Academic literature on the topic 'Nanostructure - Graphene'

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Journal articles on the topic "Nanostructure - Graphene"

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Fan, Jiakang. "The realization of a broadband light absorber via the synergistic effect of graphene and silicon nanostructures." Journal of Physics: Conference Series 2285, no. 1 (June 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2285/1/012001.

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Abstract Due to the increasing demand for clean energy, it becomes more and more necessary to find out more efficient ways to generate clean energy. Because of this, the light conversion efficiency of different materials has been largely studied. The purpose of the study is to investigate how the silicon pyramidal nanostructures and graphene layer affect the light-absorbing performance of materials and achieve a broadband light absorber. Simulations of four experimental groups, including both with nanostructure and graphene, with nanostructure and without graphene, without nanostructure and with graphene, both without nanostructure and graphene, are done to obtain and compare the data through the method of finite difference time domain (FDTD). By analyzing the simulation results, it is found that the silicon pyramidal structures can improve the light absorption within the range of visible light. Moreover, the presence of graphene layers can improve the light absorption within the range of near-infrared to infrared light. The number of layers can also have effects on light absorption.
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Avila, Antonio F., Aline M. de Oliveira, Viviane C. Munhoz, and Glaucio C. Pereira. "Graphene-CNTs into Neuron-Synapse Like Configuration a New Class of Hybrid Nanocomposites." Advanced Materials Research 1119 (July 2015): 116–20. http://dx.doi.org/10.4028/www.scientific.net/amr.1119.116.

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This paper describes the experimental procedures for developing and testing of a new class of hybrid nanocomposites, the neuron-synapse configuration ones. Two carbon based nanostructures, multiwall carbon nanotubes and multi-layered graphene, were incorporated to carbon epoxy laminated. The processing technique employed which includes a combination of sonication and high shear mixing allows the formation of a neuron-synapse nanostructure. X-ray diffractometry indicates that multi-layer graphene (MLG) has an average diameter close to 22 nm. TEM observations and raman spectroscopy revealed a thickness of 10 graphene layers, and a hybrid nanostructure where MWNT interpenetrated the MLG nanostructure. The hybrid nanostructure seems to be linked by Van der Walls bonds. This could be the reason for large crack density generated during short-beam bending tests. No significant stiffness changes were observed in both, tensile and bending, tests, while tensile strength were improved by 19% with 1 wt.% addition of graphene the interlaminar shear strength, was increased by 22% with the addition of MWNTs and 2.5% with the graphene (1 wt.%) and MWNT (0.3 wt.%) together.
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Wallace, Steaphan M., Thiyagu Subramani, Wipakorn Jevasuwan, and Naoki Fukata. "Conversion of Amorphous Carbon on Silicon Nanostructures into Similar Shaped Semi-Crystalline Graphene Sheets." Journal of Nanoscience and Nanotechnology 21, no. 9 (September 1, 2021): 4949–54. http://dx.doi.org/10.1166/jnn.2021.19329.

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Graphene sheets displaying partial crystallinity and nanowire structures were formed on a silicon substrate with silicon nanowires by utilizing an amorphous carbon source. The carbon source was deposited onto the silicon nanostructured substrate by breaking down a polymer precursor and was crystallized by a nickel catalyst during relatively low temperature inert gas annealing. The resulting free-standing graphene-based material can remain on the substrate surface after catalyst removal or can be removed as a separate film. The film is flexible, continuous, and closely mimics the silicon nanostructure. This follows research on similar solid carbon precursor derived semi-crystalline graphene synthesis procedures and applies it to complex silicon nanostructures. This work examined the progression of the carbon, finding that it migrates through the thin film catalyst and forms the graphene only on the other side, and that the process can successfully be used to form 3D shaped graphene films. Semi-crystalline graphene has the possible application of being flexible transparent electrodes, and the 3D shaping opens the possibility of more complex configurations and applications.
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Fujii, Shintaro, Maxim Ziatdinov, Misako Ohtsuka, Koichi Kusakabe, Manabu Kiguchi, and Toshiaki Enoki. "Role of edge geometry and chemistry in the electronic properties of graphene nanostructures." Faraday Discuss. 173 (2014): 173–99. http://dx.doi.org/10.1039/c4fd00073k.

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The geometry and chemistry of graphene nanostructures significantly affects their electronic properties. Despite a large number of experimental and theoretical studies dealing with the geometrical shape-dependent electronic properties of graphene nanostructures, experimental characterisation of their chemistry is clearly lacking. This is mostly due to the difficulties in preparing chemically-modified graphene nanostructures in a controlled manner and in identifying the exact chemistry of the graphene nanostructure on the atomic scale. Herein, we present scanning probe microscopic and first-principles characterisation of graphene nanostructures with different edge geometries and chemistry. Using the results of atomic scale electronic characterisation and theoretical simulation, we discuss the role of the edge geometry and chemistry on the electronic properties of graphene nanostructures with hydrogenated and oxidised linear edges at graphene boundaries and the internal edges of graphene vacancy defects. Atomic-scale details of the chemical composition have a strong impact on the electronic properties of graphene nanostructures,i.e., the presence or absence of non-bonding π states and the degree of resonance stability.
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Wu, Shiyun, Kaimin Fan, Minpin Wu, and Guangqiang Yin. "Two-dimensional MnO2/graphene hybrid nanostructures as anode for lithium ion batteries." International Journal of Modern Physics B 30, no. 27 (October 17, 2016): 1650208. http://dx.doi.org/10.1142/s0217979216502088.

