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Ma, Lu. "Synthesis and Characterization of Large Area Few-layer MoS2 and WS2 Films." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1388149255.
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Huang, Zhida [Verfasser]. "Characterization and catalytic activity study of SBA-15-supported MoO3, MoS2, Ni or Co promoted MoS2 and Co promoted WS2 / Zhida Huang." Kiel : Universitätsbibliothek Kiel, 2010. http://d-nb.info/1019951621/34.
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Young, Justin R. "Synthesis and Characterization of Novel Two-Dimensional Materials." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468925594.
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Alrobei, Hussein. "Synthesis and Characterization of Alpha-Hematite Nanomaterials for Water-Splitting Applications." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7661.
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The recent momentum in energy research has simplified converting solar to electrical energy through photoelectrochemical (PEC) cells. There are numerous benefits to these PEC cells, such as the inexpensive fabrication of thin film, reduction in absorption loss (due to transparent electrolyte), and a substantial increase in the energy conversion efficiency. Alpha-hematite ([U+F061]-Fe2O3) has received considerable attention as a photoanode for water-splitting applications in photoelectrochemical (PEC) devices. The alpha-hematite ([U+F061]-Fe2O3) nanomaterial is attractive due to its bandgap of 2.1eV allowing it to absorb visible light. Other benefits of [U+F061]-Fe2O3 include low cost, chemical stability and availability in nature, and excellent photoelectrochemical (PEC) properties to split water into hydrogen and oxygen. However, [U+F061]-Fe2O3 suffers from low conductivity, slow surface kinetics, and low carrier diffusion that causes degradation of PEC device performance. The low carrier diffusion of [U+F061]-hematite is related to higher resistivity, slow surface kinetics, low electron mobility, and higher electro-hole combinations. All the drawbacks of [U+F061]-Fe2O3, such as low carrier mobility and electronic diffusion properties, can be enhanced by doping, which forms the nanocomposite and nanostructure films.
In this study, all nanomaterials were synthesized utilizing the sol-gel technique and investigated using Scanning Electron Microscopy (SEM), X-ray Diffractometer (XRD), UV-Visible Spectrophotometer (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), Raman techniques, Particle Analyzer, Cyclic Voltammetry (CV), and Chronoamperometry, respectively. The surface morphology is studied by SEM. X-Ray diffractometer (XRD) is used to identify the crystalline phase and to estimate the crystalline size. FTIR is used to identify the chemical bonds as well as functional groups in the compound. A UV-Vis absorption spectral study may assist in understanding electronic structure of the optical band gap of the material. Cyclic voltammetry and chronoamperometry were used to estimate the diffusion coefficient and study electrochemical activities at the electrode/electrolyte interface.
In this investigation, the [U+F061]-Fe2O3 was doped with various materials such as metal oxide (aluminum, Al), dichalcogenide (molybdenum disulfide, MoS2), and co-catalyst (titanium dioxide, TiO2). By doping or composite formation with different percentage ratios (0.5, 10, 20, 30) of aluminum (Al) containing [U+F061]-Fe2O3, the mobility and carrier diffusion properties of [U+F061]-hematite ([U+F061]-Fe2O3) can be enhanced. The new composite, Al-[U+F061]-Fe2O3, improved charge transport properties through strain introduction in the lattice structure, thus increasing light absorption. The increase of Al contents in [U+F061]-Fe2O3 shows clustering due to the denser formation of the Al-[U+F061]-Fe2O3 particle. The presence of aluminum causes the change in structural and optical and morphological properties of Al-[U+F061]-Fe2O3 more than the properties of the [U+F061]-Fe2O3 photocatalyst. There is a marked variation in the bandgap from 2.1 to 2.4 eV. The structure of the composite formation Al-[U+F061]-Fe2O3, due to a high percentage of Al, shows a rhombohedra structure. The photocurrent (35 A/cm2) clearly distinguishes the enhanced hydrogen production of the Al-[U+F061]-Fe2O3 based photocatalyst.
This work has been conducted with several percentages (0.1, 0.2, 0.5, 1, 2, 5) of molybdenum disulfide (MoS2) that has shown enhanced photocatalytic activity due to its bonding, chemical composition, and nanoparticle growth on the graphene films. The MoS2 material has a bandgap of 1.8 eV that works in visible light, responding as a photocatalyst. The photocurrent and electrode/electrolyte interface of MoS2-[U+F061]-Fe2O3 nanocomposite films were investigated using electrochemical techniques. The MoS2 material could help to play a central role in charge transfer with its slow recombination of electron-hole pairs created due to photo-energy with the charge transfer rate between surface and electrons. The bandgap of the MoS2 doped [U+F061]-Fe2O3 nanocomposite has been estimated to be vary from 1.94 to 2.17 eV. The nanocomposite MoS2-[U+F061]-Fe2O3 films confirmed to be rhombohedral structure with a lower band gap than Al-[U+F061]-Fe2O3 nanomaterial. The nanocomposite MoS2-[U+F061]-Fe2O3 films revealed a more enhanced photocurrent (180 μA/cm2) than pristine [U+F061]-Fe2O3 and other transition metal doped Al-[U+F061]-Fe2O3 nanostructured films.
The p-n configuration has been used because MoS2 can remove the holes from the n-type semiconductor by making a p-n configuration. The photoelectrochemical properties of the p-n configuration of MoS2-α-Fe2O3 as the n-type and ND-RRPHTh as the p-type deposited on both n-type silicon and FTO-coated glass plates. The p-n photoelectrochemical cell is stable and allows for eliminating the photo-corrosion process. Nanomaterial-based electrodes [U+F061]-Fe2O3-MoS2 and ND-RRPHTh have shown an improved hydrogen release compared to [U+F061]-Fe2O3, Al-[U+F061]-Fe2O3 and MoS2-[U+F061]-Fe2O3 nanostructured films in PEC cells. By using p-n configuration, the chronoamperometry results showed that 1% MoS2 in MoS2-[U+F061]-Fe2O3 nanocomposite can be a suitable structure to obtain a higher photocurrent density. The photoelectrochemical properties of the p-n configuration of MoS2-α-Fe2O3 as n-type and ND-RRPHTh as p-type showed 3-4 times higher (450 A/cm2) in current density and energy conversion efficiencies than parent electrode materials in an electrolyte of 1M of NaOH in PEC cells.
Titanium dioxide (TiO2) is known as one of the most explored electrode materials due to its physical and chemical stability in aqueous materials and its non-toxicity. TiO2 has been investigated because of the low cost for the fabrication of photoelectrochemical stability and inexpensive material. Incorporation of various percentages (2.5, 5, 16, 25, 50) of TiO2 in Fe2O3 could achieve better efficiencies as the photoanode by enhancing the electron concentration and low combination rate, and both materials can have a wide range of wavelength which could absorb light in both UV and visible spectrum ranges. TiO2 doped with [U+F061]-Fe2O3 film was shown as increasing contacting area with the electrolyte, reducing e-h recombination and shift light absorption along with visible region. The [U+F061]-Fe2O3-TiO2 nanomaterial has shown a more enhanced photocurrent (800 μA/cm2) than metal doped [U+F061]-Fe2O3 photoelectrochemical devices.
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Singh, Harpal. "An Investigation of Material Properties and Tribological Performance of Magnetron Sputtered Thin Film Coatings." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1449850005.
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Gomes, Francis Oliver Vinay [Verfasser], Veit [Akademischer Betreuer] Wagner, Veit [Gutachter] Wagner, Thomas [Gutachter] Heine, and Ralf [Gutachter] Anselmann. "Film growth and characterization of solution processed MoS2 semiconductor films for thin film transistors / Francis Oliver Vinay Gomes ; Gutachter: Veit Wagner, Thomas Heine, Ralf Anselmann ; Betreuer: Veit Wagner." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2019. http://d-nb.info/1190888181/34.
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Swati, Swati, Richard Sante, and Aruna Kilaru. "Characterization of Arachidonylethanolamide Metabolic Pathway in Moss." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/4803.
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Arachidonylethanolamide (AEA) is a bioactive lipid ligand for mammalian cannabinoid receptors (CB). Thus far, AEA was reported to occur only in animals and was shown to regulate a wide range of physiological responses. Our recent fi nding of the occurrence of AEA in moss has led us hypothesize that AEA might mediate stress responses in plants, similar to that in animals. In mammals, AEA is generated from hydrolysis of N-acylphosphatidylethanolamine (NAPE) by a NAPE-specifi c phospholipase D (NAPE-PLD), and degraded by a fatty acid amide hydrolase (FAAH) and this metabolic pathway is highly conserved among eukaryotes. Here, using in silico approach, putative genes encoding for AEA pathway enzymes, were identifi ed in moss. Full-length coding sequences for putative NAPE-PLD and FAAH were isolated from Physcomitrella patens and were cloned and expressed into a heterologous expression vector. Biochemical characterization of AEA pathway enzymes is underway and is expected to lead to generation of AEA metabolite mutants in moss. Such mutants will allow for elucidation of the role of AEA in development of moss and mediating stress responses. Overall, this study will provide novel insights into functional and evolutionary role of lipid-mediated signaling in plants.
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Swati, Swati, Richard Sante, Brent Kinser, and Aruna Kilaru. "Characterization of Anandamide Metabolic Pathway in Moss." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/4853.
