Готові списки джерел за темами / Binary superlattices

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Добірка наукової літератури з теми "Binary superlattices"

Автор: Grafiati

Опубліковано: 9 березня 2024

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Статті в журналах з теми "Binary superlattices"

Yun, Hongseok, and Taejong Paik. "Colloidal Self-Assembly of Inorganic Nanocrystals into Superlattice Thin-Films and Multiscale Nanostructures." Nanomaterials 9, no. 9 (September 1, 2019): 1243. http://dx.doi.org/10.3390/nano9091243.

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The self-assembly of colloidal inorganic nanocrystals (NCs) offers tremendous potential for the design of solution-processed multi-functional inorganic thin-films or nanostructures. To date, the self-assembly of various inorganic NCs, such as plasmonic metal, metal oxide, quantum dots, magnetics, and dielectrics, are reported to form single, binary, and even ternary superlattices with long-range orientational and positional order over a large area. In addition, the controlled coupling between NC building blocks in the highly ordered superlattices gives rise to novel collective properties, providing unique optical, magnetic, electronic, and catalytic properties. In this review, we introduce the self-assembly of inorganic NCs and the experimental process to form single and multicomponent superlattices, and we also describe the fabrication of multiscale NC superlattices with anisotropic NC building blocks, thin-film patterning, and the supracrystal formation of superlattice structures.

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Garus, Sebastian, and Michal Szota. "Occurence of Characteristic Peaks in Phononic Multilayer Structures." Revista de Chimie 69, no. 3 (April 15, 2018): 735–38. http://dx.doi.org/10.37358/rc.18.3.6188.

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In this paper the acoustic transmission properties of multilayer structures was analyzed. Were compared binary and aperiodic (Severin, Thue-Morse) superlattices, Calculations were performed using the Transfer Matrix Method (TMM) algorithm. As a superlattice environment in the simulation the water was used. The material used to construct the structure was a PNM-0.38PT piezoelectric. Multilayer types have been selected so that the total number of layers for a given generation is equal in all structures.

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Deymier, Pierre A., Keith Runge, Alexander Khanikaev, and Andrea Alù. "Pseudo-Spin Polarized One-Way Elastic Wave Eigenstates in One-Dimensional Phononic Superlattices." Crystals 14, no. 1 (January 19, 2024): 92. http://dx.doi.org/10.3390/cryst14010092.

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We investigate a one-dimensional discrete binary elastic superlattice bridging continuous models of superlattices that showcase a one-way propagation character, as well as the discrete elastic Su–Schrieffer–Heeger model, which does not exhibit this character. By considering Bloch wave solutions of the superlattice wave equation, we demonstrate conditions supporting elastic eigenmodes that do not satisfy the translational invariance of Bloch waves over the entire Brillouin zone, unless their amplitude vanishes for a certain wave number. These modes are characterized by a pseudo-spin and occur only on one side of the Brillouin zone for a given spin, leading to spin-selective one-way wave propagation. We demonstrate how these features result from the interplay of the translational invariance of Bloch waves, pseudo-spins, and a Fabry–Pérot resonance condition in the superlattice unit cell.

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Reinhart, Wesley F., and Athanassios Z. Panagiotopoulos. "Multi-atom pattern analysis for binary superlattices." Soft Matter 13, no. 38 (2017): 6803–9. http://dx.doi.org/10.1039/c7sm01642e.

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Caid, M., H. Rached, D. Rached, R. Khenata, S. Bin Omran, D. Vashney, B. Abidri, N. Benkhettou, A. Chahed, and O. Benhellal. "Electronic structure and optical properties of (BeTe)n/(ZnSe)m superlattices." Materials Science-Poland 34, no. 1 (March 1, 2016): 115–25. http://dx.doi.org/10.1515/msp-2016-0004.