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Using density functional theory, we have investigated the adsorption and diffusion of lithium on the two-dimensional MnO2/graphene hybrid nanostructures. The simulation results show that the adsorption energy is increased compared with pure graphene and monolayer MnO2. At the same time, the diffusion barrier is greatly reduced as lithium diffuses on the graphene side. The results indicate that the MnO2/graphene hybrid nanostructure can be used as a good anode material for lithium ion batteries.
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Tamm, Aile, Tauno Kahro, Helle-Mai Piirsoo, and Taivo Jõgiaas. "Atomic-Layer-Deposition-Made Very Thin Layer of Al2O3, Improves the Young’s Modulus of Graphene." Applied Sciences 12, no. 5 (February 27, 2022): 2491. http://dx.doi.org/10.3390/app12052491.

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Nanostructures with graphene make them highly promising for nanoelectronics, memristor devices, nanosensors and electrodes for energy storage. In some devices the mechanical properties of graphene are important. Therefore, nanoindentation has been used to measure the mechanical properties of polycrystalline graphene in a nanostructure containing metal oxide and graphene. In this study the graphene was transferred, prior to the deposition of the metal oxide overlayers, to the Si/SiO2 substrate were SiO2 thickness was 300 nm. The atomic layer deposition (ALD) process for making a very thin film of Al2O3 (thickness comparable with graphene) was applied to improve the elasticity of graphene. For the alumina film the Al(CH3)3 and H2O were used as the precursors. According to the micro-Raman analysis, after the Al2O3 deposition process, the G-and 2D-bands of graphene slightly broadened but the overall quality did not change (D-band was mostly absent). The chosen process did not decrease the graphene quality and the improvement in elastic modulus is significant. In case the load was 10 mN, the Young’s modulus of Si/SiO2/Graphene nanostructure was 96 GPa and after 5 ALD cycles of Al2O3 on graphene (Si/SiO2/Graphene/Al2O3) it increased up to 125 GPa. Our work highlights the correlation between nanoindentation and defects appearance in graphene.
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Wang, Wei, Shirui Guo, Isaac Ruiz, Mihrimah Ozkan, and Cengiz S. Ozkan. "Synthesis of Three Dimensional Carbon Nanostructure Foams for Supercapacitors." MRS Proceedings 1451 (2012): 85–90. http://dx.doi.org/10.1557/opl.2012.1330.

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ABSTRACTIn this work, we demonstrated the growth of three dimensional graphene/carbon nanotubes hybrid carbon nanostructures on metal foam through a one-step chemical vapor deposition (CVD). The as-grown three dimensional carbon nanostructure foams can be potentially used as the electrodes of energy storage devices such as supercapacitors and batteries. During the CVD process, the carbon nanostructures are grown on highly porous nickel foam to form a high surface area 3-D carbon nanostructure by introducing a mixture precursor gases (H2, C2H2). The surface morphology was investigated by scanning electron microscopy (SEM) and the results demonstrated relatively homogeneous and densely packed 3-D carbon nanostructure. The quality was characterized by Raman spectroscopy. To further increase the capacitive capability the supercapacitors were fabricated based on the electrodes of carbon nanostructure foam and cyclic voltammetry, charge-discharge, and electrochemical impedance spectroscopy (EIS) were conducted to determine their performance.
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Bi, Kaixi, Jiliang Mu, Wenping Geng, Linyu Mei, Siyuan Zhou, Yaokai Niu, Wenxiao Fu, Ligang Tan, Shuqi Han, and Xiujian Chou. "Reliable Fabrication of Graphene Nanostructure Based on e-Beam Irradiation of PMMA/Copper Composite Structure." Materials 14, no. 16 (August 17, 2021): 4634. http://dx.doi.org/10.3390/ma14164634.

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Graphene nanostructures are widely perceived as a promising material for fundamental components; their high-performance electronic properties offer the potential for the construction of graphene nanoelectronics. Numerous researchers have paid attention to the fabrication of graphene nanostructures, based on both top-down and bottom-up approaches. However, there are still some unavoidable challenges, such as smooth edges, uniform films without folds, and accurate dimension and location control. In this work, a direct writing method was reported for the in-situ preparation of a high-resolution graphene nanostructure of controllable size (the minimum feature size is about 15 nm), which combines the advantages of e-beam lithography and copper-catalyzed growth. By using the Fourier infrared absorption test, we found that the hydrogen and oxygen elements were disappearing due to knock-on displacement and the radiolysis effect. The graphene crystal is also formed via diffusion and the local heating effect between the e-beam and copper substrate, based on the Raman spectra test. This simple process for the in-situ synthesis of graphene nanostructures has many promising potential applications, including offering a way to make nanoelectrodes, NEMS cantilever resonant structures, nanophotonic devices and so on.
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Li, Jia Ye, Jin Feng Zhu, and Qing H. Liu. "Tunable Properties of Three-Dimensional Graphene-Loaded Plasmonic Absorber Using Plasmonic Nanoparticles." Materials Science Forum 860 (July 2016): 29–34. http://dx.doi.org/10.4028/www.scientific.net/msf.860.29.

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We demonstrate a three-dimensional nanostructure design by combining graphene and conventional plasmonic nanostructures, to achieve the high absorbance in the visible region. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. Comparing the results of two structures which is based on different materials, Gold and Silver. The structure made of Silver present a better performance. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.
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Loginos, Panagiotis, Anastasios Patsidis, and Vasilios Georgakilas. "UV-Cured Poly(Ethylene Glycol) Diacrylate/Carbon Nanostructure Thin Films. Preparation, Characterization, and Electrical Properties." Journal of Composites Science 4, no. 1 (January 1, 2020): 4. http://dx.doi.org/10.3390/jcs4010004.

