Relevant bibliographies by topics / Ge/Si ratios

Academic literature on the topic 'Ge/Si ratios'

Author: Grafiati

Published: 10 December 2022

Last updated: 29 January 2023

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Journal articles on the topic "Ge/Si ratios"

Wang, Yuchen, Tong Zhao, Zhifang Xu, Huiguo Sun, and Jiangyi Zhang. "Ge/Si Ratio of River Water in the Yarlung Tsangpo: Implications for Hydrothermal Input and Chemical Weathering." Water 14, no. 2 (January 10, 2022): 181. http://dx.doi.org/10.3390/w14020181.

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Germanium/Silicon (Ge/Si) ratio is a common proxy for primary mineral dissolution and secondary clay formation yet could be affected by hydrothermal and anthropogenic activities. To decipher the main controls of riverine Ge/Si ratios and evaluate the validity of the Ge/Si ratio as a weathering proxy in the Tibetan Plateau, a detailed study was presented on Ge/Si ratios in the Yarlung Tsangpo River, southern Tibetan Plateau. River water and hydrothermal water were collected across different climatic and tectonic zones, with altitudes ranging from 800 m to 5000 m. The correlations between TDS (total dissolved solids) and the Ge/Si ratio and Si and Ge concentrations of river water, combined with the spatial and temporal variations of the Ge/Si ratio, indicate that the contribution of hydrothermal water significantly affects the Ge/Si ratio of the Yarlung Tsangpo River water, especially in the upper and middle reaches. Based on the mass balance calculation, a significant amount of Ge (11–88%) has been lost during its transportation from hydrothermal water to the river system; these could result from the incorporation of Ge on/into clays, iron hydroxide, and sulfate mineral. In comparison, due to the hydrothermal input, the average Ge/Si ratio in the Yarlung Tsangpo River is a magnitude order higher than the majority of rivers over the world. Therefore, evaluation of the contribution of hydrothermal sources should be considered when using the Ge/Si ratio to trace silicate weathering in rivers around the Tibetan Plateau.

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Zhao, Dandan, Yang Cui, Jing Li, and Lin Zhang. "Atomic Simulations of Si@Ge and Ge@Si Nanowires for Mechanical and Thermal Properties." Crystals 12, no. 10 (October 13, 2022): 1447. http://dx.doi.org/10.3390/cryst12101447.

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Molecular dynamics simulations using Tersoff potential were performed in order to study the evolution of the atomic packing structures, loading states on the atoms, and tensile tests, as well as the thermal properties of Si/Ge core–shell nanowires with different core–shell structures and ratios at different temperatures. Potential energy and pair distribution functions indicate the structural features of these nanowires at different temperatures. During uniaxial tensile testing along the wire axis at different temperatures, different stages including elasticity, plasticity, necking, and fractures are characterized through stress–strain curves, and Young’s modulus, as well as tensile strength, are obtained. The packing patterns and Lode–Nadai parameters reveal the deformation evolution and different distributions of loading states at different strains and temperatures. The simulation results indicate that as the temperature increases, elasticity during the stretching process becomes less apparent. Young’s modulus of the Si/Ge core–shell nanowires at room temperature show differences with changing core–shell ratios. In addition, the Lode–Nadai parameters and atomic level pressures show the differences of these atoms under compression or tension. Temperature and strain significantly affects the pressure distribution in these nanowires. The phonon density of states, when varying the composition and strain, suggest different vibration modes at room temperature. The heat capacities of these nanowires were also determined.

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Wang, L. C., B. Zhang, F. Fang, E. D. Marshall, S. S. Lau, T. Sands, and T. F. Kuech. "An investigation of a nonspiking Ohmic contact to n-GaAs using the Si/Pd system." Journal of Materials Research 3, no. 5 (October 1988): 922–30. http://dx.doi.org/10.1557/jmr.1988.0922.