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AbstractThe structural, electronic and optical properties of (BeTe)n/(ZnSe)m superlattices have been computationally evaluated for different conﬁgurations with m = n and m≠n using the full-potential linear mufﬁn-tin method. The exchange and correlation potentials are treated by the local density approximation (LDA). The ground state properties of (BeTe)n/(ZnSe)m binary compounds are determined and compared with the available data. It is found that the superlattice band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(ω), the refractive index n(ω) and the refractivity R(ω), are calculated for radiation energies up to 35 eV.

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Mao, Runfang, Evan Pretti, and Jeetain Mittal. "Temperature-Controlled Reconfigurable Nanoparticle Binary Superlattices." ACS Nano 15, no. 5 (May 3, 2021): 8466–73. http://dx.doi.org/10.1021/acsnano.0c10874.

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Zha, Xun, and Alex Travesset. "Thermodynamic Equilibrium of Binary Nanocrystal Superlattices." Journal of Physical Chemistry C 125, no. 34 (August 18, 2021): 18936–45. http://dx.doi.org/10.1021/acs.jpcc.1c05015.

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Tkachenko, Alexei V. "Generic phase diagram of binary superlattices." Proceedings of the National Academy of Sciences 113, no. 37 (August 26, 2016): 10269–74. http://dx.doi.org/10.1073/pnas.1525358113.

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Emergence of a large variety of self-assembled superlattices is a dramatic recent trend in the fields of nanoparticle and colloidal sciences. Motivated by this development, we propose a model that combines simplicity with a remarkably rich phase behavior applicable to a wide range of such self-assembled systems. Those systems include nanoparticle and colloidal assemblies driven by DNA-mediated interactions, electrostatics, and possibly, controlled drying. In our model, a binary system of large and small hard spheres (L and S, respectively) interacts via selective short-range (“sticky”) attraction. In its simplest version, this binary sticky sphere model features attraction only between S and L particles. We show that, in the limit when this attraction is sufficiently strong compared with kT, the problem becomes purely geometrical: the thermodynamically preferred state should maximize the number of LS contacts. A general procedure for constructing the phase diagram as a function of system composition f and particle size ratio r is outlined. In this way, the global phase behavior can be calculated very efficiently for a given set of plausible candidate phases. Furthermore, the geometric nature of the problem enables us to generate those candidate phases through a well-defined and intuitive construction. We calculate the phase diagrams for both 2D and 3D systems and compare the results with existing experiments. Most of the 3D superlattices observed to date are featured in our phase diagram, whereas several more are predicted for future discovery.

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Shevchenko, Elena V., Dmitri V. Talapin, Nicholas A. Kotov, Stephen O'Brien, and Christopher B. Murray. "Structural diversity in binary nanoparticle superlattices." Nature 439, no. 7072 (January 2006): 55–59. http://dx.doi.org/10.1038/nature04414.

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Overgaag, Karin, Wiel Evers, Bart de Nijs, Rolf Koole, Johannes Meeldijk, and Daniel Vanmaekelbergh. "Binary Superlattices of PbSe and CdSe Nanocrystals." Journal of the American Chemical Society 130, no. 25 (June 2008): 7833–35. http://dx.doi.org/10.1021/ja802932m.

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Більше джерел

Дисертації з теми "Binary superlattices"

Huang, Xuren. "Linear, Nonlinear Optical and Transport Properties of Quantum Wells Composed of Short Period Strained InAs/GaAs Superlattices." Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc278855/.

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In this work, ordered all-binary short-period strained InAs/GaAs superlattice quantum wells were studied as an alternative to strained ternary alloy InGaAs/GaAs quantum wells. InGaAs quantum wells QWs have been of great interest in recent years due to the great potential applications of these materials in future generations of electronic and optoelectronic devices. The all binary structures are expected to have all the advantages of their ternary counterparts, plus several additional benefits related to growth, to the elimination of alloy disorder scattering and to the presence of a higher average indium content.

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Neves, Herbert Rodrigo. "Síntese e estudo da auto-organização de membranas de superredes binárias baseadas em nanopartículas de ferritas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/75/75134/tde-16032018-094329/.