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Carbon nanoallotropes such as carbon nanotubes, graphene, and their derivatives have been combined with a plethora of polymers in the last years to develop new composite materials with interesting properties and applications. However, the area of photopolymer composites with carbon nanostructures has not been analogously explored. In the present article, we study the photopolymerization of poly(ethylene glycol)diacrylate (PEGDA) enriched with different carbon nanoallotropes like graphene, pristine and chemically modified carbon nanotubes (CNTs and fCNTs), and a hybrid of graphene and CNTs. The products were characterized by several microscopic and spectroscopic techniques and the electrical conductivity was studied as a function of the concentrations of carbon nanoallotropes. In general, stable thin films were produced with a concentration of carbon nanostructures up to 8.5%, although the addition of carbon nanostructures in PEGDA decreases the degree of photopolymerization, and PEDGA/carbon nanostructure composites showed electrical conductivity at a relatively low percentage.
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Dissertations / Theses on the topic "Nanostructure - Graphene"

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France-Lanord, Arthur. "Transport électronique et thermique dans des nanostructures." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS566/document.

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La miniaturisation continue des composants électroniques rend indispensable la connaissance des mécanismes de transport à l’échelle nanométrique. Alors que les processus simples de conduction dans les matériaux homogènes sont bien assimilés, la compréhension du transport à l’échelle nanométrique dans les systèmes hétérogènes reste à améliorer. Par exemple, le couplage entre courant, résistance et flux de chaleur dans des nanostructures doit être clarifié. Dans ce contexte, le sujet de thèse est centré autour du développement et de l’application de méthodes de calcul avancées pour la prédiction des propriétés de transport électronique et thermique à l’échelle nanométrique. Dans une première partie, nous avons paramétré un modèle de potentiel inter-atomique classique adapté à la description de systèmes multicomposants, afin de modéliser les propriétés structurelles, vibratoires et de transport de chaleur de la silice, ainsi que du silicium. Pour ce faire, une approche d’optimisation automatisée et reproductible a été mise en place. En guise d’exemple, nous avons calculé la dépendance en température de la résistance de Kapitza pour le système silice amorphe - silicium cristallin, ce qui a permis de souligner l’importance d’une description structurelle précise de l’interface. Dans une seconde partie, nous avons étudié la décomposition modale de la conductivité thermique du graphène supporté par un substrat de silice amorphe. Plus précisément, l’influence de l’état de surface (hydroxilation, etc) sur le transport thermique a été quantifiée. Le rôle déterminant des excitations collectives de phonons a été mis au jour. Finalement, dans une dernière partie, les propriétés de transport électronique du graphène supporté par une bi-couche de silice, système récemment observé expérimentalement, ont été étudiées. L’influence d’ondulations dans la couche de graphène ou dans le substrat, souvent présentes dans les échantillons réels et dont l’amplitude et la longueur d’onde peuvent être contrôlées, a été dégagée. Nous avons également modélisé le champ électrique généré par une grille, et déterminé son incidence sur le transport électronique
The perpetual shrinking of microelectronic devices makes it crucial to have a proper understanding of transport mechanisms at the nanoscale. While simple effects are now well understood in homogeneous materials, the understanding of nanoscale transport in heterosystems needs to be improved. For instance, the relationship between current, resistance, and heat flux in nanostructures remains to be clarified. In this context, the subject of the thesis is centered around the development and application of advanced numerical methods used to predict electronic and thermal conductivities of nanomaterials. This manuscript is divided into three parts. We begin with the parameterization of a classical interatomic potential, suitable for the description of multicomponent systems, in order to model the structural, vibrational, and thermal transport properties of both silica and silicon. A well-defined, reproducible, and automated optimization procedure is derived. As an example, we evaluate the temperature dependence of the Kapitza resistance between amorphous silica and crystalline silicon, and highlight the importance of an accurate description of the structure of the interface. Then, we have studied thermal transport in graphene supported on amorphous silica, by evaluating the mode-wise decomposition of thermal conductivity. The influence of hydroxylation on heat transport, as well as the significant role played by collective excitations of phonons, have come to light. Finally, electronic transport properties of graphene supported on quasi-two-dimensional silica, a system recently observed experimentally, have been investigated. The influence on transport properties of ripples in the graphene sheet or in the substrate, which often occur in samples and whose amplitude and wavelength can be controlled, has been evaluated. We have also modeled electrostatic gating, and its impact on electronic transport
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Celis, Retana Arlensiú Eréndira. "Gap en graphène sur des surfaces nanostructurées de SiC et des surfaces vicinales de métaux nobles." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS417/document.