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A low-resistance nonspiking Ohmic contact to n-GaAs is formed via solid-state reactions utilizing the Si/Pd/GaAs system. Samples with Si to Pd atomic ratios greater than 0.65 result in specific contact resistivity of the order of 10−6 Ω cm2, whereas samples with atomic ratios less than 0.65 yield higher specific contact resistivities or rectifying contacts. Rutherford backscattering spectrometry, cross-sectional transmission electron microscopy, and electron diffraction patterns show that a Pd, Si layer is in contact with GaAs with excess Si on the surface after the Ohmic formation annealing. This observation contrasts with that on a previously studied Ge/Pd/GaAs contact where Ohmic behavior is detected after transport of Ge through PdGe to the interface with GaAs. Comparing the Ge/Pd/GaAs system with the present Si/Pd/GaAs system suggests that a low barrier heterojunction between Ge and GaAs is not the primary reason for Ohmic contact behavior. Low-temperature measurements suggest that Ohmic behavior results from tunneling current transport mechanisms. A regrowth mechanism involving the formation of an n+ GaAs surface layer is proposed to explain the Ohmic contact formation.

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Wu, Zi-Qin, and Bin Zheng. "Fractal formation in Al/Ge bilayer films after annealing." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 212–13. http://dx.doi.org/10.1017/s0424820100174199.

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The temperature of crystallization of amorphous semiconductor films contacted with metal film is much lower than that of isolated amorphous films. This phenomenon is called metal-enhanced crystallization. In our previous works many fractals were formed after crystallization in bilayer films Pd/Si, Au/Ge and Ag/Ge. Based on TEM observation a mechanism of random successive nucleation was proposed to simulate the fractal formation in Pd/Si films. In this paper the fractal formation in Al/Ge films with different thickness ratios of Al and Ge is reported.At first Ge and then Al were evaporated onto fresh cloven NaCl in ordinary high vacuum without breaking the vacuum. Thicknesses of Ge and Al were obtained from masses of Ge and Al used according to the formula of point evaporation source as follows:

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Kots, Pavel A., Alexander V. Kurkin, Vitaly L. Sushkevich, Andrew N. Fitch, Vladimir V. Chernyshev, and Irina I. Ivanova. "Synchrotron XRD and NMR evidence of germanium redistribution during silylation of BEC-type germanosilicate." CrystEngComm 19, no. 40 (2017): 5982–88. http://dx.doi.org/10.1039/c7ce01204g.

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Delvigne, Camille, Sophie Opfergelt, Damien Cardinal, Axel Hofmann, and Luc André. "Desilication in Archean weathering processes traced by silicon isotopes and Ge/Si ratios." Chemical Geology 420 (January 2016): 139–47. http://dx.doi.org/10.1016/j.chemgeo.2015.11.007.

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Yang, Shuying, Munir Humayun, and Vincent J. M. Salters. "Elemental constraints on the amount of recycled crust in the generation of mid-oceanic ridge basalts (MORBs)." Science Advances 6, no. 26 (June 2020): eaba2923. http://dx.doi.org/10.1126/sciadv.aba2923.

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Mid-oceanic ridge basalts (MORBs) are depleted in incompatible elements, but ridge segments far from mantle plumes frequently erupt chemically enriched MORBs (E-MORBs). Two major explanations of E-MORBs are that these basalts are generated by the melting of entrained recycled crust (pyroxenite) beneath ridges or by the melting of refertilized peridotites. These two hypotheses can be discriminated with compatible element abundances from Sc to Ge, here termed the ScGe elements. Here, we demonstrate that E-MORBs have systematically lower Ge/Si and Sc contents and slightly higher Fe/Mn and Nb/Ta ratios than depleted MORBs (D-MORBs) due to the mixing of low-degree pyroxenite melts. The Ge/Si ratio is a new tracer that effectively discriminates between melts derived from peridotite sources and melts derived from mixed pyroxenite-peridotite sources. These new data are used to estimate the distribution of pyroxenite in the mantle sources of global MORB segments.

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GUO, CAIHONG, JIHONG ZHENG, KUN GUI, MENGHUA ZHANG, and SONGLIN ZHUANG. "OPTIMIZATION AND DESIGN OF 2D HONEYCOMB LATTICE PHOTONIC CRYSTAL MODULATED BY LIQUID CRYSTALS." Modern Physics Letters B 27, no. 31 (December 3, 2013): 1350233. http://dx.doi.org/10.1142/s0217984913502333.

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Photonic crystals (PCs) with infiltrating liquid crystals (LCs) have many potential applications because of their ability to continuously modulate the band-gaps. Using the plane-wave expansion method (PWM), we simulate the band-gap distribution of 2D honeycomb lattice PC with different pillar structures (circle, hexagonal and square pillar) and with different filling ratios, considering both when the LC is used as filling pillar material and semiconductors ( Si , Ge ) are used in the substrate, and when the semiconductors ( Si , Ge ) are pillar material and the LC is the substrate. Results show that unlike LC-based triangle lattice PC, optimized honeycomb lattice PC has the ability to generate absolute photonic band-gaps for fabricating optical switches. We provide optimization parameters for LC infiltrating honeycomb lattice PC structure based on simulation results and analysis.