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N-Acylethanolamines (NAEs) including anandamide (NAE 20:4) are fatty acid ethanolamides generated by the hydrolysis of N-acylphoshotidylethanolamine (NAPE) by phospholipase D (PLD) and degraded by fatty acid amide hydrolase (FAAH). In mammals, ligands such as NAE 20:4 act through cannabinoid receptors and regulate several physiological processes like neuroprotection, pain perception, mental depression, and appetite suppression. In plants, NAE with chain length C12 to C18 are common and affect physiological processes such as cytoskeletal organization, endomembrane trafficking, cell wall and cell shape formation, seedling growth and response to stress. However, our recent identification of NAE 20:4 in moss, Physcomitrella patens prompted us to elucidate its metabolic pathway and physiological implications. We hypothesize that unique NAE metabolites such as anandamide in moss might play a role in rendering moss its ability to tolerate temperature, dehydration, salt and osmotic stress. To address the above hypothesis, three main objectives are being pursued using P patens. 1)Biochemical and molecular characterization of NAE metabolic pathway, 2) Generation and phenotypic characterization of NAE metabolite mutants, and 3) Elucidation of the physiological role of NAEs in abscisic acid-mediated dehydration tolerance. A NAPE-PLD, known to synthesize NAE 20:4 has been identified in mammals and FAAH in several eukaryotes, including plants. Here, identification and cloning of putative NAPE-PLD and FAAH genes that are likely involved in NAE synthesis and degradation, respectively, in P patens is discussed. Our long-term objective is to understand lipid-mediated stress responses in plants.
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Diouf, Cheikh. "Caractérisation électrique des transistors d’architecture innovante pour les longueurs de grilles décananométriques." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENT082/document.
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La taille du transistor MOS ne cesse de diminuer pour des questions de performance et de rentabilité de fabrication. Les procédés de fabrication évoluent, l'architecture se complexifie et les méthodologies d'extraction de paramètres électriques doivent être adaptées. C'est ainsi que dans un premier temps, les effets d'un recuit haute pression sous atmosphère hydrogène (HPH2) ou deutérium (HPD2) sur le transistor MOS sont étudiés en détail dans cette thèse. La comparaison des performances apportées en termes de transport électronique et de dégradations engendrées en fiabilité a permis de montrer que le HPD2 présente un meilleur compromis. Une étude des effets d'un canal silicium-germanium (SiGe) sur les performances des transistors MOS est ensuite réalisée. L'incorporation du SiGe a permis d'atténuer l'impact négatif sur les performances des charges contenues dans l'empilement de grille. La présence de ces charges est d'ailleurs confirmée par l'analyse des effets néfastes d'un oxyde de grille à haute permittivité, utilisé entre autre pour faciliter la miniaturisation. Dans un deuxième temps, la « fonction Y » a été étendue en régime de saturation afin d'extraire la vitesse de saturation qui est un indicateur de performance obtenu dans les mêmes conditions que le courant ION. En outre, la problématique liée à l'extraction de la charge d'inversion sur des transistors courts et à forte tension de drain VD a été résolue grâce à des mesures à hautes fréquences réalisées sur une structure deux ports. Ceci a rendu possible l'obtention de la mobilité effective, de la vitesse moyenne et de la vitesse limitante sur des transistors déca-nanométriquesThe MOS gate length is continuously downscaling because of the need of higher performance and cost-effectiveness. In addition to the fabrication process, the device architecture is being more and more complex and parameters extraction need to be adapted. First in this thesis, the effects of high pressure final anneal with hydrogen (HPH2) or deuterium (HPD2) on MOSFET properties is investigated. The transport performances and reliability degradation comparison allow to consider HPD2 as a good compromise. The effect of a silicon-germanium (SiGe) channel is also studied. It is demonstrated that SiGe channel decreases defects located in the high-κ gate stack. The presence of these defects is confirmed by the study of the negative effects of a high-k as a gate oxide. Secondly, the “Y function” method is extended to the saturation regime to reliably extract saturation velocity, obtained in the same conditions as ION current. The problematic due to inversion charge estimation in short devices is solved using high frequency measurements with a two ports structure. Then, effective mobility, average velocity and limiting velocity are obtained in ultra-scaled devices
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Persson, Stefan. "Modeling and characterization of novel MOS devices." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3720.
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Challenges with integrating high-κ gate dielectric,retrograde Si1-xGexchannel and silicided contacts in future CMOStechnologies are investigated experimentally and theoreticallyin this thesis. ρMOSFETs with either Si or strained Si1-xGex surface-channel and different high-κgate dielectric are examined. Si1-xGex ρMOSFETs with an Al2O3/HfAlOx/Al2O3nano-laminate gate dielectric prepared by means ofAtomic Layer Deposition (ALD) exhibit a great-than-30% increasein current drive and peak transconductance compared toreference Si ρMOSFETs with the same gate dielectric. Apoor high-κ/Si interface leading to carrier mobilitydegradation has often been reported in the literature, but thisdoes not seem to be the case for our Si ρMOSFETs whoseeffective mobility coincides with the universal hole mobilitycurve for Si. For the Si1-xGexρMOSFETs, however, a high density ofinterface states giving riseto reduced carrier mobility isobserved. A method to extract the correct mobility in thepresence of high-density traps is presented. Coulomb scatteringfrom the charged traps or trapped charges at the interface isfound to play a dominant role in the observed mobilitydegradation in the Si1-xGexρMOSFETs.
Studying contacts with metal silicides constitutes a majorpart of this thesis. With the conventional device fabrication,the Si1-xGexincorporated for channel applications inevitablyextends to the source-drain areas. Measurement and modelingshow that the presence of Ge in the source/drain areaspositively affects the contact resistivity in such a way thatit is decreased by an order of magnitude for the contact of TiWto p-type Si1-xGex/Si when the Ge content is increased from 0 to 30at. %. Modeling and extraction of contact resistivity are firstcarried out for the traditional TiSi2-Si contact but with an emphasis on the influenceof a Nb interlayer for the silicide formation. Atwo-dimensional numerical model is employed to account foreffects due to current crowding. For more advanced contacts toultra-shallow junctions, Ni-based metallization scheme is used.NiSi1-xGex is found to form on selectively grown p-typeSi1-xGexused as low-resistivity source/drain. Since theformed NiSi1-xGex with a specific resistivity of 20 mWcmreplaces a significant fraction of the shallow junction, athree-dimensional numerical model is employed in order to takethe complex interface geometry and morphology into account. Thelowest contact resistivity obtained for our NiSi1-xGex/p-type Si1-xGexcontacts is 5´10-8Ωcm2, which satisfies the requirement for the 45-nmtechnology node in 2010.
When the Si1-xGexchannel is incorporated in a MOSFET, it usuallyforms a retrograde channel with an undoped surface region on amoderately doped substrate. Charge sheet models are used tostudy the effects of a Si retrograde channel on surfacepotential, drain current, intrinsic charges and intrinsiccapacitances. Closed-form solutions are found for an abruptretrograde channel and results implicative for circuitdesigners are obtained. The model can be extended to include aSi1-xGexretrograde channel. Although the analytical modeldeveloped in this thesis is one-dimensional for long-channeltransistors with the retrograde channel profile varying alongthe depth of the transistor, it should also be applicable forshort-channel transistors provided that the short channeleffects are perfectly controlled.
Key Words:MOSFET, SiGe, high-k dielectric, metal gate,mobility, charge sheet model, retrograde channel structure,intrinsic charge, intrinsic capacitance, contactresistivity.
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Olsson, Tina. "Functional characterization of hexokinases in the moss Physcomitrella patens /." Uppsala : Dept. of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200578.pdf.
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Monaghan, Jacqueline. "Characterization of the MOS4-associated complex in plant defense signaling." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23638.
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The plant immune system is governed in part by Resistance (R) proteins that recognize pathogenic microorganisms and initiate enduring defense responses. While the terminal outputs of R protein activation are fairly well understood, information about signaling components involved in plant immunity is scarce. We previously showed that MODIFIER OF SNC1, 4 (MOS4) associates with the transcription factor AtCDC5 and the WD-40 protein PRL1 in vivo, forming the MOS4-Associated Complex (MAC). The MAC is required for plant defense responses, including those activated in the autoimmune mutant snc1, in which the R protein SNC1 is constitutively active. To identify additional MAC proteins, hemagglutinin-tagged MOS4 was purified by affinity chromatography and over 20 associated proteins were subsequently identified by mass spectrometry. In addition to MOS4, AtCDC5, and PRL1, we identified two homologous U-box proteins as well as several nucleic-acid binding proteins and snRNP subunits predicted to be integral components of the spliceosome. This thesis describes the characterization of selected MAC proteins in plant defense as well as EDS17, a gene unrelated to the MAC but that is likewise required for innate immunity in Arabidopsis.
MAC3A and MAC3B encode highly similar E3 ubiquitin ligases with homology to the yeast and human protein Prp19. Through the analysis of loss-of-function mutants, we found that these loci are genetically redundant and are required for innate immunity in plants. MAC5A and MAC5B encode highly homologous putative RNA-binding proteins similar to the human protein RBM22. Analysis of these loci by reverse genetics revealed that they are partially redundant in a dosage-dependent manner and that both genes are essential for viability in Arabidopsis. Importantly, the loss of either MAC3A/3B or MAC5A suppresses snc1-associated autoimmune responses, indicating that these loci function in the snc1 pathway similar to MOS4. Even though the MAC is closely associated with the spliceosome, we could not detect obvious splicing defects in MAC mutants, indicating that this protein complex is probably not required for general splicing in plants. Together, our data suggest that the MAC likely functions as a transcriptional regulator to fine-tune plant immune responses.
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Pfäffli, Paul. "Characterization of degradation and failure phenomena in MOS devices /." Zürich, 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13274.
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Cai, Yu. "Molecular Characterization of the mop2, a Gene Required for Epigenetic Silencing." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/195361.