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L'électronique basée sur le graphène fait face à un verrou technologique, qui est l'absence d'une bande interdite (gap) permettant une commutation entre les états logiques allumé et éteint. Les nano-rubans de graphène rendent possible l'obtention de ce gap mais il est difficile de produire de tels rubans avec une largeur précise à l'échelle atomique et des bords bien ordonnés. Le confinement électronique est une façon élégante d'ouvrir un gap et peut en principe être réglé en ajustant la largeur des nano-rubans. Cette thèse est consacrée à la compréhension de l'ouverture du gap par nano-structuration. Nous avons suivi deux approches: l'introduction d'un potentiel super-périodique sur le graphène par des substrats vicinaux de métaux nobles et le confinement électronique dans des nano-rubans sur des facettes artificielles du SiC. Des potentiels super-périodiques ont été introduits avec deux substrats nano-structurés: l'Ir(332) et un cristal courbé de Pt(111) multi-vicinale. Le graphène modifie les marches initiales des substrats et les transforme en une succession de terrasses (111) et de régions d'accumulation de marches, observés par STM. La nano-structuration du substrat induit alors un potentiel super-périodique dans le graphène entraînant l'ouverture de gaps sur la bande π du graphène observée par ARPES, ce qui est cohérent avec la périodicité structurale observé par STM et LEED. Les gaps peuvent être convenablement expliqués par un modèle de type hamiltonien de Dirac; ce dernier nous permet de retrouver la force du potentiel à la jonction entre les terrasses (111) et la région d'accumulation des marches. La force du potentiel dépend du substrat, de la périodicité associée à la surface et du type de bord des marches (soit type A ou B). Nous avons aussi changé le potentiel de surface en intercalant du Cu sur l'Ir(332), qui reste préférentiellement au niveau de l'accumulation des marches. La surface présente des régions dopées n alors que les régions non-intercalées restent dopées p, conduisant à une succession de rubans dopés n et p pour une même couche de graphène continue. La seconde approche pour contrôler le gap est par confinement électronique dans des nanorubans de graphène synthétisés sur du SiC. Ces rubans sont obtenus sur des facettes du SiC ordonnées périodiquement. Comme l'ouverture d'un gap d'origine inconnue avait été observée par ARPES, nous avons réalisé les premières études atomiquement résolues par STM. Nous démontrons la régularité et la chiralité des bords, nous localisons précisément les nanorubans de graphène sur les facettes et nous identifions des mini-facettes sur du SiC. Afin de comprendre le couplage entre le graphène et le substrat, nous avons étudié une coupe transversale par STEM/EELS, en complément des études par ARPES et STM/STS. Nous observons que la facette (1-107) où le graphène se trouve présente un sub-facettage sur les extrémités haute et basse. Le sub-facettage comprend des mini-terrasses (0001) et des mini-facettes (1-105). Le graphène s'étend tout au long du la région sub-facettée, et est couplé au substrat dans les mini-terrasses (0001), ce qui le rend semi-conducteur. En revanche, le graphène au-dessus des mini-facettes (1-105) est découplé du substrat mais présente un gap observé par EELS, et compatible avec les observations faites par ARPES. L'origine du gap est expliquée par le confinement électronique sur des nano-rubans de graphène de 1 - 2 nm de largeur localisés sur ces mini-facettes (1-105)
The major challenge for graphene-based electronic applications is the absence of the band-gap necessary to switch between on and off logic states. Graphene nanoribbons provide a route to open a band-gap, though it is challenging to produce atomically precise nanoribbon widths and well-ordered edges. A particularly elegant method to open a band-gap is by electronic confinement, which can in principle be tuned by adjusting the nanoribbon width. This thesis is dedicated to understanding the ways of opening band-gaps by nanostructuration. We have used two approaches: the introduction of a superperiodic potential in graphene on vicinal noble metal substrates and the electronic confinement in artificially patterned nanoribbons on SiC. Superperiodic potentials on graphene have been introduced by two nanostructured substrates, Ir(332) and a multivicinal curved Pt(111) substrate. The growth of graphene modifies the original steps of the pristine substrates and transforms them into an array of (111) terraces and step bunching areas, as observed by STM. This nanostructuration of the underlying substrate induces the superperiodic potential on graphene that opens mini-gaps on the π band as observed by ARPES and consistent with the structural periodicity observed in STM and LEED. The mini-gaps are satisfactorily explained by a Dirac-hamiltonian model, that allows to retrieve the potential strength at the junctions between the (111) terraces and the step bunching. The potential strength depends on the substrate, the surface periodicity and the type of step-edge (A or B type). The surface potential has also been modified by intercalating Cu on Ir(332), that remains preferentially on the step bunching areas, producing there n-doped ribbons, while the non-intercalated areas remain p-doped, giving rise to an array of n- and p- doped nanoribbons on a single continuous layer. In the second approach to control the gap, we have studied the gap opening by electronic confinement in graphene nanoribbons grown on SiC. These ribbons are grown on an array of stabilized sidewalls on SiC. As a band-gap opening with unclear atomic origin had been observed by ARPES, we carried-out a correlated study of the atomic and electronic structure to identify the band gap origin. We performed the first atomically resolved study by STM, demonstrating the smoothness and chirality of the edges, finding the precise location of the metallic graphene nanoribbon on the sidewalls and identifying an unexpected mini-faceting on the substrate. To understand the coupling of graphene to the substrate, we performed a cross-sectional study by STEM/EELS, complementary of our ARPES and STM/STS studies. We observe that the (1-107) SiC sidewall facet is sub-faceted both at its top and bottom edges. The subfacetting consists of a series of (0001) miniterraces and (1-105) minifacets. Graphene is continuous on the whole subfacetting region, but it is coupled to the substrate on top of the (0001) miniterraces, rendering it there semiconducting. On the contrary, graphene is decoupled on top of the (1-105) minifacets but exhibits a bandgap, observed by EELS and compatible with ARPES observations. Such bandgap is originated by electronic confinement in the 1 - 2 nm width graphene nanoribbons that are formed over the (1-105) minifacets
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Chernozatonskii, L. A., and V. A. Demin. "Nanotube Connections in Bilayer Graphene with Elongated Holes." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35460.

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Structures, stability and electronic properties of AA-stacking bigraphene with holes are studied using molecular mechanic and DFT method calculations. It has been shown the zig-zag edges of considered elon-gated holes lead to armchair sp2-nanotube-type connection between these two edges forming all sp2-structure. We consider similar periodic structures with (n,n) nanotubes formed among elongated holes and connected with bigraphene fragments, which edges are also closed edges. The stability and electronic prop-erties of these structures are investigated. Band structures of considered materials have energy gaps 0.20-0.27 eV in the direction of tube axes through jumpers on the connections, and Dirac-like point views in the opposite direction. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35460
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Das, Santanu. "Carbon Nanostructure Based Electrodes for High Efficiency Dye Sensitize Solar Cell." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/678.