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Cornelis, J. T., B. Delvaux, D. Cardinal, L. André, J. Ranger, and S. Opfergelt. "Tracing mechanisms controlling the release of dissolved silicon in forest soil solutions using Si isotopes and Ge/Si ratios." Geochimica et Cosmochimica Acta 74, no. 14 (July 2010): 3913–24. http://dx.doi.org/10.1016/j.gca.2010.04.056.

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Breiter, Karel, Nina Gardenová, Viktor Kanický, and Tomáš Vaculovič. "Gallium and germanium geochemistry during magmatic fractionation and post-magmatic alteration in different types of granitoids: a case study from the Bohemian Massif (Czech Republic)." Geologica Carpathica 64, no. 3 (June 1, 2013): 171–80. http://dx.doi.org/10.2478/geoca-2013-0018.

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Abstract Contents of Ga and Ge in granites, rhyolites, orthogneisses and greisens of different geochemical types from the Bohemian Massif were studied using inductively coupled plasma mass spectrometry analysis of typical whole-rock samples. The contents of both elements generally increase during fractionation of granitic melts: Ga from 16 to 77 ppm and Ge from 1 to 5 ppm. The differences in Ge and Ga contents between strongly peraluminous (S-type) and slightly peraluminous (A-type) granites were negligible. The elemental ratios of Si/1000Ge and Al/1000Ga significantly decreased during magmatic fraction: from ca. 320 to 62 and from 4.6 to 1.2, respectively. During greisenization, Ge is enriched and hosted in newly formed hydrothermal topaz, while Ga is dispersed into fluid. The graph Al/Ga vs. Y/Ho seems to be useful tool for geochemical interpretation of highly evolved granitoids.

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Dissertations / Theses on the topic "Ge/Si ratios"

Delvigne, Camille. "The Archaean silicon cycle insights from silicon isotopes and Ge/Si ratios in banded iron formations, palaeosols and shales." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209652.

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The external silicon cycle during the Precambrian (4.5-0.5 Ga) is not well understood despite its key significance to apprehend ancient dynamics at the surface of the Earth. In the absence of silicifying organisms, external silicon cycle dramatically differs from nowadays. Our current understanding of Precambrian oceans is limited to the assumption that silicon concentrations were close to saturation of amorphous silica. This thesis aims to bring new insights to different processes that controlled the geochemical silicon cycle during the Archaean (3.8-2.5 Ga). Bulk rock Ge/Si ratio and Si isotopes (δ30Si) offer ideal tracers to unravel different processes that control the Si cycle given their sensitivity to fractionation under near-surface conditions.

First, this study focuses on Si inputs and outputs to ocean over a limited time period (~2.95 Ga Pongola Supergroup, South Africa) through the study of a palaeosol sequence and a contemporaneous banded iron formation. The palaeosol study offers precious clues in the comprehension of Archaean weathering processes and Si transfer from continent to ocean. Desilication and iron leaching were shown to be the major Archaean weathering processes. The occurrence of weathering residues issued of these processes as major component in fine-grained detrital sedimentary mass (shales) attests that identified weathering processes are widely developed and suggest an important dissolved Si flux from continent to the ocean. In parallel, banded iron formations (BIFs), typically characterised by alternation of iron-rich and silica-rich layers, represent an extraordinary record of the ocean-derived silica precipitation throughout the Precambrian. A detailed study of a 2.95 Ga BIF with excellent stratigraphic constraints identifies a seawater reservoir mixed with significant freshwater and very limited amount of high temperature hydrothermal fluids as the parental water mass from which BIFs precipitated. In addition, the export of silicon promoted by the silicon adsorption onto Fe-oxyhydroxides is evidenced. Then, both Si- and Fe-rich layers of BIFs have a common source water mass and a common siliceous ferric oxyhydroxides precursor. Thus, both palaeosols and BIFs highlight the significance of continental inputs to ocean, generally under- estimated or neglected, as well as the close link between Fe and Si cycles.