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The mop2 gene is required for epigenetic silencing; it was originally defined as a mutation, Mop2-1, which when dominant prevented paramutation at b1. Paramutation is an allele communication that causes a mitotically and meiotically heritable change in gene expression. Mop2-1 was subsequently shown to be involved in maintaining the silenced paramutant state and to prevent dsRNA-mediated transcriptional gene silencing (activities revealed only when the mutation is homozygous). Understanding the product encoded by mop2 will help dissect the underlying mechanisms involved in paramutation and dsRNA-mediated transcriptional silencing. This dissertation describes map-based cloning and candidate gene approaches directed toward the eventual goal of identification of mop2.Initial mapping of mop2 placed it within a region delineated by the markers umc1823 and eks1. On the maize physical map this region contains 21 BAC (Bacteria Artificial Chromosome) clones, representing 2.9 Mb. Skim sequencing identified additional markers for mapping and revealed the gene content. Extensive candidate gene examinations, including gene sequencing, expression profiling with microarrays and RT-PCR, and complementation tests with mutant alleles did not identify any of the four chromatin and RNAi-related genes as mop2.The new markers developed from the skim sequence enabled further mapping and molecular genotyping, which revealed that the Mop2-1 mutation was unstable. Approxi¬mately 10% of phenotypic heterozygous plants were actually genotypic homozygous. Further mapping using only Mop2-1 homozygous plants reduced the mop2 interval to a region of nine BACs, containing 57 genes.The mop2 region is highly syntenic to a rice region of 1.25 Mb on chromosome 4. The gene alignment and repetitive sequence analyses between the syntenic regions in these two species revealed both syntenic and non-syntenic blocks of sequences. Analyses suggested several potential mechanisms for the collinearity breakage, including, but not limited to, tandem duplications of genes in one species but not the other and the presence of gene fragments in maize, but not in rice.The research described herein provides the basis for continued efforts to clone mop2. Fine-structure mapping with new markers and a larger population, as well as candidate gene sequencing in the Mop2-1 BAC library, should be pursued to clone mop2.
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Krogan, Naden Theodore. "Isolation and characterization of MADS-box genes from the moss, Physcomitrella patens." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0019/MQ54717.pdf.
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Gautam, Deepshila, and Aruna Kilaru. "Characterization of changes in lipid profile during development of the moss Physcomitrium patens." Digital Commons @ East Tennessee State University, 2021. https://dc.etsu.edu/asrf/2021/presentations/3.
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Lipids are the main constituents of the cell membrane and maintain its fluidity. Plants undergo various changes in lipids under environmental stresses and alter the membrane fluidity and permeability. Membrane lipids mostly contain a polar or neutral head group and fatty acid tails that vary in length and degree of unsaturation. The composition of membrane affects its physicochemical properties and ability to tolerate stress. The moss Physcomitrium patens is an early land plant with unique ability to tolerate stressors like cold and dehydration. During its life cycle, for the most part, mosses remain as gametophytes, multiplying asexually. The period from germination of spores into filamentous protonema, which give rise to gametophyte is transient. They enter reproductive sporophytes stage only under cold temperatures. Because of the diverse roles of these developmental stages and the time span they are exposed to the environment, we hypothesized that these stages share distinct lipid content and composition. To this extent, using LC-MS/MS methods we carried out lipidomic analyses of five developmental stages of the moss. We identified and quantified the major and minor lipid classes (types) and their acyl composition of protonema, early, mid and late gametophyte and sporophyte tissues. Galactolipids, which typically occur in the plastid were predominant in green tissues and thus most abundant in the vegetative tissues but not in sporophytes. Throughout the life cycle, among the phospholipids, phosphatidylcholine was the abundant lipid, a feature that is typical of plant membranes. Sporophyte tissues, however, were distinct from gametophyte and protonema and also other vascular plants with high amounts of phosphatidic acid (PA). In plants, PA typically accumulates in response to stress; it is likely that the low temperature cue necessary for sporophyte formation is associated with spike in PA and needs further investigation. In comparing the acyl composition of the various lipid classes, we identified that in addition to 34C and 36C lipids, moss lipids also contain 38C and 40C, which are not represented in vascular plants. We predict that the occurrence of long-chain, highly unsaturated lipids might contribute to the dynamic nature of the membrane and stability under stress. This study serves as a primary resource to further investigate the role of specific lipids and acyl groups in maintaining membrane properties. Overall, it aids to our understanding of the evolution of stress tolerance in early land plants that coped through harsh environmental conditions during their transition from water to land.
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Sridhara, Karthik Ruzllyo Jerzy. "Characterization of MOS capacitor gate oxide embedded with silicon quantum dots." [University Park, Pa.] : Pennsylvania State University, 2009. http://etda.libraries.psu.edu/theses/approved/PSUonlyIndex/ETD-4079/index.html.
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Kerber, Andreas. "Methodology for electrical characterization of MOS devices with alternative gate dielectrics." Phd thesis, [S.l. : s.n.], 2004. http://elib.tu-darmstadt.de/diss/000404.
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Zurauskaite, Laura. "Fabrication and electrical characterization of Ge/GeOx/Al2O3/HfO2 MOS capacitors." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-204909.
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Continuous scaling of complementary metal oxide semiconductor (CMOS) devices has led to constant increase in device performance. However, as scaling becomes more difficult with every technological node, alternative channel materials that could replace silicon (Si) are being investigated [1]. Germanium (Ge) is an attractive material because of its four times higher hole mobility and twice higher electron mobility compared to silicon [2]. Nevertheless, Ge suffers from surface passivation issues that need further investigation. A modification of oxidation through a barrier layer method proposed by Takagi group[3] has been employed for the fabrication of MOS capacitors. Ozone oxidation has been performed in-situ in atomic layer deposition (ALD) chamber using Al2O3 layer as a barrier. Combinations of barrier thickness and ozone generator power have been investigated together with the influence of the oxidation time. Electrical characterization has revealed that the Ge/oxide interface is improved while employing high ozone generator power oxidation through a thin (~0.47 nm) barrier as well as prolonged oxidation times up to 15 min. Interface state density has been suppressed to lowto mid 1012 cm-2eV-1.Kontinuerlig skalning av komplementär MOS teknologi (CMOS), har lett till konstant förbättrad prestanda hos integrerade CMOS-kretsar. Fortsatt nerskalning möter dock större hinder för varje teknologinod och forskare undersöker alternativa material till kisel (Si) [1]. Germanium (Ge) är ett attraktivt material eftersom hålmobiliteten är fyra gånger och elektron mobilitet två gånger högre än hos kisel [2]. En utmaning med att bygga CMOOS pp Ge är att det är svårt att passivera Ge. I denna avhandling undersöks en modifikation på metoden att oxidera genom ett barriärlager som föreslagits av gruppen som leds av Takagi [3]. Ozon oxidering har utförts in-situ i en atmoic layer deposition (ALD) kammare där Al2O3 användes som ett barriär lager och MOS kondensatorer har tillverkats och karakteriserats. Kombinationer av barriär tjocklek och ozongeneratoreffekt har undersökts tillsammans med influensen av oxideringstid. Karakterisering av elektriska egenskaper har visat att gränsytan mellan germanium och oxid förbättras då en hög ozongeneratoreffekt används för att oxidera genom en tunn (~0.47 nm) barriär och genom att använda en förlängd oxideringstid upp till 15 min. Defektdensiteten (Dit) vid gränssnittet till Ge sjönk med oxideringstiden och som lägst uppmättes till ~3·1012 cm-2eV-1.
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Gannon, Patrick. "Characterization and cloning of defence-related suppressors of mos4-1 snc1 in Arabidopsis thaliana." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36788.
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In response to pathogen infection, plants typically use RESISTANCE (R) proteins to recognize and induce a strong defence response. SNC1 belongs to a class of R-proteins, and the gain of function snc1 mutant has constitutively active immune responses. MOS4 has been identified through a snc1 suppressor screen. MOS4 interacts in a complex called the mos4-associated complex (MAC) which is homologous to splicing-related complexes in yeast and humans. However, no splicing defects have been observed in any MAC single mutants. Two MAC proteins, AtCDC5 (a transcription factor) and MAC3A/3B (an E3 ubiquitin ligase) could be responsible for defence signalling downstream of the MAC. Since mos4-1 has the same defence phenotype as both atcdc5 and mac3a/3b, mutations to any of these genes probably has the same effect on perturbing the MAC. We performed a mos4-1 snc1 suppressor screen to identify signalling components downstream of the MAC.
The suppressor screen identified 31 dwarf mutants that all had either high PR2 defence gene expression or resistance to a virulent pathogen, H.a. Noco2, suggesting that the mutations affect defence signalling. Three mutants, 60B-1, 83-2 and 39-1, were characterized in greater detail and each of their respective mutations were mapped. 60B-1 carries a mutation to a known negative regulator of defence signalling, BON1. 83-2 carries a further gain of function mutation to snc1, however, unlike snc1 which causes snc1 protein accumulation, snc1 protein accumulation in 83-2 does not appear to be affected, suggesting that the protein is converted into a more active form. The molecular lesion in 39-1 was mapped near the southern telomere of chromosome 1, its exact location awaits discovery.
We have shown that a mos4 snc1 suppressor screen can successfully identify both recessive negative regulators of defence and dominant positive regulators of defence.
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Zheng, Shufang. "Characterization of enzymes involved in the metabolism of dihydrotestosterone, the most potent natural androgen." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27693/27693.pdf.
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Zheng, Shu-Fang. "Characterization of enzymes involved in the metabolism of dihydrotestosterone, the most potent natural androgen." Master's thesis, Université Laval, 2010. http://hdl.handle.net/20.500.11794/21569.