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Synthesis and functionalization of large-area graphene and its structural, electrical and electrochemical properties has been investigated. First, the graphene films, grown by thermal chemical vapor deposition (CVD), contain three to five atomic layers of graphene, as confirmed by Raman spectroscopy and high-resolution transmission electron microscopy. Furthermore, the graphene film is treated with CF4 reactive-ion plasma to dope fluorine ions into graphene lattice as confirmed by X-ray photoelectron spectroscopy (XPS) and UV-photoemission spectroscopy (UPS). Electrochemical characterization reveals that the catalytic activity of graphene for iodine reduction enhanced with increasing plasma treatment time, which is attributed to increase in catalytic sites of graphene for charge transfer. The fluorinated graphene is characterized as a counter-electrode (CE) in a dye-sensitized solar cell (DSSC) which shows ~ 2.56% photon to electron conversion efficiency with ~11 mAcm−2 current density. Second, the large scale graphene film is covalently functionalized with HNO3 for high efficiency electro-catalytic electrode for DSSC. The XPS and UPS confirm the covalent attachment of C-OH, C(O)OH and NO3- moieties with carbon atoms through sp2-sp3 hybridization and Fermi level shift of graphene occurs under different doping concentrations, respectively. Finally, CoS-implanted graphene (G-CoS) film was prepared using CVD followed by SILAR method. The G-CoS electro-catalytic electrodes are characterized in a DSSC CE and is found to be highly electro-catalytic towards iodine reduction with low charge transfer resistance (Rct ~5.05 Wcm2) and high exchange current density (J0~2.50 mAcm-2). The improved performance compared to the pristine graphene is attributed to the increased number of active catalytic sites of G-CoS and highly conducting path of graphene. We also studied the synthesis and characterization of graphene-carbon nanotube (CNT) hybrid film consisting of graphene supported by vertical CNTs on a Si substrate. The hybrid film is inverted and transferred to flexible substrates for its application in flexible electronics, demonstrating a distinguishable variation of electrical conductivity for both tension and compression. Furthermore, both turn-on field and total emission current was found to depend strongly on the bending radius of the film and were found to vary in ranges of 0.8 – 3.1 V/μm and 4.2 – 0.4 mA, respectively.
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Rhoads, Daniel Joseph. "A Mathematical Model of Graphene Nanostructures." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1438978423.

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Federspiel, Francois. "Etude optique du transfert d'énergie entre une nanostructure semiconductrice unique et un feuillet de graphène." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE015/document.

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Mes travaux de thèse portent sur l’interaction de type FRET (tranfert d’énergie résonant de Förster) entre une nanostructure semiconductrice colloïdale individuelle et le graphène. La première partie concerne l’établissement de la théorie du FRET et ce pour plusieurs types de nanostructures. Vient ensuite la partie expérimentale, à commencer par le montage optique ainsi que les méthodes d’analyse, tant pour la spectroscopie que pour la photoluminescence. Par la suite, nous décrivons les résultats obtenus pour divers types de nanocristaux sphériques en interaction directe avec le graphène (incluant des multicouches) : le transfert d’énergie a des effets drastiques sur la photoluminescence mais aussi sur le clignotement des nanocristaux. Puis nous étudions la dépendance du FRET avec la distance ; dans le cas des boîtes quantiques, nous observons une loi en 1/z^4. Par contre, dans le cas de nanoplaquettes, la fonction est plus complexe et dépend de la température
My PhD subject is the FRET interaction (Förster-like resonant energy transfer) between single colloidal semiconductor nanostructures and graphene. The first part is about the development of the interaction theory with the graphene for several types of nanostructures. Then comes the experimental part, and firstly the optical setup together with the analysis methods, for both spectroscopy and photoluminescence. After that, we describe our results about different types of spherical nanocrystals directly interacting with graphene (which can be multilayer) : the energy transfer has a huge effect on the photoluminescence, as well as the blinking behaviour of the nanocrystals. Then we measure the dependency of the energy transfer as a function the distance ; in the case of quantum dots, we observe a 1/z^4 law. On another hand, in the case of nanoplatelets, the function is more complex and depends on the temperature
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CURCIO, DAVIDE. "Growth and Properties of Graphene-Based Materials." Doctoral thesis, Università degli Studi di Trieste, 2017. http://hdl.handle.net/11368/2908114.

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In this thesis, I have focused on graphene-based nanostructures as a versatile means of manipulating the electronic properties of graphene, while working with objects perfect at the atomic level. This is the nanotechnological approach, where we exploit the infinite possibilities of making small things with new materials. For these reasons, I concentrated my research efforts to graphene-based nanomaterials, because graphene is one of the most exciting materials we have to date, and because manipulation of surfaces at the nano-level is what allows us to make new materials today. In this thesis, I will show how we have created and studied new graphene-based nanostructures by employing cutting-edge surface science techniques. Most of the experimental data we have acquired has been given a new light by powerful Density Functional Theory calculations, that allow for an approach where hardly accessible data (experimentally) becomes indirectly known through numerical calculations, while providing valuable feedback for further aimed calculations. I will show how we have undertaken a route that takes us from a detailed study of how carbon monomers, the building blocks of graphene, come to exist on an Ir(1 1 1) surface after ethylene dissociation. Next, simple nanostructures have been ex- ploited, so that the properties of a preexisting graphene layer are manipulated by intercalating different metals between graphene and the substrate. Then I will discuss an experiment where graphene was grown on a highly anisotropic substrate, Ru(1 0 1 0), which proved to be an extremely rich system, giving rise to several self-assembled graphene nanostructures, including nanoribbons and one-dimensional quasi free-standing graphene waves. Then, we will progress to what are commonly perceived as being proper graphene-based nanostructures. We have, in fact, managed to create size selected graphene nanodomes on Ir(1 1 1) using coronene as a precursor, and we have understood many details of the dynamics in the formation of these carbon-based nanostructures, discovering that in certain steps of the reaction they lift from the surface and rotate, before settling in the definitive adsorption position. Furthermore, while performing similar experiments on pentacene (a semiconducting molecule, used the fabrication of molecular FETs) on Ir(1 1 1), we have discovered that the molecules exhibit a reversible dehydrogenation, allowing for a switch between semiconducting molecules and minimalistic graphene nanoribbons, only one aromatic ring wide. Finally, a size-selected nanocluster source system will be described. In parallel with my research activity, I have been profoundly involved in the commissioning of such a machine that is currently capable of producing size selected nanoclusters.
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Seo, Michael. "Plasma-assisted nanofabrication of vertical graphene- and silicon-based nanomaterials and their applications." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12285.