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O estudo do ordenamento de nanopartículas em estruturas bi e tridimensionais, também conhecidas como superredes, é de grande interesse científico e tecnológico, tanto pelo interesse em se explicar a origem e as consequências deste fenômeno, quanto pelas possibilidades de aplicação oriundas das propriedades observadas nestes sistemas. Quando são utilizados dois tipos de nanomateriais diferentes em tamanho e/ou composição química, tem-se a formação de superredes binárias. Estas estruturas apresentam propriedades que são resultado das propriedades individuais de seus constituintes e, além disso, do conjunto de interações que existem no sistema. Graças a este conjunto de propriedades e interações coletivas, o princípio de se empregar nanopartículas como \"building blocks\" para a criação ou aprimoramento de dispositivos funcionais. Assim, neste trabalho são discutidas as sínteses de óxidos magnéticos do tipo MFe2O4 (com M = Co, Fe ou Mn) e as características necessárias para o emprego destes na formação de superredes de nanopartículas. Os materiais foram sintetizados procurando-se alcançar uma estreita distribuição de tamanho e homogeneidade quanto à forma. Foram empregados sistemas de nanopartículas nos estudos para a formação de superredes que apresentaram polidispersividade entre 6 e 20%, de forma a discutir o efeito desta propriedade no ordenamento das nanopartículas. Observou-se que o ordenamento em escala macroscópica é fortemente influenciado pela tensão de superfície da subfase, enquanto que o arranjo local das nanopartículas em relação aos seus vizinhos mais próximos é mais influenciado pela taxa de evaporação do solvente e pelas interações interpartículas. Para a formação de superestruturas binárias foram empregadas as nanopartículas de CoO/CoFe2O4 com 9,6 nm ou de Fe3O4 de 10,7 nm, com nanopartículas de CdSe de 3,6 nm. Os sistemas de nanopartículas binárias apresentaram arranjos do tipo AlB2 e tiveram, em sua maioria, crescimento na forma de supercristais facetados. A formação de estruturas bidimensionais com crescimento ao longo do plano da membrana foi favorecida pelo aumento na proporção das nanopartículas de maior diâmetro em relação às menores. A compreensão do fenômeno de auto-organização em membranas de superredes binárias possibilita a obtenção de novos materiais nanoestruturados e que apresentem propriedades moduladas.
Self-assembly nanoparticles into superlattices array have attracted significant attention both for the scientific understanding of nanocrystals ordering process and the development of new functional devices using bottom up techniques. The co-assembly of two types of nanoparticles in binary nanoparticles superlattices provides a new way to design metamaterials with unusual and modulated properties. These unusual properties arise from interparticle interactions in the superlattice structure, and from nanoparticles physical properties. To obtain highly ordered structures, it is required that nanocrystals have narrow size distribution. This thesis presents the synthesis of oxide magnetic nanoparticles (MFe2O4; M = Co, Fe, or Mn) and their application as building blocks in nanocrystal superlattices. Nanoparticles presented size distribution from 6% to 20%, and their assemblies has shown amorphous structure when samples have size distribution above 10%. Self-assembled nanoparticles superlattices in the liquid-air interface were obtained using either single or binary components. Single component superlattices were used as model for the understand of self-assembly process, which depends on subphase surface tension and dispersion evaporation rate. Nanocrystals superlattices were obtained from CdSe nanoparticles, with average size of 3,6 nm, and CoO/CoFe2O4 with size of 9,6 nm, and was observed a AlB2-type superstructure. The same superlattice structure was obtained for CdSe and Fe3O4, with average size of 10,7 nm, which indicate that AlB2 is the equilibrium phase for a rage of radii ratios and nanoparticles stoichiometry. These findings enable to better understand self-assembled binary nanocrystal superlattices formation and how to manipulate interparticle interactions in order to synthesize highly ordered structures.