In a second time, this study explores secular changes in the Si cycle along the Precambrian. During this timespan, the world ocean underwent a progressive decrease in hydrothermal inputs and a long-term cooling. Effects of declining temperature over the oceanic Si cycle are highlighted by increasing δ30Si signatures of both chemically precipitated chert and BIF through time within the 3.8-2.5 Ga time interval. Interestingly, Si isotope compositions of BIF are shown to be kept systematically lighter of about 1.5‰ than contemporaneous cherts suggesting that both depositions occurred through different mechanisms. Along with the progressive increase of δ30Si signature, a decrease in Ge/Si ratios is attributed to a decrease in hydrothermal inputs along with the development of large and widespread desilication during continental weathering.

Le cycle externe du silicium au précambrien (4.5-0.5 Ga) reste mal compris malgré sa position clé dans la compréhension des processus opérant à la surface de la Terre primitive. En l’absence d’organismes sécrétant un squelette externe en silice, le cycle précambrien du silicium était vraisemblablement très différent de celui que nous connaissons à l’heure actuelle. Notre conception de l’océan archéen est limitée à l’hypothèse d’une concentration en silicium proche de la saturation en silice amorphe. Cette thèse vise à une meilleure compréhension des processus qui contrôlaient le cycle géochimique externe du silicium à l’archéen (3.8-2.5 Ga). Dans cette optique, le rapport germanium/silicium (Ge/Si) et les isotopes stables du silicium (δ30Si) représentent des traceurs idéaux pour démêler les différents processus contrôlant le cycle du Si.

Dans un premier temps, cette étude se focalise sur les apports et les exports de silicium à l’océan sur une période de temps restreinte (~2.95 Ga Pongola Supergroup, Afrique du Sud) via l’étude d’un paléosol et d’un dépôt sédimentaire de précipitation chimique quasi-contemporain. L’étude du paléosol apporte de précieux indices quant aux processus d’altération archéens et aux transferts de silicium des continents vers l’océan. Ainsi, la désilicification et le lessivage du fer apparaissent comme des processus majeurs de l’altération archéenne. La présence de résidus issus de ces processus d’altération en tant que composants majeurs de dépôts détritiques (shales) atteste de la globalité de ces processus et suggère des flux significatifs en silicium dissout des continents vers l’océan. En parallèle, les « banded iron formations » (BIFs), caractérisés par une alternance de niveaux riches en fer et en silice, représentent un enregistrement extraordinaire et caractéristique du précambrien de précipitation de silice à partir de l’océan. Une étude détaillée d’un dépôt de BIFs permet d’identifier une contribution importante des eaux douces dans la masse d’eau à partir de laquelle ces roches sont précipitées. Par ailleurs, un mécanisme d’export de silicium via absorption sur des oxyhydroxydes de fer est mis en évidence. Ainsi, les niveaux riches en fer et riche en silice constituant les BIFs auraient une même origine, un réservoir d’eau de mer mélangée avec des eaux douces et une contribution minime de fluides hydrothermaux de haute température, et un même précurseur commun. Dès lors, tant les paléosols que les BIFs mettent en évidence l’importance des apports continentaux à l’océan, souvent négligés ou sous estimés, ainsi que le lien étroit entre les cycles du fer et du silicium.

Dans un second temps, cette étude explore l’évolution du cycle du silicium au cours du précambrien. Durant cette période, l’océan voit les apports hydrothermaux ainsi que sa température diminuer. Dans l’intervalle de temps 3.8-2.5 Ga, les effets de tels changements sur le cycle du silicium sont marqués par un alourdissement progressif des signatures isotopiques des cherts et des BIFs. Le fort parallélisme entre l’évolution temporelle des compositions isotopiques des deux précipités met en évidence leur origine commune, l’océan. Cependant, les compositions isotopiques des BIFs sont systématiquement plus légères d’environ 1.5‰ que les signatures enregistrées pas les cherts. Cette différence est interprétée comme le reflet de mécanismes de dépôts différents. L’alourdissement progressif des compositions isotopiques concomitant à une diminution des rapports Ge/Si reflètent une diminution des apports hydrothermaux ainsi que la mise en place d’une désilicification de plus en plus importante et/ou généralisée lors de l’altération des continents.

Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Vernière, Anne. "Etude de siliciures ternaires : élaboration, propriétés structurales et magnétiques." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10213.

