinted Biodegradable Bone Repair Scaffolds

2021 ◽  
Vol 7 (4) ◽  
pp. 426
Author(s):  
Chengxiong Lin ◽  
Yaocheng Wang ◽  
Zhengyu Huang ◽  
Tingting Wu ◽  
Weikang Xu ◽  
...  
Keyword(s):  
Performance Optimization ◽  
Bone Repair ◽  
Material Selection ◽  
Layer Structure ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Single Layer ◽  
Biological Properties ◽  
Filament Structure ◽  
High Standards

Conventional bone repair scaffolds can no longer meet the high standards and requirements of clinical applications in terms of preparation process and service performance. Studies have shown that the diversity of filament structures of implantable scaffolds is closely related to their overall properties (mechanical properties, degradation properties, and biological properties). To better elucidate the characteristics and advantages of different filament structures, this paper retrieves and summarizes the state of the art in the filament structure of the three-dimensional (3D) bioprinted biodegradable bone repair scaffolds, mainly including single-layer structure, double-layer structure, hollow structure, core-shell structure and bionic structures. The eximious performance of the novel scaffolds was discussed from different aspects (material composition, ink configuration, printing parameters, etc.). Besides, the additional functions of the current bone repair scaffold, such as chondrogenesis, angiogenesis, anti-bacteria, and anti-tumor, were also concluded. Finally, the paper prospects the future material selection, structural design, functional development, and performance optimization of bone repair scaffolds.

Effects of Low CTE Materials on Thermal Deformation of Organic Substrates in Flip Chip Package Application

2015 ◽  
Author(s):  
Hiroyuki Mori ◽  
Sayuri Kohara ◽  
Keishi Okamoto ◽  
Hirokazu Noma ◽  
Kazushige Toriyama
Keyword(s):  
Finite Element ◽  
Thermal Deformation ◽  
Flip Chip ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Layer Structure ◽  
Surface Profile ◽  
Organic Substrates ◽  
Convex Shape ◽  
Typical Application

Coefficient of thermal expansion (CTE) characteristic of organic materials for substrates in flip chip package application demanded by semiconductor package requirements is becoming lower than ever. In general, height restrictions are imposed on package-on-package (PoP) devices in mobile applications. One should hence establish a tight budget on the height variation in manufacturing of the devices. Given such background, a lowering of the CTE characteristic of package substrates is an attractive solution for reducing package deformation upon manufacturing, since it contributes to minimize CTE mismatch of the substrates with silicon chips. In large-die flip chip applications such as high-end processors, a lower CTE substrate can mitigate mechanical stress not only on low-k layers in back end of the line (BEOL) underneath the chip bumps, but also on underfill layers during thermal cycling. Therefore an introduction of lower CTE materials in organic substrates is becoming essential for future applications of electronic devices. In this paper, thermal deformation behaviors of organic substrates associated with lowering of the CTEs of their constituent materials are analyzed by finite element analysis (FEA). The analyses are done on a 3-2-3 build-up layer structure substrate in order to focus onto typical application specific integrated circuit (ASIC) products. A finite element model for a test substrate is constructed by a method in which the substrate is divided into sections according to its circuitry patterns so that the lateral inhomogeneity of mechanical property is taken into account. The finite element analyses using the model showed that the package warpage decreases with lowering of the effective CTE of the substrate, but the warpage of the substrate itself increases and its surface profile changes from a concave shape to a convex shape. The analysis result of substrate warpage variation with the build-up material’s CTE showed that the selection of build-up materials with appropriate material properties can contribute to reduce the substrate warpage. The analysis also showed that the adverse impact to the substrate’s CTE reduction by such material selection is limited.

Preparation and microstructure of SrCuO2/(Sr0.5Ca0.5)CuO2 epitaxial multilayers with the infinite-layer structure

1994 ◽  
Vol 9 (8) ◽  
pp. 1961-1966 ◽  
Author(s):  
Toshifumi Satoh ◽  
Hideaki Adachi ◽  
Yo Ichikawa ◽  
Kentaro Setsune ◽  
Kiyotaka Wasa
Keyword(s):  
Layer Structure ◽  
Rf Magnetron Sputtering ◽  
Multilayer Films ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Infinite Layer ◽  
Transmission Electron ◽  
Epitaxial Multilayers ◽  
Secondary Ion ◽  
Modulation Wavelength