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Lee, Suyeon. "Synthesis and properties of mono and bi- metallic nanoparticles of noble metals; towards fabrication of novel functional nanoparticles assemblies." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS580.

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Les nanoparticules de métaux nobles ont suscité un grand intérêt ces dernières années dans divers domaines en raison de leurs propriétés physiques et chimiques distinctes telles que les propriétés optiques, catalytiques ou magnétiques. Dans cette thèse, nous avons étudié les différentes approches permettant d'intégrer deux métaux dans un même système, comme les nanoparticules bimétalliques, ou les super-réseaux binaires pour obtenir de nouvelles propriétés. Nous avons mis au point une méthode de croissance à partir de graines pour synthétiser de manière rationnelle des nanoparticules cœur-coquille Au(ou Ag)@M (M=Ag, Pd, Pt). L'impact des paramètres de synthèse tels que la concentration des précurseurs métalliques, la nature des ligands ou la température sur les paramètres clés des nanoparticules (taille du noyau, épaisseur de la coque, dispersion) a été étudié. Les propriétés optiques, vibratoires et catalytiques des différentes nanoparticules bimétalliques ont été caractérisées en fonction de leur structure, de leur composition chimique, du nombre de couches atomiques de la couche et de la cristallinité du noyau. En outre, des super-réseaux binaires de NP, qui sont co-assemblés à partir de deux composants complémentaires différents, ont également été signalés. Plusieurs conditions d'assemblage (rapport de taille effective, rapport de concentration, température de dépôt, méthode de dépôt) ont été explorées. Le mécanisme physique responsable de la variation structurelle observée a ainsi été identifié. Une variété de structures cristallines pour les super-réseaux binaires telles que AlB2, NaZn13, NaCl ont été produites. Enfin, les propriétés magnétiques des super-réseaux binaires de nanoparticules Fe2O3/Au ont été étudiées. Elles sont déterminées par la distance interparticulaire des nanoparticules Fe2O3 modulée par l'insertion des nanoparticules Au
Noble metal nanoparticles (NPs) have attracted a great interest last years in various domains due to their distinct physical and chemical properties such as optical, catalytic or magnetic properties. In this thesis, we investigated the various approaches to integrate two metals in the same system, such as bimetallic nanoparticles, or binary superlattices to obtain new properties. We have developed seed-mediated growth method to rationally synthesis core-shell NPs Au(or Ag)@M (M=Ag, Pd, Pt). The impact of synthesis parameters such as concentration of metallic precursors, nature of ligands or temperature on key NPs parameters (core size, shell thickness, dispersity) was studied. The optical, vibrational and catalytic properties of different bimetallic NPs were characterized according to their structure, chemical composition, number of shell atomic layer and core crystallinities. In addition, binary NP superlattices, which are co-assembled from of two different complementary components were also reported. Several assembly conditions (effective size ratio, concentration ratio, deposition temperature, deposition method) were explored. The physical mechanism responsible for the observed structural variation was thus identified. A variety of crystalline structures for the binary superlattices such as AlB2, NaZn13, NaCl were produced. Finally, the magnetic properties of Fe2O3/Au NP binary superlattices were studied. They are determined by the interparticle distance of Fe2O3 NPs modulated by the insertion of Au NPs

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Barbara, Dechelette Aude. "Caractérisation structurale et magnétique de superréseaux métaux de transition/Ir par diffraction des rayons X." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10169.