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La partie principale de cette these est consacree a l'etude du compose a fermions lourds uir#2si#2. L'elaboration de monocristaux de grande purete chimique en a ete une etape importante. L'etude et la mise au point d'un nouveau four de tirage czochralski a chauffage tri-arcs sont decrites. Cet appareillage, entierement concu en technique ultravide, a permis la synthese de monocristaux dont les caracteristiques sont meilleures que celles publiees, jusqu'a ce jour. La recherche de nouveaux intermetalliques ternaires proches, dans le diagramme d'equilibre, des composes a fermions lourds de formule generale 1-2-2 est egalement abordee. Trois nouvelles familles de composes ont ete ainsi mises en evidence: m#2t#3x, m#6t#1#6x#7 et m#4t#1#3x#9 (avec m = terre rare ou uranium, t = element de transition et x = silicium ou germanium). Leurs proprietes cristallographiques et physiques ont ete etudiees. Les composes des deux premieres familles sont paramagnetiques de type pauli. Ceux de la troisieme sont, en revanche, tous ordonnes, avec des comportements magnetiques varies. En particulier, nos mesures revelent que u#4ir#1#3si#9 et u#4ir#1#3ge#9 sont deux nouveaux fermions lourds presentant trois transitions magnetiques. Les etudes realisees au cours de ce travail sur uir#2si#2 confirment toute la complexite de ce compose a fermions lourds. Les caracterisations structurales de nos monocristaux ont mis en evidence, pour la premiere fois, l'existence de substitutions d'iridium, par du silicium, sur les deux sites cristallographiques de l'iridium. Les sites de silicium ne sont pas affectes par ce melange, ce qui n'avait jamais ete soupconne. L'influence du recuit et de la stoechiometrie sur les proprietes de uir#2si#2 est egalement presentee. Les etudes par diffraction des neutrons ont montre que uir#2si#2 est antiferromagnetique de type i, que la densite d'aimantation est isotrope et presque uniquement portee par l'uranium et qu'il existe une contribution positive supplementaire attribuable aux electrons de conduction

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Chen, Jiun Hung, and 陳俊宏. "A study of different thickness ratio of Ni、Ge、Si recording film for the write-once bule-ray disk." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/56541514022796813556.

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碩士
中興大學
材料工程學系所
95
Recently﹐the recording of blue-ray write-once disk are mainly made by a-Si/Cu . However﹐due to the advances of the blue-ray disk technique day by day﹐the multi-layers is developed successfully . Therefore﹐we need to further increase the data transfer rate﹐but must change the film structure or use the other material to instead of a-Si . In this study﹐different thickness ratio of a-Ge/Ni、a-Si/a-Ge/Ni and a-Ge/Ni/a-Si recording film by an ion beam assisted deposition(IBAD) system was adopted as the recording layer for the blue-ray write-once disk . Learnt by the experimental result﹐a-Ge(20 nm)/ Ni(1 nm) of recording film only the phase variety of two stages happen, the first stage will have obvious reflectivity increment between 400~440 ℃, the second stage is in the anneal temperature after raising to 500 ℃. Take place the droop of reflectivity. Between 400~440 ℃ reflectivity varieties change for the amorphous Ge crystallization, the reflectivity after 540 ℃ droop for crystallize melting of Ge. Ge(20 nm)/Ni(2 nm) record film has the reflectivity of four stages and changes in the anneal process. The first stage is forming Ni5 Ge3 phase by Ni and Ge inter-diffusion . The variety of second stage is the Ni5 Ge3 and Ge wedge bonding to become NiGe phase. The third stage goes to 390 ℃ for the anneal or so then will have the crystallize germanium . The Ge of the fourth stage occurrence melts to cause of reflectivity droop. And a-Si/a-Ge/Ni at the phase change generated by the anneal temperature of below 500 ℃ all and a-Ge(20 nm)/Ni(2 nm) record film homology, and can generate in above 500 ℃ the second-time reflectivity increment .Suggest being because forming Ni-Si compound cause. So we infer it when can apply blue-ray write-once disk , can because of reflectivity again increase of the phenomemon raise between as-deposition and data write of reflectivity difference. For the a-Ge/Ni/a-Si record film, after 580 ℃ anneal transactions, become the gradient of the reflectivity rising of crystallize Ge reduces after 580 ℃ anneal transactions and occurrence reflectivity again increase of the phenomemon of gradient droop. On the other hand in element depth composition analysis, we find Ni and Ge will produced inter-diffusion but a-Si and a-Ge will be not easy. Also find that the Ni atom will spread into a Si substrate after anneal. In activation energy analysis, the add of amorphous Si layer that can reduce amorphous Ge to change crystallize Ge phase change activation energy but will raise phase variety temperature. The affix of besides amorphous Si layer can also reduce the phase of the Ni5Ge3 phases change activation energy, while the Ni5Ge3 change the activation energy smaller record film forming NiGe phase of the phase change the activation energy is also lower. The residual stress analyzes, understand all as-deposited of record membranes in order to compress stress.If there are more remain stress in the recording films, the heat which is needed to " relaxation " the stress is higher. So that delays the phase change temperature which produce Ni5Ge3.