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Chez l'humain, la formation des hormones stéroïdiennes dans les tissus périphériques via le précurseur déhydroépiandrostérone (DHEA) circulant joue un rôle majeur dans le maintien du fonctionnement adéquat des tissus androgéno- et estrogéno-sensibles. Comme les primates ont le pouvoir de sécréter une grande quantité de DHEA via les glandes surrénales, le singe représente ainsi un meilleur modèle animal pour étudier la stéroïdogénèse que le rat ou la souris. Chez ces derniers, l'enzyme 17α-hydroxylase, 17,20-lyase (CYP17) est absente dans les glandes surrénales, lesquelles sont donc incapables de produire et de sécréter la DHEA et la 4-androstène-3,17-dione (4-dione) dans la circulation, comme le font humain et les primates. Dans le présent projet, nous étudions deux enzymes chez le singe cynomolgus (Macaca fascicularis) qui possèdent le potentiel de métaboliser les androgènes, mais les preuves de leur implication réelle sont encore manquantes. La première est la rétinol déshydrogénase de type 12 (RDH12) qui transforme le rétinal en rétinol, les résultats préliminaires obtenus dans notre laboratoire suggèrent qu'elle possède la capacité de convertir la dihydrotestostérone (DHT) en 5α-androstane-3p, 17β-diol (3β-diol). La deuxième enzyme est la 17β-hydroxysteroide dehydrogenase (17β-HSD) type 11, qui possède la capacité de catalyser la transformation du 5α-androstane-3α, 17β-diol (3α-diol) en androstérone (ADT). Pour déterminer les activités catalysées par la RDH12, nous avons préparé des transfectants stables qui expriment l'enzyme en utilisant les cellules transformées de rein embryonnaire d'humain (HEK-293). Nous avons trouvé que Macaca fascicularis RDH12 (mfRDH12) catalyse efficacement et sélectivement la transformation de 5α-androstane-3,17-dione (5α-dione) en epiandrostérone (Epi-ADT) et DHT en 3β-diol, respectivement. L'enzyme est exprimée spécifiquement dans la peau, la glande mammaire et le cerveau. Le niveau d'expression le plus élevé est dans la peau où elle est exprimée spécifiquement dans la glande sébacée. En utilisant l'androgène synthétique R1881 pour déterminer s'il est capable de stimuler l'expression de la RDH12 comme celle de la rétinol déshydrogénase de type 11 (RDH11), une enzyme paralogue de la RDH12, nous avons trouvé que ce produit ne stimule pas l'expression de la RDH12, par contre, il est un inhibiteur puissant de l'activité 3β-hydroxystéroïde déshydrogénase. Pour déterminer le rôle potentiel de la 17β-HSD type 11 dans le métabolisme des androgènes, nous avons quantifié le niveau d'expression de l'enzyme, déterminé la localisation de l'enzyme dans plusieurs tissus en utilisant le PCR en temps réel et l'hybridation in situ, et examiné s'il y a association avec les tissus androgéno-sensibles.
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Schrader, Michael John. "Considerations for Electrical Characterization of MOS Capacitors that Arise Due to Processing." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010710-152356.
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The goal of this research was to determine the effects thatthe actual physical structure of an overlapped metal-oxide-semiconducter (MOS) capacitor and an etch bias have on the extraction of the gate-oxide thickness. Included in these concerns were the overlap of the field oxide by the gate electrode, the angle of the active-area sidewall, and the increase in size of the active area due to an etch bias. In addition, the growth of a contaminant layer, or ad-layer,on oxides that do not have a permanent gate-electrode was addressed. This ad-layer forms immediately after a wafer is exposed to the lab ambient and causes a significant increase (i.e., ~ 10%) in the apparent thickness of the oxide.The refinement of the total capacitance to the active-area capacitance uses measured data from Hg-gated capacitors on p-type Si wafers and Al / Poly-Si gated capacitors on both p- and n-type Si wafers. The effects of a non-vertical sidewall and an etch bias are addressed theoretically through the use of the classic treatment of capacitance. The capacitance-voltage characteristics from the MOS capacitors were used to extract the oxide thickness (tox).The extracted thickness was determined from a model-based methodology (i.e., the slope method) and a model-based analysis (i.e., NCSU's CVC model). It is shown that the effect of a non-vertical sidewall and an etch bias are negligible. The effect of the gate electrode overlap, while small, should be removed. It is also shown that a model-based analysis of the active-area capacitance characteristics results in a consistent oxide thickness over the range of capacitor areas that were available.The removal and re-growth of the ad-layer were investigated using current-voltage and capacitance-voltage characteristics from blanket oxides on both p- and n-type silicon wafers. The changes in these characteristics were quantified as the ad-layer grows over time. The C-V characteristics were analyzed using NCSU's CVC program in order to extract values for oxide thickness, flatband voltage, and interface trap densities. The ad-layer causes considerable inaccuracies in the model extraction of oxide thickness as well as the flatband voltage and interface trap density. Electrical and optical results on the p-type wafer both show that the ad-layer increases the apparent oxide thickness by ~ 0.25 nm and the electrical results show that the ad-layer shifts the flatband voltage by as much as 100 mV.
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Gabrys, Ann M. "Interface state characterization techniques for MOS capacitors incorporating ultra-thin dielectric films /." Diss., ON-CAMPUS Access For University of Minnesota, Twin Cities Click on "Connect to Digital Dissertations", 2001. http://www.lib.umn.edu/articles/proquest.phtml.
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Thesis (M.S.)--University of Minnesota, 2001."Accompanying CD-ROM contains Excel spreadsheets and Mathematica notebooks that contain data and templates" for further investigation.--P. 68. Includes bibliographical references (leaves 70-71). Also available on the World Wide Web as a PDF file.
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Oliveira, Alessandro Ricardo de. "Estudo da viabilidade de fabricação de dispositivos semicondutores baseados em filmes de carbeto de silício crescidos por PECVD." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-08122006-142624/.
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Neste trabalho é estudada a viabilidade de produção de dispositivos eletrônicos baseados em filmes semicondutores de carbeto de silício estequiométrico (a-Si0,5C0,5:H) obtidos por deposição química por vapor assistida por plasma, PECVD. A proposta do projeto envolve a realização de uma série de trabalhos que permitam avaliar as potencialidades do a-SiC:H para a fabricação de dispositivos semicondutores simples. Deste modo, desenvolvemos as principais etapas para a construção de dispositivos, as quais envolveram a dopagem elétrica por diferentes técnicas com a utilização de diferentes elementos dopantes, a corrosão seletiva por plasma e a obtenção um dielétrico apropriado e compatível com a tecnologia do SiC, bem como o desenvolvimento de processos de cristalização, que podem se mostrar fundamentais para melhorar as propriedades dos filmes de a-SiC:H. Com tais processos aprimorados, fabricamos estruturas MOSiC (metal-óxidocarbeto de silício) a partir do SiC cristalizado, utilizando como dielétrico de porta o SiO2 crescido por oxidação térmica (seca e úmida) dos próprios filmes de carbeto de silício cristalizados. Essas estruturas apresentaram o comportamento típico de um capacitor MOS, com regiões de acumulação, depleção e inversão bem definidas em todos os casos. Também fabricamos heterojunções de filmes de SiC tipo-p (como depositado e tratado termicamente) sobre substratos de Si tipo-n, os quais mostraram boas caracterísitcas retificadoras para as heteroestruturas formadas pelo a-SiC:H como-depositado e tratado termicamente a 550ºC. Além do mais, também projetamos, fabricamos, modelamos e caracterizamos transistores de filme fino de a-SiC:H. De acordo com as caracterizações elétricas observamos que podemos controlar a condutividade do canal, embora os dispositivos ainda precisem ser aprimorados para se obter melhores níveis de corrente. Vemos, portanto que, embora ainda tenham que ser aperfeiçoados, foram construídos com sucesso dispositivos eletrônicos semicondutores baseados em filmes de a-Si0,5C0,5:H obtidos por PECVD.In this work we studied the viability to build devices based on stoichiometric amorphous silicon carbide semiconductor films (a-Si0.5C0.5:H), obtained by plasma enhanced chemical vapor deposition technique. The project proposal involves the realization of a series of studies that evaluate the potentialities of the a-SiC:H for the fabrication of simple semiconductor devices. In this way, we developed the main steps for the devices\' fabrication, which involved electric doping, by different doping techniques using different doping sources, selective plasma etching and the obtention of an appropriate and compatible dielectric for SiC technology. Besides, we performed crystallization processes that were essential to improve the properties of the amorphous films. By establishing the processes steps, we manufactured MOSiC (metal-oxidesilicon carbide) structures starting from crystallized SiC and using SiO2 as the gate dielectric, which was obtained by thermal oxidation (wet and dry) of the crystallized silicon carbide films. All the structures presented a typical MOS capacitor behavior, with accumulation, depletion and inversion regions well-defined in all the cases. We also fabricated heterojunctions formed by p-type SiC films (as-deposited and annealed) on n-type silicon substrates that showed good rectifying characteristics for as-deposited and annealed at 550ºC a-SiC:H films. Moreover, we designed, manufactured, modeled and characterized a-SiC:H thin film transistors. The electric characterization demonstrated that it is possible to control the channel conductivity; however, the devices still need to be improved to obtain better current levels. Although some improvement still need to be made, we built successfully electronic semiconductor devices based on a-Si0.5C0.5:H films obtained at low temperatures by PECVD technique.
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Bañados, Torres Eduardo [Verfasser], and Fabian [Akademischer Betreuer] Walter. "The discovery and characterization of the most distant quasars / Eduardo Banados Torres ; Betreuer: Fabian Walter." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180499980/34.
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Peng, Congyue. "Characterization of a membrane protein encoding cDNA (TrDr3) from the desiccation-tolerant moss Tortula ruralis /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1597629781&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Kinser, Brent, and Aruna Kilaru. "Cloning and Characterization of a Putative Fatty Acid Amide Hydrolase Gene in Moss, Physcomitrella Patens." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/4855.
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Negre, Laurent. "Caractérisation et modélisation de la fiabilité des transistors MOS en Radio Fréquence." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENT126/document.