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Il est depuis longtemps admis que la structure et le magnetisme des metaux de transition 3d sont fortement correles, tant dans leurs phases massiques qu'en structures epitaxiees. Afin d'etre en mesure de relier les proprietes structurales et magnetiques d'un superreseau magnetique, il est donc necessaire de caracteriser finement sa structure. La diffraction symetrique des plans paralleles a la surface, associee a l'exploitation de l'effet anomal, la diffraction en incidence et emergence rasantes et la diffraction le long de tiges h#0k#0 de l'espace reciproque, sensible a l'arrangement atomique dans le plan et hors du plan des couches, ont ete utilisees pour caracteriser la structure des deux sous-reseaux des superreseaux. Nous avons ainsi mene l'etude de superreseaux fe#xmn#1#-#x/ir(001) pour deux concentrations x = 0,7 et x = 0,9. Ces concentrations sont choisies autour de la valeur x = 0,75 qui provient d'une etude preliminaires menees sur des monofilms d'alliages fe#xmn#1#-#x relaxes, ayant mis en evidence une transition structurale d'un comportement proche du fe cc (x> 0,75) a un comportement proche du mn cfc (x< 0,75). Une phase unique dans l'echantillon x = 0,7 et deux phases dans l'echantillon x = 0,9, l'une contrainte et l'autre relaxee, ont ete observees. De plus, le controle de la profondeur d'analyse, effectue en variant l'angle d'incidence maintenu rasant, permet de proposer une image de la repartition des deux phases dans l'echantillon x = 0,9. Enfin, les proprietes magnetiques, mesurees par diffraction magnetique resonante des rayons x, indiquent un comportement ferromagnetique bas spin (x = 0,7) et haut spin (x = 0,9) avec des moments respectifs de 0,2 #b/at et 2 #b/at. La synthese des investigations structurales et magnetiques fait ressortir l'importance du rapport de tetragonalisation c/a des differentes phases d'alliage femn qui diminue en fonction de la stoechiometrie et qui semble etre a l'origine de la transition magnetique observee.

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BOUCHET-BOUDET, NATHALIE. "Etude par diffraction de rayons x d'heterostructures epitaxiees a base des semi-conducteurs ii-vi cdte et znte." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10153.

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Ce memoire traite de la caracterisation structurale par diffraction et reflectivite de rayons x d'heterostructures de semi-conducteurs ii-vi cdte et znte. Ce sont des heterostructures a fort desaccord parametrique, elaborees par epitaxie par jets moleculaires. Ce travail s'articule autour de deux themes: la caracterisation de reseaux de fils quantiques de znte, elabores par croissance par avancee de marche sur une surface vicinale de cdte (001), et l'etude des correlations verticales dans des superreseaux cd#0#. #8zn#0#. #2te/cdte et des superreseaux d'insertions fractionnaires de znte dans cdte. La croissance de systemes organises est un sujet tres actuel ; on espere ainsi elaborer des superreseaux de boites quantiques dans lesquelles les boites (ou les fils) presentent non seulement un ordre lateral, mais aussi un ordre vertical. L'insertion d'un plan fractionnaire de znte dans une matrice de cdte peut etre detectee en reflectivite de rayons x. La deformation parallele a l'axe de croissance, induite par le znte, est deduite du traitement de la reflectivite par un modele cinematique. La mesure de la periodicite laterale des fils deposes sur une surface vicinale est un sujet nouveau et tres delicat. Des mesures effectuees sur un echantillon desoriente de 1 et contenant un superreseau vertical ont donne la preuve de l'existence d'une periode laterale. Les longueurs de correlation dans le plan et hors du plan d'un superreseau de 2 couches de cd#0#. #8zn#0#. #2te et cdte de meme epaisseur sont deduites des mesures d'intensite diffuse en incidence rasante. Les calculs d'intensite diffuse sont faits dans l'approximation de born dite d'onde distordue. On montre enfin que des correlations verticales existent dans des superreseaux de boites et qu'il est possible de les mesurer en diffraction autour des pics de bragg. La correlation verticale est deux fois plus etendue dans un echantillon vicinal que dans un echantillon nominal

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Charleux, Marion. "Étude par microscopie électronique d'hétérostructures de semiconducteurs II-VI élaborés par épitaxie par jets moléculaires alternés : vers la réalisation de fils quantiques." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0045.