Multilayer thin films of SrCuO2/(Sr0.5Ca0.5)CuO2 with an infinite-layer structure have been prepared on (100) SrTiO3 single crystals by multitarget rf magnetron sputtering. The structural analyses of the multilayers were carried out by means of x-ray diffraction (XRD), secondary ion-mass-spectroscopy (SIMS), and transmission electron microscopy (TEM). Heteroepitaxial growth of the SrCuO2 and (Sr0.5Ca0.5)CuO2 layers was confirmed to be with the c-axis perpendicular to the (100) SrTiO3 surface. The XRD and SIMS measurements revealed that the compositional modulations of the multilayer films were successfully constructed as we designed. However, in the TEM images, there existed planar dislocations parallel to the ac- and bc-planes, which went across the boundaries of the SrCuO2 and (Sr0.5Ca0.5)CuO2 layers. The resistivity of the multilayer films showed semiconductor-like behavior with temperature, and there was no relation between electric properties and modulation wavelength.

scholarly journals Управление магнитными свойствами многослойных периодических структур на основе Co/Pt

2019 ◽  
Vol 89 (11) ◽  
pp. 1674
Author(s):  
Д.А. Татарский ◽  
Н.С. Гусев ◽  
В.Ю. Михайловский ◽  
Ю.В. Петров ◽  
С.А. Гусев
Keyword(s):  
Magnetic Anisotropy ◽  
Vacuum Annealing ◽  
Periodic Structures ◽  
Layer Structure ◽  
Perpendicular Magnetic Anisotropy ◽  
Multilayer Films ◽  
Transmission Electron ◽  
Plane Anisotropy ◽  
Helium Ion ◽  
Different Temperatures

The possibility of controlling the magnetic properties of multilayer periodic structures with perpendicular magnetic anisotropy based on cobalt and platinum films is investigated. Multilayer films consisting of layers 0.5–1.0 nm thick undergo to two types of impacts: vacuum annealing at different temperatures and irradiation with beams of helium ions. It was shown using transmission electron microscopy that irradiation with He+ ions with an energy of 30 keV leads to the mixing of the material of the layers. But the layer structure of the film is preserved during vacuum annealing. As a result of thermal annealing, the coercive force of the structure increases significantly. The coercivity of the helium ion irradiated films decreases to a change in the type of anisotropy from the perpendicular magnetic anisotropy to the “easy plane” anisotropy.

scholarly journals Realization of III-Nitride c-Plane microLEDs Emitting from 470 to 645 nm on Semi-Relaxed Substrates Enabled by V-Defect-Free Base Layers

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1168
Author(s):  
Ryan C. White ◽  
Michel Khoury ◽  
Matthew S. Wong ◽  
Hongjian Li ◽  
Cheyenne Lynsky ◽  
...  
Keyword(s):  
Layer Structure ◽  
Emission Spectra ◽  
Chemical Vapor ◽  
Visible Spectrum ◽  
Lattice Parameter ◽  
Base Layer ◽  
Organic Chemical ◽  
Material System ◽  
Light Spectrum ◽  
Wide Range

We examine full InGaN-based microLEDs on c-plane semi-relaxed InGaN substrates grown by metal organic chemical vapor deposition (MOCVD) that operate across a wide range of emission wavelengths covering nearly the entire visible spectrum. By employing a periodic InGaN base layer structure with high temperature (HT) GaN interlayers on these semi-relaxed substrates, we demonstrate robust μLED devices. A broad range of emission wavelengths ranging from cyan to deep red are realized, leveraging the indium incorporation benefit of the relaxed InGaN substrate with an enlarged lattice parameter. Since a broad range of emission wavelengths can be realized, this base layer scheme allows the tailoring of the emission wavelength to a particular application, including the possibility for nitride LEDs to emit over the entire visible light spectrum. The range of emission possibilities from blue to red makes the relaxed substrate and periodic base layer scheme an attractive platform to unify the visible emission spectra under one singular material system using III-Nitride MOCVD.

Properties of Dielectric Thin Films Formed by Laser Evaporation

1983 ◽  
Vol 29 ◽  
Author(s):  
H. Sankur
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Binary Systems ◽  
Evaporation Rate ◽  
High Vacuum ◽  
Optical Devices ◽  
Laser Evaporation ◽  
Material System ◽  
Optical And Electrical Properties ◽  
Dielectric Thin Films

ABSTRACTThe technique of laser evaporation for the deposition of thin films has been applied to a large class of materials including oxides, fluorides and II-VI semiconductors. The evaporations were performed in high vacuum or under O2 pressures of 10−3 Torr, on several types of substrates, by using CO2 lasers in CW and pulse modes. The thin films thus obtained have been characterized for their structural, optical and electrical properties.Entire ranges of mixtures in several binary systems (e.g., SnO2-SiO2), have been obtained by coevaporation, using mirrors to steer the laser beam among sources.Conditions that affect the stoichiometry and structural properties (laser parameters, background pressure, evaporation rate, substrate temperature) have been established for each material system. Differences in the evaporation behavior of materials under CW and pulsed conditions have been investigated for the case of ZnO. Present and future applications of this technique in the optical devices field are also discussed.

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