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Les produits issus des technologies Silicium tendent à exploiter au maximum les performancesdes transistors MOS tout en les soumettant à des profils de mission très agressifs du point de vuede la fiabilité. Les concepteurs sont ainsi à la recherche du meilleur compromis entre performanceet fiabilité.Historiquement, l’étude de la fiabilité du transistor MOS et le développement des modèlessous jacents ont été menés sur la base de contrainte de vieillissement statique. Avec le développementdes produits à hautes performances dans le domaine de la radiofréquence (RF), laquestion de la fiabilité pour ce type d’application se pose. Ainsi, une extension des modèles defiabilité doit être réalisée afin de quantifier le vieillissement des paramètres clés RF soumis àdes contraintes statiques mais également RF. C’est cette extension de la fiabilité des transistorsMOS dans le domaine RF qui constitue le sujet de ce travail de thèse.Dans ce manuscrit, le fonctionnement du transistor MOS est décrit et sa fiabilité est introduite.Les différents mécanismes de dégradation sont étudiés et leurs modèles associés décrits.Sont ensuite présentés un banc de mesure et une méthodologie nécessaire à l’étude du vieillissementdes transistors dans le domaine RF, ainsi qu’à l’extension des modèles de fiabilité audomaine RFProducts using nowadays silicon technology are generally targeting aggressive specificationsand push the developers to determine the best compromise between performance and reliability.Main front-end degradation mechanisms are historically studied and modeled under static stressconditions and focus on the static MOS transistor parameters.With the development of product targeting high performances in the radio frequency (RF)domain, the reliability is becoming a first order concern. Thus an extension of the actual staticreliability models must be done to quantify the aging of key RF parameters under static andRF stress. In this context, this work focuses on the extension of the MOS transistor reliabilityregarding the study of RF parameters and also the application of RF stress.After describing the MOS transistor properties, the reliability aspect is introduced and theemphasis is put on the different degradation mechanisms and their associated models. Thisallows the development of an experimental setup and the required methodology to investigatethe device aging in the RF domain and to extend actual static models
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Chen, Zuhui. "Investigation of theoretical limitations of recombination DCIV methodology for characterization of MOS transistors." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010826.
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Sell, Bernhard. "Interface characterization of metal-gate MOS-structures and the application to DRAM-capacitors." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=975788124.
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Wutikuer, Otkur. "Fabrication and Characterization of 4H-SiC MOS Capacitors with Different Dielectric Layer Treatments." Thesis, Linköpings universitet, Halvledarmaterial, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-144984.
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4H-SiC based Metal-Oxide Semiconductor(MOS) capacitors are promising key components for next generation power devices. For high frequency power applications, however, there is a major drawback of this type of devices, i.e. they have low inversion channel mobility that consequently affects the switching operation in MOS Field-Effect Transistors (MOSFETs). Carbon clusters or excess carbon atoms in the interface between the dielectric layer and SiC is commonly considered to be the carrier trapping and scattering centers that lower the carrier channel mobility. Based on the previous work in the research group, a new fabrication process for forming the dielectric layer with a lower density of the trap states is investigated. The process consists of standard semiconductor cleaning, pre-treatments, pre-oxidation, plasma enhanced chemical vapor deposition (PECVD) and post oxidation annealing. I-V measurements of the dielectric strength showed that the resulting layers can sustain proper working condition under an electric field of at least 5MV/cm. C-V characteristics measurements provided the evidence that the proposed method can effectively reduce the interfacial states, which are main culprit for a large flat band voltage shift of C-V characteristics, in particular under annealing at 900°C in nitrogen atmosphere.
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Bezza, Anas. "Caractérisation et modélisation du phénomène de claquage dans les oxydes de grille à forte permittivité, en vue d’améliorer la durée de vie des circuits issus des technologies 28nm et au-delà." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT097.
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.Aujourd’hui, la course à la miniaturisation a engendré de nouveaux défis dans l’industrie microélectronique. En plus de la forte concurrence que subissent les fabricants de composants, de nouvelles contraintes liées à la fiabilité des dispositifs se sont imposées. En effet, le passage d’une technologie « tout silicium » relativement simple à une technologie high-k/grille métal plus complexe, a entrainé une forte réduction des marges de fiabilité des oxydes de grille. A ce titre, Il est devenu nécessaire d’investiguer de nouvelles approches pouvant offrir davantage de gain en durée de vie pour les transistors MOS. C’est dans ce contexte que s’inscrit ce travail de thèse. Dans un premier temps, une présentation des différentes méthodes de caractérisations adaptées à l’étude du vieillissement des dispositifs high-k à grille métallique est faite. Dans ce cadre, des techniques de mesures rapides (type FAST BTI) sont mises en place et adaptée à l’étude du claquage d’oxyde. Ensuite, afin de démontrer que les durées de vie estimées aujourd’hui sont pessimistes, une étude de fiabilité portant sur la compréhension et la modélisation du mécanisme de TDDB (Time Dependent Dielectric Breakdown) sur les technologies avancées à base d’oxyde IL/high-k est présentée. Enfin, le manuscrit se focalise sur un certain nombre d’axes de travail qui pourraient permettre de dégager une marge significative sur la durée de vie TDDB.Today, in the race for miniaturization, the microelectronics industry faces new challenges. In addition to the strong competition of other component manufacturers, new constraints related to the reliability of devices have emerged. Indeed, the transition from the "all silicon" technology relatively simple to the high-k/metal gate technology has generated a reduction in reliability margins of gate oxides. As such, it becomes necessary to investigate new approaches that can provide more gain in lifetime for the MOS transistors. In this respect, this work gives firstly an overview of different methods of characterization used for the study of aging high-k metal gate devices. In this context, the need to develop and implement new fast techniques essential to the study of the oxide breakdown is exposed. Afterwards, in order to show that the estimated lifetimes today are pessimistic, we presented a reliability study based on understanding and modeling the mechanism of TDDB (Time Dependent Dielectric Breakdown) on advanced high-k/metal gate stacks based technology. Finally, the manuscript focuses on a number of investigation areas that could provide a significant margin for the TDDB lifetime
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Hossain, Md Tashfin Zayed. "Electrical characteristics of gallium nitride and silicon based metal-oxide-semiconductor (MOS) capacitors." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/16942.
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Doctor of PhilosophyDepartment of Chemical Engineering
James H. Edgar
The integration of high-κ dielectrics with silicon and III-V semiconductors is important due to the need for high speed and high power electronic devices. The purpose of this research was to find the best conditions for fabricating high-κ dielectrics (oxides) on GaN or Si. In particular high-κ oxides can sustain the high breakdown electric field of GaN and utilize the excellent properties of GaN. This research developed an understanding of how process conditions impact the properties of high-κ dielectric on Si and GaN. Thermal and plasma-assisted atomic layer deposition (ALD) was employed to deposit TiO₂ on Si and Al₂O₃ on polar (c-plane) GaN at optimized temperatures of 200°C and 280°C respectively. The semiconductor surface treatment before ALD and the deposition temperature have a strong impact on the dielectric’s electrical properties, surface morphology, stoichiometry, and impurity concentration. Of several etches considered, cleaning the GaN with a piranha etch produced Al₂O₃/GaN MOS capacitors with the best electrical characteristics. The benefits of growing a native oxide of GaN by dry thermal oxidation before depositing the high-κ dielectric was also investigated; oxidizing at 850°C for 30 minutes resulted in the best dielectric-semiconductor interface quality. Interest in nonpolar (m-plane) GaN (due to its lack of strong polarization field) motivated an investigation into the temperature behavior of Al₂O₃/m-plane GaN MOS capacitors. Nonpolar GaN MOS capacitors exhibited a stable flatband voltage across the measured temperature range and demonstrated temperature-stable operation.
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Marzaki, Abderrezak. "Développement de technique de procédé de fabrication innovante et de nouvelle architecture de transistor MOS." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4768.
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La miniaturisation des composants et l’amélioration des performances des circuits intégrés (ICs) sont dues aux progrès liés au procédé de fabrication. Malgré le nombre de technologie existante, la technologie CMOS est la plus utilisée. Dans le cadre du développement de la technologie CMOS 90nm à double niveau de poly, des recherches sur l’introduction de techniques innovantes de procédé de fabrication et d’une nouvelle architecture de transistor MOS à tension de seuil ajustable ont été menées dans le but d’améliorer les performances des ICs. Une première étude sur l’implémentation des effets de pointe dans les ICs, en particulier pour les mémoires non volatiles est entreprise. Un nouveau procédé de fabrication permettant d’obtenir des pointes dans un matériau est proposé. Il est démontré le gain en courant tunnel obtenu sur une structure pointue par rapport à une structure plane. Une seconde étude est orientée sur le développement d’une nouvelle technique de « patterning ». Les techniques de « patterning » permettent de réduire les dimensions de la photolithographie sans utiliser de masque ayant des dimensions agressives. Les avantages de cette nouvelle technique aux niveaux de sa mise en œuvre et de la suppression des problèmes d’alignement sont présentés. Une dernière étude sur le développement d’un transistor à tension de seuil ajustable est développée. Il est démontré l’avantage de ce composant par rapport aux autres composants à tension de seuil ajustable. La réalisation du modèle et des premières simulations électriques de circuit élémentaire à base de se composant sont présentés. L’amélioration de certaines performances des circuits élémentaire est démontréeThe component miniaturization and the circuit performance improvement are due to the progress related to the manufacturing process. Despite the number of existing technology, the CMOS technology is the most used. In the 90nm CMOS technology development, with a double poly-silicon level, the research on the introduction of innovative manufacturing process techniques and a new architecture of MOS transistor with an adjustable threshold voltage are carried out to improve the integrated circuit performances. A first study, on the peak effect implementation in the integrated circuits, particularly in the non-volatile memories is undertaken. A new process to obtain a peak effect in a material is proposed. It is shown the tunnel current gain obtained on a peak structure compared with a planar structure. A second study is focused on the development of a new patterning technique. The patterning techniques allow to reduce the photolithography dimensions without using an aggressive mask. The advantages of this new technique in terms of its implementation and the suppression of alignment problems are presented. A last study on the development of a MOS transistor with an adjustable threshold voltage is developed. It is shown the advantage of this component relative to the other components with an adjustable threshold voltage. The model implementation and the first electrical simulations of elementary circuits composed with this new component are presented. The performance improvement of some elementary circuits is demonstrated
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Henry, Jean-Baptiste. "Contribution à l'étude expérimentale des résistances d'accès dans les transistors de dimensions deca-nanométrique des technologies CMOS FD-SOI." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT039/document.