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Cette these est une etude par microscopie electronique en transmission (met) d'heterostructures de semiconducteurs ii-vi. Les systemes etudies, cdte/mnte et cdte/mgte, ont ete realises par epitaxie par jets moleculaires (ejm) et par epitaxie par jets moleculaires alternes (ejma). Le but de ce travail est de contribuer a la fabrication de structures quantiques unidimensionnelles ou fils quantiques : les resultats presentes dans ce memoire sont une premiere pour ces materiaux, bien qu'ils restent neanmoins encore loin de la perfection. En vue d'une optimisation des conditions de croissance, nous evaluons par met haute resolution la qualite cristalline des interfaces - en termes de profils chimiques et rugosite - dans des multicouches obtenues a 280c pour differentes conditions d'epitaxie. Deux methodes d'analyse d'image ont ete abordees : (i) la mesure des distorsions locales du reseau atomique pour cdte/mnte et (ii) l'analyse des contrastes de motif hr pour cdte/mgte. Cette etude montre la legere superiorite de l'ejma optimisee par rapport a l'ejm standard, en matiere de controle de l'epaisseur et de la regularite des depots ainsi qu'au niveau de la qualite des interfaces obtenues. L'ejma dans les conditions optimales, nous a permis de realiser des superreseaux lateraux (srl) cdte/mnte par croissance organisee sur une surface a marches ou surface vicinale (001). Les cliches de met en mode deux ondes (002) obtenus donnent cependant une demixtion laterale en element ii (cd, mn) qui est en fait dix fois inferieure a celle idealement attendue. Nous expliquons cette dilution mesuree par une forte rugosite des brods de marches qui conduirait a une dilution apparente des srl en raison de la projection dans l'epaisseur de l'image de microscopie.

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Widmann, Frédéric. "Epitaxie par jets moléculaires de GaN, AlN, InN et leurs alliages : physique de la croissance et réalisation de nanostructures." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10234.

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Ce travail a porte sur la croissance epitaxiale des nitrures d'elements iii gan, aln, et inn, en utilisant l'epitaxie par jets moleculaires assistee par plasma d'azote. Nous avons optimise les premiers stades de la croissance de gan ou aln sur substrat al#2o#3 (0001). Le processus utilise consiste a nitrurer la surface du substrat a l'aide du plasma d'azote, afin de la transformer en aln, puis a faire croitre une couche tampon d'aln ou de gan a basse temperature, avant de reprendre la croissance de gan ou aln a haute temperature (680 a 750c). Nous avons en particulier etudie les proprietes d'une couche de gan en fonction de la temperature a laquelle est realisee l'etape de nitruration. Lorsque les conditions de demarrage de la croissance sont optimisees, nous avons pu observer des oscillations de rheed pendant la croissance de la couche de gan. Nous avons etudie l'effet du rapport v/iii sur la morphologie de surface et les proprietes optiques et structurales de cette couche. Nous avons propose l'utilisation de l'indium en tant que surfactant pour ameliorer ces proprietes. Nous avons ensuite aborde la realisation de superreseaux gan/aln dont nous avons optimise les interfaces. Les mecanismes de relaxation des contraintes de aln sur gan et gan sur aln ont ete etudies. Nous avons egalement elabore les alliages algan et ingan, comme barrieres quantiques dans les heterostructures. Nous avons montre que la relaxation elastique des contraintes de gan en epitaxie sur aln donne lieu a la formation d'ilots de tailles nanometriques, qui se comportent comme des boites quantiques. Leur densite et leur taille dependent de la temperature de croissance, et des conditions de murissement apres croissance. Les proprietes optiques de ces ilots sont gouvernees a la fois par les effets de confinement quantique et par le fort champ piezo-electrique induit par la contrainte dans les ilots.

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Hartmann, Jean-Michel. "Epitaxie par jets moléculaires alternés d'hétérostructures CdTe/Mn(Mg)Te : application à la réalisation de super-réseaux verticaux." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10204.