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Scarcity of physical resources, increasing concerns for safety and hazardous waste disposal which affects the environment drove the current nanoscience research to focus on developing low-cost, green and environmentally friendly method of obtaining nanomaterials. Yet, developing such smart and innovative processes is at premature stage. Over a few decades, many nanomaterials have been found and investigated. Amongst many nanomaterials, carbon and silicon nanomaterials attracted immense attention due to their abundance, low cost, unique and tunable properties which are promising for many applications. However, making nanostructure with uniformity and desirable properties is often difficult due to a lack of precise control which inherits from fabrication process. Furthermore, many techniques cannot satisfy green and environmentally friendly synthesis of mentioned nanomaterials. Therefore, efficient, effective and environmentally friendly way to create mentioned nanostructures with tunable properties remains a major challenge. Over a few decades, many investigations demonstrated that plasma technique can create uniform nanostructure in an environmentally friendly way which holds great promise as a versatile nanofabrication tool. Therefore, in this thesis, I investigate the plasma aided fabrication of Nobel Prize winning graphene related material called vertical graphenes will be discussed in details. Vertical graphene features are expected to be promising for a host of applications, from energy storage devices to gas detection. Therefore, I will explore the potential of vertical graphenes in diverse applications. Furthermore, green way of creating vertical graphenes using natural precursors from different states of matter will also be investigated. Following on from investigation of vertical graphenes, I will also demonstrate controllable, green synthesis of silicon based nanostructures without hazardous silicon precursor material using plasma-assisted methods.
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Kim, Junseok. "Improved Properties of Poly (Lactic Acid) with Incorporation of Carbon Hybrid Nanostructure." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/81415.

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Poly(lactic acid) is biodegradable polymer derived from renewable resources and non-toxic, which has become most interested polymer to substitute petroleum-based polymer. However, it has low glass transition temperature and poor gas barrier properties to restrict the application on hot contents packaging and long-term food packaging. The objectives of this research are: (a) to reduce coagulation of graphene oxide/single-walled carbon nanotube (GOCNT) nanocomposite in poly(lactic acid) matrix and (b) to improve mechanical strength and oxygen barrier property, which extend the application of poly(lactic acid). Graphene oxide has been found to have relatively even dispersion in poly(lactic acid) matrix while its own coagulation has become significant draw back for properties of nanocomposite such as gas barrier, mechanical properties and thermo stability as well as crystallinity. Here, single-walled carbon nanotube was hybrid with graphene oxide to reduce irreversible coagulation by preventing van der Waals of graphene oxide. Mass ratio of graphene oxide and carbon nanotube was determined as 3:1 at presenting greatest performance of preventing coagulation. Four different weight percentage of GOCNT nanocomposite, which are 0.05, 0.2, 0.3 and 0.4 weight percent, were composited with poly(lactic acid) by solution blending method. FESEM morphology determined minor coagulation of GOCNT nanocomopsite for different weight percentage composites. Insignificant crystallinity change was observed in DSC and XRD data. At 0.4 weight percent, it prevented most of UV-B light but was least transparent. GOCNT nanocomposite weight percent was linearly related to ultimate tensile strength of nanocomposite film. The greatest ultimate tensile strength was found at 0.4 weight percent which is 175% stronger than neat poly(lactic acid) film. Oxygen barrier property was improved as GOCNT weight percent increased. 66.57% of oxygen transmission rate was reduced at 0.4 weight percent compared to neat poly(lactic acid). The enhanced oxygen barrier property was ascribed to the outstanding impermeability of hybrid structure GOCNT as well as the strong interfacial adhesion of GOCNT and poly(lactic acid) rather than change of crystallinity. Such a small amount of GOCNT nanocomposite improved mechanical strength and oxygen barrier property while there were no significant change of crystallinity and thermal behavior found.
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Geng, Yan. "Preparation and characterization of graphite nanoplatelet, graphene and graphene-polymer nanocomposites /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?MECH%202009%20GENG.

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Books on the topic "Nanostructure - Graphene"

1

Mikhailov, Sergey. Physics and applications of graphene: Theory. Rijeka, Croatia: InTech, 2011.

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Jorio, A. Raman spectroscopy in graphene related systems. Weinheim, Germany: Wiley-VCH, 2011.

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Kābon nanochūbu, gurafen. Tōkyō: Kyōritsu Shuppan, 2012.

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Pribat, Didier, Young Hee Lee, and M. Razeghi. Carbon nanotubes, graphene, and associated devices III: 1-2 and 4 August 2010, San Diego, California, United States. Edited by SPIE (Society). Bellingham, Wash: SPIE, 2010.

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Susumo, Saitō, and Zettl Alex, eds. Carbon nanotubes: Quantum cylinders of graphene. Amsterdam, The Netherlands: Elsevier, 2008.

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Enoki, Toshiaki, C. N. R. Rao, and Swapan K. Pati. Graphene and its fascinating attributes. New Jersey: World Scientific, 2011.

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Ali, Nasar, Mahmood Aliofkhazraei, William I. Milne, Cengiz S. Ozkan, and Stanislaw Mitura. Graphene Science Handbook: Nanostructure and Atomic Arrangement. Taylor & Francis Group, 2016.

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Ali, Nasar, Mahmood Aliofkhazraei, William I. Milne, Cengiz S. Ozkan, and Stanislaw Mitura. Graphene Science Handbook: Nanostructure and Atomic Arrangement. Taylor & Francis Group, 2016.

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Banadaki, Yaser M., and Safura Sharifi. Graphene Nanostructures. Jenny Stanford Publishing, 2019. http://dx.doi.org/10.1201/9780429022210.

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Graphene Nanostructures. Taylor & Francis Group, 2019.