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La réduction des dimensions des transistors à effet de champ MOS a depuis quelques années ralenti à cause de l'émergence de facteurs parasites tels que la résistance d'accès. En effet, la miniaturisation du canal s'est accompagnée par une diminution de sa résistance tandis que celle des zones d'accès à la frontière avec le canal est restée constante ou a augmenté. L'objectif de cette thèse a été de mettre en place une méthodologie de caractérisation électrique prenant en compte cette composante parasite longtemps considérée négligeable dans le milieu industriel.Dans un premier chapitre, le fonctionnement de la technologie CMOS et la spécificité de son adaptation FD-SOI sont d'abord présentées. La deuxième moitié du chapitre est quant à elle consacrée à l'état de l'art de la caractérisation électrique et de leur position vis-à-vis de la résistance d'accès.Le second chapitre présente une nouvelle méthode d'extraction des composantes parasites résistives et capacitives à l'aide de transistors de longueurs proches. Les résultats obtenus sont ensuite comparés aux modèles existants. De ces derniers, un nouveau modèle plus physiquement pertinent est proposé en fin de chapitre.Le troisième chapitre expose une nouvelle méthode de caractérisation électrique basée sur la fonction Y qui permet une analyse du comportement d'un transistor sur l'ensemble de son régime de fonctionnement. Cette nouvelle méthode est ensuite combinée à celle développée dans le chapitre 2 pour assembler un protocole expérimentale permettant de corriger et d'analyser l'impact des résistances d'accès sur les courbes de courant et les paramètres électriques.Finalement, le dernier chapitre applique la méthodologie vue dans la chapitre précédent à l'étude du désappariement stochastique des transistors. Les résultats obtenus sont ensuite comparés aux méthodes en vigueur dans les domaines industriel et académique qui présentent chacune leurs avantages et leurs inconvénients. La nouvelle méthode ainsi proposée tente de garder le meilleur de chacune de ces dernièresThe reduction of the dimensions of field effect MOS transistors has slowed down during the last years due to the increasing importance of parasitic factors such as access resistance. As a matter of fact, channel miniaturisation was accompanied by a reduction of its intrinsic resistance while that of the access region at the frontier with the channnel stayed constant or increased. The goal of this thesis was to set a new electrical characterization method to take into account this parasitic component long considered negligible in by industrials.In the first chapter, CMOS technologies working and its FD-SOI adaptation specificities are presented. The second half of the chapter deals with the state of the art of electrical characterization and their hypothesis about access resistance.The second chapter present a new resistive and capacitive parasitic components extraction method using transistors of close channel length. The results are then compared to existing models from which, a new one more physically accurate is proposed.The third chapter expose a new electrical characterization method based on Y function allowing the analyze of transistor behavior on the whole working regime. This new method is then combined with the one developped in the previous chapter to build a new experimental protocol to correct and analyze the impact of access resistances on current curves and parameters.Finally, the last chapter apply this new methodology to the case of stochastic mismatch between transistors. The results are then compared to the methods used by industrials and academics, each of them having their own pros and cons. The new method proposed tries to keep the best of both previous one
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Heseding, Christiane [Verfasser], Ann [Akademischer Betreuer] Ehrenhofer-Murray, and George [Akademischer Betreuer] Iliakis. "Characterization of the MYST histone acetyltransferase Mof2 in Drosophila melanogaster / Christiane Heseding. Gutachter: Ann Ehrenhofer-Murray ; George Iliakis." Duisburg, 2015. http://d-nb.info/1070170550/34.
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Maslougkas, Sotirios. "Gate oxide characterization of 4H-SiC MOS capacitors : A study of the effects of electrical stress on the flat-band voltage of n-type substrate 4H-SiC MOS capacitors." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301848.
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Silicon is the main material used in electronics. The evolution of power electronics and the need for more power efficient semiconductor devices led silicon to its limits. Silicon carbide is a promising material for electronic applications with a wide band-gap, high critical electric field, high thermal conductivity and saturation velocity. Except from its superiority to silicon, silicon carbide comes with a drawback of about two orders of magnitude more interface traps in the SiC/SiO2 interface compared with silicon. A result of this drawback is a flat-band voltage shift when applying a stress to the gate of MOS capacitors and power MOSFETs. In order to study the pure characteristics of the SiC/SiO2 interface, two stress methods, a current pulse stress and gate voltage upsweep, have been applied on 4H-SiC capacitors with nitrided thermal oxides at room temperature and at higher temperatures. The flat-band voltage recovery was examined. The flat-band voltage could be restored at room temperature with a gate voltage downsweep while a restoration is not needed at higher temperatures. The maximum voltage (initial voltage) and the voltage rate of the downsweep were investigated and higher initial voltages and lower voltage rates showed to lead to better VFB restoration. A 200 millisecond long current pulse stress was implemented and it had almost similar effects as the voltage upsweep which lasts 50 seconds.Kisel är det viktigaste materialet som används i elektronik. Utvecklingen av kraftelektronik och behovet av mer energieffektiva halvledarkomponenter ledde kisel till sina gränser. Kiselkarbid är ett lovande material för elektroniska applikationer med ett brett bandgap, högt kritiskt elektriskt fält, hög värmeledningsförmåga och hög mättningshastighet. Förutom dess överlägsenhet gentemot kisel, kommer kiselkarbid med en nackdel med cirka två storleksordningar fler gränssnittsfällor i SiC / SiO2-gränssnittet jämfört med kisel. Ett resultat av denna nackdel är en förskjutning av flatbands-spänningen, VFB, när man applicerar en spänning på gaten till MOS-kondensatorer och kraft- MOSFETar. För att studera de rena egenskaperna hos SiC/SiO2-gränssnittet har två spänningsmetoder, en strömpulsstress och ett uppåtriktat gate-spänningssvep, applicerats på 4H-SiC- kondensatorer med nitriderade termiska oxider vid rumstemperatur och vid högre temperaturer. Återställning av VFB undersöktes. VFB kan återställas vid rumstemperatur med ett nedåtriktat gate-spänningssvep medan en återställning inte behövs vid högre temperaturer. Den maximala spänningen (initialspänningem) och svephastigheten för det nedåtriktade svepet undersöktes och högre initialspänningar och lägre svephastigheter visade sig leda till bättre VFB-återställning. En 200 millisekund lång strömpuls-stress implementerades och den hade nästan samma effekter som ett uppåtriktat spänningssvep
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Soussou, Assawer. "Modeling and characterization of electrical effects of Ge integration in Metal/High-k/SiGe MOS structures." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT018/document.
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L'introduction du SiGe dans les pMOS (Bulk et FDSOI) exige un bon contrôle de la tension de seuil (VT). Ceci nécessite une extraction précise des paramètres électriques ainsi qu'une compréhension des effets électriques du Ge dans de tels dispositifs. Dans cette thèse, nous avons d'abord proposé des méthodes pour une identification précise des paramètres électriques du « gate stack »: VT, la tension de bande plate (VFB) et l'épaisseur équivalente d'oxyde (EOT). Ces méthodes ont été validées avec des simulations Poisson-Schrödinger (PS) et appliquées avec succès aux mesures. Dans un second temps, nous avons étudié les effets électriques du Ge sur les paramètres du « gate stack » des pMOS. La comparaison des caractérisations électriques (C-V) avec les simulations PS a montré un décalage supplémentaire du travail de sortie effectif qui croit avec le Ge. Des caractérisations STEM, EELS et SIMS ont prouvé que ce décalage est due à la présence de dipôles à l'interface SiGe/oxydeMaintaining good threshold voltage (VT) centering is a paramount challenge for CMOS technology. The SiGe introduction in bulk and FDSOI pFETs requires VT control for such devices. To this end, we have to extract accurately electrical parameters and to understand Ge integration effects in SiGe based pFETs. In this thesis, first, we have proposed extraction methods to determine VT, flat band voltage (VFB) and equivalent oxide thickness (EOT) parameters in bulk and FDSOI transistors. The extraction methods have been validated via Poisson-Schrodinger (PS) simulations and successfully applied to measurements. Second, we have highlighted and explained electric effects of Ge on pMOS gate stack parameters. Electrical characterizations compared with PS simulations have evidenced an additional effective work function increase, induced by Ge, related to interfacial dipoles. STEM, EELS and SIMS characterizations have demonstrated that dipoles are located at SiGe/IL interface
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Klein, Adam Sherman. "Design and Characterization of RFIC Voltage Controlled Oscillators in Silicon Germanium HBT and Submicron MOS Technologies." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34435.
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Advances in wireless technology have recently led to the potential for higher data rates and greater functionality. Wireless home and business networks and 3G and 4G cellular phone systems are promising technologies striving for market acceptance, requiring low-cost, low-power, and compact solutions. One approach to meet these demands is system-on-a-chip (SoC) integration, where RF/analog and digital circuitry reside on the same chip, creating a mixed-signal environment. Concurrently, there is tremendous incentive to utilize Si-based technologies to leverage existing fabrication and design infrastructure and the corresponding economies of scale. While the SoC approach is attractive, it presents major challenges for circuit designers, particularly in the design of monolithic voltage controlled oscillators (VCOs). VCOs are important components in the up or downconversion of RF signals in wireless transceivers. VCOs must have very low phase noise and spurious emissions, and be extremely power efficient to meet system requirements. To meet these specifications, VCOs require high-quality factor (Q) tank circuits and reduction of noise from active devices; however, the lack of high-quality monolithic inductors, along with low noise transistors in traditional Si technologies, has been a limiting factor.
This thesis presents the design, characterization, and comparison of three monolithic 3-4 GHz VCOs and an integrated 5-6 GHz VCO with tunable polyphase outputs. Each VCO is designed around a differential -G_{M} core with an LC tank circuit. The circuits exploit two Si-based device technologies: Silicon Germanium (SiGe) Heterojunction Bipolar Transistors (HBTs) for a cross-coupled collectors circuit and Graded-Channel MOS (GC-MOS) transistors for a complementary (CMOS) implementation. The circuits were fabricated using the Motorola 0.4 μm CDR1 SiGe BiCMOS process, which consists of four interconnected metal layers and a thick copper (10 μm) metal bump layer for improved inductive components.