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Book chapters on the topic "Ge/Si ratios"

Huang, Mengyuan, Kelly Magruder, Yann Malinge, Parastou Fakhimi, Hao-Hsiang Liao, David Kohen, Gregory Lovell, et al. "Germanium on Silicon Avalanche Photodiode for High-Speed fiber Communication." In Photodetectors - Recent Advances, New Perspectives and Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107971.

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Silicon photonics is one of the promising technologies for high-speed optical fiber communications. Among various silicon photonic devices, germanium on silicon avalanche photodiode (Ge/Si APDs) received tremendous attentions because of its superior performance and integration compatibility. In 2016, normal incidence Ge/Si APD demonstrated a NRZ 10−12 sensitivity of −23.5 dBm at 25 Gb/s; more recently, a waveguide-integrated Ge/Si APD receiver presents a 106Gb/s PAM4 sensitivity of −18.9 dBm. These results are best reported performance among all APD-based devices, and these breakthroughs are mainly benefited from Ge/Si APD’s structure and material characteristics. Ge/Si APD adopts a separated charge-absorption-multiplication (SCAM) structure with a pure Ge absorber and an intrinsic Si avalanche layer. Since, Si is one of well-known best avalanche materials with large gain-bandwidth products and low ionization noise ratio, which make Ge/Si APDs demonstrating superior performance at high data rates. Moreover, this Si-based device is manufactured by standard CMOS foundries and is process-compatible with other silicon photonic devices including silicon-based waveguides, demux, hybrid, etc. This advantage simplifies the assembly of photonic systems and makes a large-scale integrated silicon photonic chip possible, which provides compact solutions for high-density communication systems. In this chapter, we review recent progresses on Ge/Si APD structure design, material, and performance.

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Autran Daniela Munteanu, Jean-Luc. "Radiation Response of Group-IV and III-V Semiconductors Subjected to D–D and D–T Fusion Neutrons." In New Advances in Semiconductors [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103047.

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This work focuses on the radiation response of Group IV (Si, Ge, SiC, diamond) and III-V (GaAs, GaN, GaP, GaSb, InAs, InP, InSb, AlAs) semiconductors subjected to D–D (2.45 MeV) and D–T (14 MeV) neutrons. The response of each material has been systematically investigated through a direct calculation using nuclear cross-section libraries, MCNP6, and Geant4 numerical simulations. For the semiconductor materials considered, we have investigated in detail the reaction rates per type of reaction (elastic, inelastic, and nonelastic) and proposed an exhaustive classification and counting of all the neutron-induced events and secondary products as a function of their nature and energy. Several metrics for quantifying the susceptibility of the related semiconductor-based electronics to neutron fusions have been finally considered and discussed.

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Conference papers on the topic "Ge/Si ratios"

Frings, Patrick, Marcus Oelze, Friedhelm von Blanckenburg, and Franziska Schubring. "Quantifying biotic and abiotic Si fluxes in the Critical Zone with Ge/Si ratios along a gradient of erosion rates." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.4653.

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Phillips, Matthew, Olivier Alard, and Stephen Foley. "Application of Ge/Si ratios to ultramafic alkaline rocks using a novel LA-ICP-QQQ-MS method." In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.11565.

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Shinkawa, A., M. Wakiya, Y. Maeda, T. Tsukamoto, and Y. Suda. "Hole-Tunneling Si_1-xGe_x/Si ASDQW RTD with High Resonant Current and High Peak-to-Valley Current Ratio." In 2016 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 2016. http://dx.doi.org/10.7567/ssdm.2016.ps-9-08.