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Book chapters on the topic "Nanostructure - Graphene"

1

Terasawa, Tomo-o., and Koichiro Saiki. "Graphene: Synthesis and Functionalization." In Nanostructure Science and Technology, 101–32. Tokyo: Springer Japan, 2017. http://dx.doi.org/10.1007/978-4-431-56496-6_4.

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Hatakeyama, Kazuto, Shinya Hayami, and Yasumichi Matsumoto. "Graphene Oxide Based Electrochemical System for Energy Generation." In Nanostructure Science and Technology, 331–46. Tokyo: Springer Japan, 2017. http://dx.doi.org/10.1007/978-4-431-56496-6_12.

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Mansouri, N., and S. Bagheri. "Graphene Hydrogel Novel Nanostructure as a Scaffold." In IFMBE Proceedings, 99–102. Singapore: Springer Singapore, 2015. http://dx.doi.org/10.1007/978-981-10-0266-3_20.

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Lu, An-Hui, Guang-Ping Hao, Qiang Sun, Xiang-Qian Zhang, and Wen-Cui Li. "Chemical Synthesis of Carbon Materials with Intriguing Nanostructure and Morphology." In Chemical Synthesis and Applications of Graphene and Carbon Materials, 115–57. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2016. http://dx.doi.org/10.1002/9783527648160.ch7.

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Talat, Mahe, and O. N. Srivastava. "Deployment of New Carbon Nanostructure: Graphene for Drug Delivery and Biomedical Applications." In Advances in Nanomaterials, 383–95. New Delhi: Springer India, 2016. http://dx.doi.org/10.1007/978-81-322-2668-0_11.

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Naseem, Z., K. Sagoe-Crentsil, and W. Duan. "Graphene-Induced Nano- and Microscale Modification of Polymer Structures in Cement Composite Systems." In Lecture Notes in Civil Engineering, 527–33. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_56.

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AbstractRedispersible polymers such as ethylene–vinyl acetate copolymer (EVA) have attracted attention in construction due to their enhanced flexural strength, adhesion, flexibility and resistance against water penetration. However, EVA particles cluster in a highly alkaline cementitious matrix and exhibit poor interaction with the cement matrix. The underlying mechanism of poor dispersibility of EVA is attributed to hydrophobic groups of polymers, a variation in the adsorption rate and molecular diffusion to the interface where they cluster together. This phenomenon can negatively affect the fresh properties of cement and produce a weak microstructure, adversely affecting the resulting composites’ performance. This study highlights how graphene oxide (GO) nanomaterial alters the nano- and microscale structural characteristics of EVA to minimize the negative effects. Transmission electron microscopy (TEM) revealed that the GO sheets modify EVA’s clustered nanostructure and disperse it through electrostatic and steric interactions. Furthermore, scanning electron microscopy (SEM) confirmed altered microscale structural characteristics (viz. surface features) by GO. The altered and enhanced material scale engineering performance, such as the compressive strength of the resulting cement composite, was notable.
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Ortega-Amaya, R., M. A. Pérez-Guzmán, and M. Ortega-López. "Chapter 2. Production of Carbon Nanostructure/Graphene Oxide Composites by Self-assembly and Their Applications." In All-carbon Composites and Hybrids, 31–52. Cambridge: Royal Society of Chemistry, 2021. http://dx.doi.org/10.1039/9781839162718-00031.

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Kouini, Benalia, and Hossem Belhamdi. "Graphene and Graphene Oxide as Nanofiller for Polymer Blends." In Carbon Nanostructures, 231–57. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-30207-8_9.

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Kholmanov, I. N., C. Soldano, G. Faglia, and G. Sberveglieri. "Engineering of Graphite Bilayer Edges by Catalyst-Assisted Growth of Curved Graphene Structures." In Carbon Nanostructures, 209–13. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-20644-3_26.

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Silva, Martin Kássio Leme, and Ivana Cesarino. "Graphene Functionalization and Nanopolymers." In Carbon Nanostructures, 157–78. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9057-0_6.

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Conference papers on the topic "Nanostructure - Graphene"

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Resnick, Alex, Jungkyu Park, Biya Haile, and Eduardo B. Farfán. "Three-Dimensional Printing of Carbon Nanostructures." In ASME 2019 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/imece2019-11411.

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Abstract Multi-layered carbon nanostructures are the next leap for many advanced consumer and industrial applications that require both high strength and uniquely high electrical and thermal properties. Applications of three-dimensional (3D) carbon nanostructures have already been theorized to include wearable technology, processor chip heat transfer material, and flexible electronics. 3D carbon nanostructures appear in the form of carbon nanotubes (CNTs) and layered graphene tiers, however, many structures previously examined have been limited to one or two graphene layers or non-repeatable structured patterns. Many of the electrical and thermal properties of CNTs are still being investigated, but the initial studies demonstrate promising results such as the thermal conductivity ranging in the thousands W/m-K. Developing new ways to fabricate these structures at a reasonable cost has become a primary focus for graphene-based research. In this study, 3D carbon nanostructure samples are 3D printed using laser lithography, then a series of high temperature furnace burns and Nickel Chemical Vapor Deposition (CVD) is utilized to leave a previously multi-species structure as a solely carbon-species structure with mostly carbon sp-2 bonds. CVD has proven to be a leading method for forming graphene due to the ability to control graphene nucleation across larger surfaces and structures. Nanoscale 3D printing of carbon structures also allows for a great degree of freedom towards the creation of repeatable patterns or structures that are currently trying to be achieved in other studies. This study employs the use of controlled cleanroom environments with cutting edge technology and machines to fabricate the 3D carbon nanostructures.
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Chu, Hung-Yao, Judy M. Obliosca, Pen-Cheng Wang, and Fan-Gang Tseng. "Strong SERS biosensor with gold nanostructure sandwiched on graphene." In 2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2013. http://dx.doi.org/10.1109/memsys.2013.6474394.