The VCO implementations are targeted to meet the stringent phase noise specifications for the GSM/EGSM 3G cellular standard. The specifications state that the VCO output cannot exceed -162 dBc/Hz sideband noise at 20 MHz offset from the carrier. Simultaneously, oscillators must be designed to address other system level effects, such as feed-through of the local oscillator (LO). LO feed-through directly results in self-mixing in direct conversion receivers, which gives rise to unwanted corrupting DC offsets. Therefore, a system-level strategy is employed to avoid such issues. For example, multiplying the oscillator frequency by two or four times can help avoid self-mixing during downconversion by moving the LO out of the bandwidth of the RF front-end.
Meanwhile, direct conversion or low-IF (intermediate frequency) receiver architectures utilize in-phase and quadrature (I/Q) downconversion signal recovery and image rejection. Any imbalance between the I and Q channels can result in an increase in bit-error-rate (BER) and/or decrease in the image rejection ratio (IRR). To compensate for such an imbalance, an integrated tunable polyphase filter is implemented with a VCO. Control voltages between the differential I and Q channels can be individually controlled to help compensate for I/Q mismatches.
This thesis includes an introduction to design flow and layout strategies for oscillator implementations. A detailed comparison of the advantages and disadvantages of the SiGe HBTs and GC-MOS device in 3-4 GHz VCOs is presented. In addition, an overview of full-wave electromagnetic characterization of differential dual inductors is given. The oscillators are characterized for tuning range, output power, and phase noise. Finally, new measurement techniques for the 5-6 GHz VCO with a tunable polyphase filter are explored. A comparison between the time and frequency approaches is also offered.Master of Science
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Alfaro, robayo Diego. "Mémoires resistives pour applications Storage Class Memory (SCM)." Thesis, Université Grenoble Alpes, 2020. https://tel.archives-ouvertes.fr/tel-03103308.
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Dans les architectures classiques dites de Von-Neumann pour des systèmes d'information, les blocs de mémoire et de traitement sont séparés. Pour le premier, les temps d'accès sont beaucoup plus importants. Afin d'optimiser les performances, une hiérarchie de mémoire a été mise en place. Elle combine des technologies coûteuses, de petite taille, mais très performantes en termes de vitesse; avec d'autres plus larges, à bas coûts per bit, mais plus lentes. Dans une telle hiérarchie, un gap important existe en termes de temps d'accès et capacité de stockage entre les blocs de mémoire les plus bas et ceux de stockage les plus hauts (mémoires FLASH). Des technologies émergentes non-volatiles, appelées textit{Storage Class Memories (SCM)} sont candidates pour remplir tel gap. Entre elles, les mémoires résistives vives, ReRAM, de l'abbreviation anglaise pour textit{Resistive Random Access Memories}; représentent une alternative très intéressante grâce à leur bonne scalabilité, basse consommation, compatibilité avec la Back-End-Of-Line (BEOL), leurs temps d'écriture et lecture rapides, et bonne endurance. Cependant, plusieurs obstacles empêchent leur implémentation à l'échelle industriel, notamment la haute variabilité des états résistifs et la non-linéarité réduite entre eux, ce qui limite l'implémentation des matrices mémoires larges. Ces deux aspects sont étudiés dans ces travaux de thèse. Pour la variabilité, il se trouve que l'endurance, caractéristique fondamentale vis-à-vis des applications SCM, est aussi dispersée. Ce manuscrit présente des caractérisations électriques en endurance au niveau statistique sur des matrices ReRAM de 4Kb. Plusieurs empilements mémoires furent étudiés, ainsi qu'une grande variété des conditions de programmation pour le cyclage. Il a été observé comment la valeur médiane et la déviation standard du claquage des mémoires sont principalement affectées par le RESET. Les résultats expérimentaux ont été utilisés dans la proposition d'un modèle stochastique basé sur la génération de défauts dans la couche résistive. Concernant l'autre grand axe de cette thèse, une co-intégration réussie entre une mémoire $HfO_{2}$ (1R) et un sélecteur (1S) de type textit{Ovonic Threshold Switch (OTS)}, a été demontrée. Les courants de fuite, obtenus grâce à l'addition de l'OTS, sont compatibles avec des matrices entre 100Mb et 1Gb. Pour la première fois, à notre connaissance, des paramètres influant sur les performances des structures 1S1R ont été étudiés au niveau statistique pour des matrices crossbar à haute densité, ainsi permettant la proposition d'optimisations futures et des nouvelles études incluant des nouveaux matériaux et circuits, pour continuer à améliorer les performances des dispositifs 1S1RIn classical von-Neumann architectures, processing and memory blocks are separated. Latency times for the latter are much more slower. To boost performances, memory hierarchy has been introduced to combine small, fast, but expensive technologies with large, slower, and cheaper ones. In such hierarchy, a notorious latency and storage gap can be distinguished between the lowest memory level and the highest storage one (Flash memories). Emerging non-volatile technologies are called to fill such gap through the so-called Storage Class Memories (SCM). Among them, Resistive Random-Access Memories (ReRAM), represent an interesting candidate to improve flash performances due to their good scalability, low-power consumption, Back-End of Line compatibility, fast writing and erasing process, and good endurance. However, several roadblocks hinder their implementation at large industrial scale, notably high variability, and low non-linearity, which avoids large crossbar arrays implementation. This thesis work explores such aspects to increase attractiveness of ReRAM technologies for SCM applications. For the former, endurance variability is addressed at the array level through various measurements over diverse stacks configurations. Results allow to study the impact of programming conditions on failure mechanisms dispersions, leading to the development of a stochastic model based on defects generation inside the resistive layer. As for the non-linearity issue, successful co-integration between best-in-class $HfO_2$ and $GeSeSbN$ Ovonic Threshold Selector (OTS) in 1S1R structures, is demonstrated. Hence, leakage currents compatible with 100Mb-1Gb bank size are obtained. For the first time, to our knowledge, key parameters of OTS+ReRAM systems for high-density crossbar arrays are identified and studied at the statistical level, allowing proposition of further optimizations and opening the way to a whole field of studies which include new materials and circuits to improve 1S1R performances
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Gilstrap, Richard Allen Jr. "A colloidal nanoparticle form of indium tin oxide: system development and characterization." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33995.
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A logical progression from the maturing field of colloidal semiconductor quantum dots to the emerging subclass of impurity-doped colloidal semiconductor nanoparticles is underway. To this end, the present work describes the formation and analysis of a new form of Tin-doped Indium Oxide (ITO). The form is that of a colloidal dispersion comprised of pure-phase, 4-6 nanometer ITO particles possessing an essentially single crystalline character. This system forms a non-agglomerated, optically clear solution in a variety of non-polar solvents and can remain in this state, at room temperature, for months and potentially, years. ITO is the most widely used member of the exotic materials family known as Transparent Conductive Oxides (TCOs) and is the primary enabling material behind a wide variety of opto-electronic device technologies.
Material synthesis was achieved by initiating a series of interrelated nucleophilic substitution reactions that provided sufficient intensity to promote doping efficiencies greater than 90% for a wide range of tin concentrations. The optical clarity of this colloidal system allowed the intrinsic properties of single crystalline ITO particles to be evaluated prior to their use in thin-films or composite structures. Monitoring the temporal progression of n-type degeneracy by its effects on the optical properties of colloidal dispersions shed light on the fundamental issues of particle formation, band filling (Burstein-Moss) dynamics, and the very origin of n-type degeneracy in ITO. Central to these studies was the issue of excess electron character. The two limiting cases of entirely free and entirely confined electron motion were evaluated by application of bulk-like band dispersion analysis and the effective mass approximation, respectively. This provided a means to estimate the number of excess conduction band electrons present within an individual particle boundary. The ability to control and optimize the level of n-type degeneracy within the colloidal ITO nanoparticle form by compositional variation was also demonstrated. A key to the widespread adoption of a new material by industry is an ability to produce multi-gram and perhaps, kilogram quantities with no significant sacrifice in quality. Accordingly, a modified synthesis process was developed to allow for the mass production of high-quality colloidal ITO nanocrystals.
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Shen, Zhiyuan. "Phylogenetic Characterization of the Kinesin Superfamily and Functional Analysis of PpKin14-Vs in Physcomitrella patens." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/1158.
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Chloroplasts are organelles that convert light energy to chemical energy through photosynthesis. The movement of chloroplasts within the cell for the optimization of light absorption is crucial for plant survival. Cellular motor proteins and cytoskeletal tracks can facilitate transport of organelles. As an ancient superfamily of microtubule-dependent motors, kinesins participate in various cellular activities including cytokinesis, vesicle and organelle movements. Based on phylogenetic relationships and functional analysis, the kinesin superfamily has been subdivided into more than 14 families, most of which can be found in plants. With the ever increasing amount of genomic information, it is important and beneficial to systematically characterize and document kinesins within an organism. As a result of my collaborative work with other members of the Vidali lab, a detailed phylogenetic characterization of the 76 kinesins of the kinesin superfamily in the moss Physcomitrella patens is reported here. We found a remarkable conservation of families and subfamily classes with Arabidopsis, which is important for future comparative analyses of functions. Some of the families are composed of fewer members, while other families are greatly expanded in moss. To improve the comparison between species, and to simplify communication between research groups, we proposed a classification of subfamilies based on our phylogenetic analysis. As part of my efforts in studying chloroplasts motility, I investigated the function of two members of Physcomitrella kinesin family 14 class V proteins, Ppkin14-Va and -Vb. These two proteins are orthologs of the Arabidopsis KAC proteins which mediate actin-based chloroplast movement in Arabidopsis thaliana. In contrast, in the Physcomitrella both actin filaments (AFs) and microtubules (MTs) participate in chloroplast movement. Our results show that Ppkin14-Vs are important for maintaining chloroplast dispersion. They also function during chloroplast light avoidance responses via an AF-dependent, rather than MT-dependent mechanism. Although two Ppkin14- Vs do not act as MT-based motors, our phylogenetic study on moss kinesins provides an important source of information to track other potential kinesins that are predicted to move chloroplasts on MTs.
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Sholeh, Mohammad, and 莫哈末. "Preparation and Characterization of Few-layer MoS2 Nanosheets." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/04439932220963451432.