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Lu, Lu, Jinlin Song, Kun Zhou, and Qiang Cheng. "Near-Field Radiative Heat Transfer Between Mie Resonance-Based Metamaterials Made of Coated Nonmagnetic Particles." In ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/mnhmt2019-3998.

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Abstract Near-field radiative heat transfer between Mie resonance-based metamaterials composed of SiC/d-Si (silicon carbide and doped silicon) core/shell particles immersed in aligned nematic liquid crystals are numerically investigated. The metamaterials composed of core/shell particles exhibit superior performances of enhanced heat transfer and obvious modulation effect when compared to that without shell. The underlying mechanism can be explained that the excitation of Fröhlich mode and epsilon-near-zero (ENZ) resonances both contribute to the total heat flux. Modulation of near-field radiative heat transfer can be realized with the host material of aligned nematic liquid crystals. The largest modulation ratio could be achieved as high as 0.45 for metamaterials composed of core/shell SiC/d-Si particles, and the corresponding heat flux is higher than other similar materials such as LiTaO3/GaSb and Ge/LiTaO3. While with the same volume filling fraction, the modulation ratio of that composed of SiC particles is only 0.2. We show that the core/shell nanoparticles dispersed liquid crystals (NDLCs) have a great potential in enhancing the near-field radiative heat transfer in both the p and s polarizations with the radii of 0.65 μm, and Mie-metamaterials are shown for the first time to modulate heat flux within sub-milliseconds.

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Musho, T. D., and D. G. Walker. "Coupled Non-Equilibrium Green’s Function (NEGF) Electron-Phonon Interaction in Thermoelectric Materials." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65786.

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Over the last decade, nano-structured materials have shown a promising avenue for enhancement of the thermoelectric figure of merit. These performance enhancements in most cases have been a direct result of selectively modifying certain geometric attributes that alter the thermal or electrical transport in a desirable fashion. More often, models used to study the electrical and/or thermal transport are calculated independent of each other. However, studies have suggested electrical and thermal transport are intimately linked at the nanoscale. This provides an argument for a more rigorous treatment of the physics in an effort to capture the response of both electrons and phonons simultaneously. A simulation method has been formulated to capture the electron-phonon interaction of nanoscale electronics through a coupled non-equilibrium Greens function (NEGF) method. This approach is unique because the NEGF electron solution and NEGF phonon solution have only been solved independently and have never been coupled to capture a self-consistent inelastic electron-phonon scattering. One key aspect of this formalism is that the electron and phonon description is derived from a quantum point of view and no correction terms are necessary to account for the probabilistic nature of the transport. Additionally, because the complete phonon description is solved, scattering rates of individual phonon frequencies can be investigated to determine how electron-phonon scattering of particular frequencies influences the transport. This computational method is applied to the study of Si/Ge nanostructured superlattice thermoelectric materials.

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Liang, Zhi, and Hai-Lung Tsai. "Effect of Interlayer Between Semiconductors on Interfacial Thermal Transport." In ASME 2012 Third International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/mnhmt2012-75273.

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Due to the high surface–to–volume ratio in nanostructured components and devices, thermal transport across the solid–solid interface strongly affects the overall thermal behavior. Materials such as Si, Ge, SiO2 and GaAs are widely used in advanced semiconductor devices. These materials may have differences in both crystal structure and Debye temperature. We have shown that the thermal transport across such interfaces can be improved by inserting an interlayer between the two confining solids. If the two confining solids are similar in crystal structure and lattice constant but different in Debye temperature, it is predicted from the molecular dynamics modeling that an over 50% reduction of the thermal boundary resistance can be achieved by inserting a 1– to 2–nm–thick interlayer which has similar crystal structure and lattice constant as the two solids. In this case, the Debye temperature of the optimized interlayer is approximately the square root of the product of the Debye temperatures of the two solids. However, if the interlayer has large lattice mismatches with the two confining solids, a thin disordered layer is formed in the solid and in the interlayer adjacent to their interface. Such a disordered layer can distort the phonon density of states at the interface and strongly affects the interfacial phonon transport. In this case, it is found that a 70% reduction of the thermal boundary resistance can be achieved if the lattice constant of the interlayer is smaller than that of the two solids and the Debye temperature of the interlayer is approximately the average of the Debye temperatures of the two solids. On the other hand, if the two solids have a large difference in both lattice constant and Debye temperature, the optimized interlayer should have a lattice constant near the average of the lattice constants of the two solids. For this case, an over 60% reduction of the thermal boundary resistance can be achieved if the Debye temperature of the interlayer is equal to or slightly higher than the square root of the product of the Debye temperatures of the two solids. The calculated phonon density of states shows that the distorted phonon spectra induced by large lattice mismatches are generally broader than the phonon spectra of the corresponding undistorted case. The broader interfacial phonon spectra increase the overlap between the phonon spectra of the two solids at the interface which leads to improved thermal boundary transport.