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Trenikhin, M. V., and V. A. Drozdov. "Nanostructure analysis of the graphene layers of carbon black." In 21ST CENTURY: CHEMISTRY TO LIFE. AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5122909.

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Nakarmi, Sushan, and V. U. Unnikrishnan. "Influence of Strain States on the Thermal Transport Properties of Single and Multiwalled Carbon Nanostructures." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-88620.

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The increasing demand for system miniaturization and high power density energy produces excessive thermal loads on electronic devices with significant mechanical strain. Carbon Nanotubes (CNTs) based devices are found to have excellent thermal transport properties that makes them attractive for thermal management of these miniaturized nano-electronic devices under extreme environments. These conductive nanostructure (carbon nanotubes, graphene, etc.) are often embedded in polymers or other high-strain alloys (the matrix phase), and are used as bridging materials for conductivity (electrical and thermal) with strain resiliency. The effect of strain on the thermal transport properties of these nanostructures have often been overlooked and will be the focus of this work. The thermal conductivity of the nanostructure is obtained in LAMMPS using the Heat-Bath method, which is a reverse non-equilibrium molecular dynamics (RNEMD) simulation strategy. In RNEMD, constant amount of heat is added to and removed from hot and cold regions and the resultant temperature gradient is measured. The effect of strain on the thermal conductivity of the single and multiwalled nanostructures of various configurations will be discussed with specific emphasis on the phonon density of states of nanotubes at different strain states.
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Rahman, Shaharin Fadzli Abd, Abd Manaf Hashim, and Seiya Kasai. "Fabrication and transport performance of three-branch junction graphene nanostructure." In 2012 International Conference on Enabling Science and Nanotechnology (ESciNano). IEEE, 2012. http://dx.doi.org/10.1109/escinano.2012.6149707.

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Ghadiri, Yashar, and Mohammad Najafi. "Giant Kerr nonlinearity in a quantized four-level graphene nanostructure." In Novel Optical Materials and Applications. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/noma.2016.notu3d.6.

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Junjun Cheng, Jinfeng Zhu, Shuang Yan, Lirong Zhang, and Qinghuo Liu. "A novel electro-optic modulator with metal/dielectric/graphene nanostructure: Simulation of isotropic and anisotropic graphene." In 2016 Progress in Electromagnetic Research Symposium (PIERS). IEEE, 2016. http://dx.doi.org/10.1109/piers.2016.7735311.

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Peng, Jingyang, Benjamin P. Cumming, and Min Gu. "MIR spin angular momentum detection by a chiral graphene plasmonic nanostructure." In Frontiers in Optics. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/fio.2018.fw5e.4.

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Balois, Maria Vanessa C., Norihiko Hayazawa, Satoshi Yasuda, Katsuyoshi Ikeda, Bo Yang, Emiko Kazuma, Yasayuki Yokota, Yousoo Kim, and Takuo Tanaka. "Plasmon activated forbidden phonon modes in defect-free graphene by tip-enhanced nano-confined light." In JSAP-OSA Joint Symposia. Washington, D.C.: Optica Publishing Group, 2018. http://dx.doi.org/10.1364/jsap.2018.18a_211b_5.

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Ohnishi, Masato, Katsuya Ohsaki, Yusuke Suzuki, Ken Suzuki, and Hideo Miura. "Nanostructure Dependence of the Electronic Conductivity of Carbon Nanotubes and Graphene Sheets." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-37277.

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In this study, the change of the resistivity of the CNT-dispersed resin was analyzed by applying a quantum chemical molecular dynamics and the first principle calculation. Various combinations of double-walled carbon nanotube structures were modeled for the analysis. The change of the band structure was calculated by changing the amplitude of the applied strain. It was found in some cases that the band structure changes drastically from a metallic structure to a semiconductive structure, and this result clearly indicated that the electronic conductivity of this MWCNT decreased significantly under tensile strain. It was also found that further application of the strain made a band gap in the band structure. This result indicated that the metallic CNT changes a semiconductive CNT due to the applied strain. The effect of the diameter of the zigzag type CNT on the critical strain of buckling deformation was analyzed under a uni-axial strain. In this analysis, the aspect ratio of each structure was fixed at 10. It was found that the critical strain decreased monotonically with the increase of the diameter. This was because that the flexural rigidity of a cylinder decreased with the increase of its diameter when the thickness of the wall of the cylinder is fixed. It was found that the critical strain decreased drastically from about 5% to 0.5% when the aspect ratio was changed from 10 to 30. Since the typical aspect ratio of CNTs often exceeds 1000, most CNTs show buckling deformation when an axial compressive strain was applied to the CNTs. Finally, the shape of six-membered ring of the CNT was found to be the dominant factor that determines the electronic band structure of a CNT. Next, the change of the band structure of a graphene sheet was analyzed by applying the abinitio calculation (Density functional theory). It was found that the fluctuation of the atomic distance among the six-membered ring is the most dominant factor of the electronic band structure. When the fluctuation exceeded about 10%, band gap appeared in the deformed six-membered ring, and thus, the electronic conductivity of the graphene sheet changes from metallic one to semiconductive one. It is therefore, possible to predict the change of the electronic conductivity of a CNT by considering the local shape of a six-membered ring in the deformed CNT.
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Reports on the topic "Nanostructure - Graphene"

1

Kim, Ki W. Graphene Nanostructures for Novel Spin Magnetic Device Applications. Fort Belvoir, VA: Defense Technical Information Center, December 2012. http://dx.doi.org/10.21236/ada580335.

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McCarty, Keven F., Xiaowang Zhou, Donald K. Ward, Peter A. Schultz, Michael E. Foster, and Norman Charles Bartelt. Predicting growth of graphene nanostructures using high-fidelity atomistic simulations. Office of Scientific and Technical Information (OSTI), September 2015. http://dx.doi.org/10.2172/1221517.

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