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碩士國立臺灣科技大學
化學工程系
103
Exfoliation of bulk MoS2 via Li intercalation is an attractive route to large-scale preparation of MoS2 few-layers and it can be used to realize their unique properties in practical applications. In generally, solution-based exfoliation of layered materials results in flakes with lateral sizes of one micron or less on average. In this report, we performed the various preparations using a Li-intercalation method at room temperature to prepare MoS2 few-layers with various flake sizes according to dynamic light scattering (DLS) analysis. MoS2 few-layers with particle sizes ranging 85 to 145 nm are reported. We also characterize the few-layer MoS2 nanosheets by various microscopic and spectroscopic techniques.
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Chi-YuangHuang and 黃啟源. "The Optical Characterization of MoS2 using Polarized Raman Spectroscopy." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/50711418047406762887.
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碩士國立成功大學
光電科學與工程學系
102
In the studies of the optical characterization of MoS2 using polarized Raman spectroscopy, I use micro-Raman spectroscopy system and polarized micro-Raman system to analyze few layers MoS2, and determine the number of few layers MoS2 film by the different Raman shift between the E12g vibration mode and A1g vibration mode. After determination of few layers MoS2 film, the location of single layer, bi-layer, and tri-layer can be founded, then I research these layers (1 to 3) by using micro- polarized Raman system. I find that the A1g vibration mode of few layers MoS2 film show a strong polarization dependence, no matter which layer numbers are. After above experimental, I use the thermal evaporator deposition system to deposit Ag films about 7 nm on the MoS2 sample. After the deposition of metal on the sample, the intensity of Raman peak of MoS2 is proved with great improvement. So, if we want to use the Raman spectra to analyze the properties of MoS2, we can deposit the metal particles on the sample to improve the efficiency of the measurement. This thesis is organized as followed: Chapter 1 includes a brief introduction of the research background and the motivation of this experiment .In chapter 2, I introduced the research about Raman spectroscopy and few layer MoS2 film and the research about Surface Enhanced Raman Spectroscopy (SERS). In chapter 3, I describe the preparation of MoS2 and polarized micro-Raman system. In chapter 4, I introduced my experiment about the determination of few layers MoS2 film by Raman spectroscopy and the polarization dependence of MoS2 SERS spectra of few layers MoS2 film. The summary of my work are concluded in chapter 5.
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張文豪. "Characterization of MoS2–graphene and MoS2–TiO2 composite films as counter electrodes in dye-sensitized solar cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/8sf6h3.
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碩士國立彰化師範大學
光電科技研究所
102
The effect of annealing on the optoelectronic and electrical properties of MoS2 films was examined. The MoS2 film was annealed in the ambient nitrogen and vacuum, respectively. The crystallinity can be enhanced while annealing in vacuum. However, annealing in pure nitrogen ambient could make some of nitrogen incorporation into MoS2, resulting in the degraded crystallinity. A link between the electrical property, crystallinity and annealing temperature of the MoS2 film was established. In addition, the MoS2-graphene and MoS2-TiO2 composite films were characterized as the counter electrodes for Pt-free dye-sensitized solar cells (DSSCs). It is shown that the MoS2-graphene (MoS2-TiO2) counter electrode has a noticeable effect on the power conversion efficiency of DSSCs. A direct link between the power conversion efficiency of DSSCs and the transfer resistance of the MoS2-graphene (MoS2-TiO2) counter electrode was established.
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Chen, Bo-Han, and 陳柏翰. "The optical characterization of MoS2 layered crystals with different dopants." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/84191605832567554977.
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碩士國立臺灣科技大學
電子工程系
101
Electrolyte electroreflectance (EER) and photoresponse spectroscopy in the electrolyte were used to study of doping effects of two-dimensional layered semiconductor MoS2 at room temperature. Single crystals MoS2:X with different dopants X (X=Re, Nb, Fe, Co, Ni) were grown by the chemical vapor transport method using Br2 as transport agent. The electrolytes were 0.5 M H2SO4 or 0.05 M NaI/0.002 M I2/0.05 M H2SO4. EER measurements were carried out under low field regime. For Nb and Re doped samples only exciton A and B related features were observed. The excitonic transition energies of feature A and B were determined precisely and the splitting of excitonic transition energies for A and B were estimated to be around 150 meV. For Fe/Co/Ni doped samples, the two dominant features located at higher energy side as compared with those observed in the Nb/Re doped samples, an additional feature located below A excitonic transition feature were detected and the splitting of A and B features were estimated to be ~200 meV. The differences between these two groups of samples can be attributed to the formation of two different polytypes 3R and 2H. These results were ascertained by the X-ray diffraction patterns of the samples. Detailed analyzing photoresponse spectra, the indirect band gap were determined, the excitonic transition energies of A and B features were estimated and the additional features due to different dopants were detected.
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Chiou, Tz-Chen, and 邱子宸. "Fabrication and characterization of monolayer MoS2 nanosheet transistor for VLSI applications." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/f3zq2t.
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CHEN, HUNG-YI, and 陳鴻毅. "Growth of Large-Scale Single-Layered MoS2 Film via MoO3 Vapor Management and Characterization of MoS2 Thin-Film Transistor Arrays." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/mj9838.
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碩士國立中正大學
光機電整合工程研究所
105
In this study, we have successfully grown the large-scale single-layered MoS2 film by using the atmosphere chemical vapor deposition (APCVD) via MoO3 vapor managements. Raman spectroscopy, Photoluminescence and Atomic Force Microscopy confirmed the MoS2 films are single layer. Also, atomic arrangement and composition were investigated by TEM and XPS. Then, we fabricate the flexible thin film transistor (TFT) arrays with large-scale single-layered MoS2 films, electrical measurements showed the MoS2 TFT is n-type semiconductor characteristic with the average mobility of 8.8 cm2V-1s-1 and the on/off ratio is up to 107. Importantly, the performances of MoS2 TFT arrays are very uniform, the average current at drain voltage of 5 V is about 31.11± 11.55 nA. We also probed the performances of MoS2 TFT arrays under strain, we found that the current decreased when the device under compressive strain, while, the current increased under tensile strain. The changes of the current may be attributed to the bandgap variations. It is worth mentioning that when the stress applied to 0.76%, the device current would increase about 150%. Keywords: Single-layered MoS2 film, CVD, Large-scale growth, High uniformity, Thin-film transistor arrays
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Huang, Yu-Heng, and 黃昱恆. "Synthesis and Characterization of MoS2/ TiO2 Nanotubes Photocatalyst for Dye Wastewater Degradation." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/82719455401788813950.
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碩士元智大學
化學工程與材料科學學系
105
Titanium dioxide has attracted considerable attention for many environmental applications because of its outstanding properties and promising applications. However, the main drawback of TiO2 is the wide bandgap (3.2 eV), which limits its light response to the UV region. In order to overcome these limitations, a novel approach to generate disordered TiO2 with extended absorption profile in visible light region and improved photocatalytic efficiency through a hydrogenation process. Therefore, the objectives of this study were to synthesize and investigate the correlation between structures and photocatalytic activity using XRD, FE-SEM, HR-TEM, Raman, FTIR, XPS, UV-Vis, PL, TGA, and XANES. Experimentally, TiO2 nanobelts composites loaded by MoS2 nanoparticles with enhanced visible-light driven photocatalytic activity were successfully synthesized via a simple two-step hydrothermal method. Preparation of highly photo-activated TNs is achievable by hydrogenation at 450 oC and 30 bar in the duration of hydrogenation (6, 12, and 24 h). In addition, the intensity diffraction peaks for TNs decrease after hydrogenation, indicating the oxygen vacancy increase in the structure and results in a slight decrease on crystal sizes. The crystal structures of TiO2 nanobelts are 4 micrometers in length and 50 nm in width. The surface of TiO2 nanobelts modified by MoS2 nanosheets (MTNs) successfully was observed. MoS2 nanosheets with a lateral size of about 50 nm were distributed on the surface of TNs. The results suggest that the prepared MTNs heterostructure are consisted of Ti4+, S2-, and Mo4+. The characteristic Raman peaks of TNs at 142 cm-1, 197 cm-1, 398 cm-1, 515 cm-1, and 640 cm-1 were ascribed to the Eg1, Eg2, B1g1, A1g+B1g2, and Eg3 are different vibration modes of anatase, respectively. The strongest peak at 142 cm-1 was the symmetric stretching modes of O–Ti–O. Moreover, the Raman peak at both 297 cm-1 and 334 cm-1 which were ascribed to the E2g and A1g vibration modes of MoS2, respectively. Functional groups identified by FTIR on the surface of MoS2/TNs were O-H (3441cm-1), Ti-OH (1627 cm-1), and -OH (3431 cm-1). The pure TNs show a significant absorption edge at a wavelength shorter than 400 nm, which can be assigned to the intrinsic bandgap absorption. Furthermore, the calculated bandgap energy for TNs is 3.19 eV. The absorption edge of MTNs20 (20 wt% MoS2) is red-shifted, which can be attributed to the chemical bonding between TiO2 and MoS2. Similarly, the calculated bandgap energy for MTNs20 is 2.89 eV. The intensity of hydrogenated TNs increase compared relatively with unhydrogenated ones under the visible and infrared region. The absorption edges of hydrogenated TNs composited with the molybdenum disulfide composites indicated that it may produce the largest red shift. It was confirmed that the hydrogenation treatment and the load MoS2 could enhanced the photoresponse range and improve the light absorption capacity of TNs in the visible region. The as-prepared hydrogenated MTNs20 composites show the highest photocatalytic efficiency for the photocatalytic decolorization of Rhodamine B (RhB) aqueous solution under visible light irradiation. Highly apparent photocatalytic reaction of H2 MTNs20 is about 5 times than that of pure TiO2 nanobelts. The rate constants followed the order in series are H2 MTNs20 > H2 24 h > H2 12 h > H2 6h > MTNs20 > MTNs40 > TNs > MTNs60.