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Stevens, Robert J., Pamela M. Norris, and Arthur W. Lichtenberger. "Experimental Determination of the Relationship Between Thermal Boundary Resistance and Non-Abrupt Interfaces and Electron-Phonon Coupling." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56556.

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Understanding thermal boundary resistance (TBR) is becoming increasingly important for the thermal management of micro and optoelectronic devices. The current understanding of room temperature TBR is often not adequate for the thermal design of tomorrow’s complex micro and nano devices. Theories have been developed to explain the resistance to energy transport by phonons across interfaces. The acoustic mismatch model (AMM) [1, 2], which has had success at explaining low temperature TBR, does not account for the high frequency phonons and imperfect interfaces of real devices at room temperature. The diffuse mismatch model (DMM) was developed to account for real surfaces with higher energy phonons [3, 4]. DMM assumes that all phonons incident on the interface from both sides are elastically scattered and then emitted to either side of the interface. The probability that a phonon is emitted to a particular side is proportional to the phonon density of states of the two interface materials. Inherent to the DMM is that the transport is independent of the interface structure itself and is only dependent on the properties of the two materials. Recent works have shown that the DMM does not adequately capture all the energy transport mechanisms at the interface [5, 6]. In particular, the DMM under-predicts transport across interfaces between non Debye-like materials, such at Pb and diamond, by approximately an order of magnitude. The DMM also tends to over-predict transport for interfaces made with materials of similar acoustic properties, Debye-like materials. There have been several explanations and models developed to explain the discrepancies between the mismatch models and experimental data. Some of these models are based on modification of the AMM and DMM [7–9]. Other works have utilized lattice-dynamical modeling to calculate phonon transmission coefficients and thermal boundary conductivities for abrupt and disordered interfaces [3, 6, 10–13]. Recent efforts to better understand room temperature TBR have utilized molecular dynamics simulations to account for more realistic anharmonic materials and inelastic scattering [14–18]. Models have also been developed to account for electron-phonon scattering and its effect on the thermal boundary conductance for interfaces with one metal side [19–22]. Although there have been numerous thermal boundary resistance theoretical developments since the introduction of the AMM, there still is not an unifying theory that has been well validated for high temperature solid-solid interfaces. Most of the models attempt to explain some of the experimental outliers, such as Pb/diamond and TiN/MgO interfaces [6, 23], but have not been fully tested for a range of experimental data. Part of the problem lies in the fact that very little reliable data is available, especially data that is systematically taken to validate a particular model. To this end, preliminary measurements of TBR are being made on a series of metal on non-metal substrate interfaces using a non-destructive optical technique, transient thermal reflectance (TTR) described in Stevens et al. [5]. Initial testing examines the impact of different substrate preparation and deposition conditions on TBR for Debye-like interfaces for which TBR should be small for clean and abrupt interfaces. Variables considered include sputter etching power and duration, electron beam source clean, and substrate temperature control. The impact of alloying and non-abrupt interfaces on the TBR is examined by fabricating interfaces of both Debye-like and non Debye-like interfaces followed by systematically measuring TBR and altering the interfaces by annealing the samples to increase the diffusion depths at the interfaces. Inelastic electron scattering at the interface has been proposed by Hubermann et al. and Sergeev to decrease TBR at interfaces [19–21]. Two sets of samples are prepared to examine the electron-phonon connection to improved thermal boundary conductance. The first consists of thin Pt and Ag films on Si and sapphire substrates. Pt and Ag electron-phonon coupling factors are 60 and 3.1×1016 W/m3K respectively. Both Pt and Ag have similar Debye temperatures, so electron scattering rates can be examined without much change in acoustic effects. The second electron scattering sample series consist of multiple interfaces fabricated with Ni, Ge, and Si to separate the phonon and electron portions of thermal transport. The experimental data is compared to several of the proposed theories.

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