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Le but de ce travail est de developper des methodes de croissance pour fabriquer in-situ des nanostructures - en particulier des reseaux de fils quantiques - a base de semiconducteurs ii-vi de la famille des tellurures. Pour ce faire, nous avons fait appel a l'epitaxie par jets moleculaires alternes (envoi alterne des elements ii et des elements vi), technique permet un controle ultime des phenomenes d'incorporation des atomes en surface. Nous avons obtenu pour cdte deux regimes d'autoregulation, le premier a 0. 5 monocouches (mc) de cdte deposees par cycle d'ejma entre 260c et 290c, le second a 1 mc/cycle entre 230c et 240c. Pour mgte, un regime d'autoregulation a 0. 7mc/cycle d'ejma a ete mis en evidence entre 260c et 300c. Pour mnte, par contre, tous les atomes de mn incidents s'incorporent a 280c. Une etude systematique de super-reseaux cdte/mnte et cdte/mgte nous a permis d'une part d'evaluer et d'optimiser la morphologie des interfaces, d'autre part d'avoir acces a des parametres physiques importants de mgte (parametre de maille 6. 42 a, energie de bande interdite a l'ambiante 3. 5 ev, rapport des constantes elastiques 2c#1#2/#c#1#1=1. 06) comme de mnte (2c#1#2/#c#1#1=1. 12). En particulier, un modele de segregation a ete utilise pour decrire quantitativement les interfaces directes et inverses des super-reseaux cdte/mnte. Enfin, nous avons obtenu en croissance par avancees de marches sur surfaces vicinales des super-reseaux inclines (sri) cdte/mnte. Une grande regularite de la periode et de l'angle d'inclinaison de ces sri a ete demontree, avec une modulation laterale de la composition en mn de l'ordre de10%. Ce potentiel lateral de confinement a ete mis en evidence en optique a l'aide de mesures d'anisotropie de la polarisation.

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Tardot, Alain. "Diffraction de rayons X et interdiffusion dans les superréseaux CdTe/CdZnTe et CdTe/HgTe." Grenoble 1, 1993. http://www.theses.fr/1993GRE10090.

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Ce travail concerne la caracterisation structurale et l'etude de l'interdiffusion dans les superreseaux contraints cdte/cdznte et cdte/hgte, elabores par epitaxie par jets moleculaires, au moyen de la double diffraction de rayons x. Les parametres structuraux (composition, epaisseur, etat de deformation) sont obtenus de facon precise en utilisant conjointement l'experience et la simulation en theorie cinematique. Les coefficients d'interdiffusion des couples cd/zn (400c) et cd/hg (200c) sont mesures par diffraction x. Ils permettent de calculer les profils de concentration des superreseaux en fonction de la temperature et du temps de recuit. Par extrapolation, nous precisons les conditions de croissance pour obtenir des interfaces raides, qui sont necessaires pour des dispositifs optoelectroniques performants

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Sharma, Siddharth. "Phase Behaviour of Oppositely Charged Nanoparticles : A Study of Binary Nanoparticle Superlattices." Thesis, 2011. https://etd.iisc.ac.in/handle/2005/4603.

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Binary nanoparticle superlattices or BNSL’s have been a major area of research in nanotechnology for the last decade. The conventional lithographic techniques are limited to fabricate features only within a plane while these self-assembled structures are formed within a given volume. The potential applications of self-assembly leading to crystalline structures include nanoelectronics, photonics and improving the fundamental understanding of the bottom-up approach as well. The present work deals with the crystallization of nanoparticles in a colloidal suspension leading to three dimensional crystals(BNSL’s). The goal is to generate phase diagrams for binary nanoparticle suspensions with varying charge ratios between the two particles. Monte Carlo molecular simulations in various equilibrium ensembles are the basis for the generation of equations of state and calculation of free energies of the two coexisting phases. Coexistence here implies the solid-fluid thermodynamic equilibrium and consequently the equivalence of free energies. The calculation framework is standard for pure substances, but advanced techniques need to be used for mixtures. The focal point of this work is the effect of charge asymmetry on the formation and stability of BNSL’s from the binary suspension. There are six phase diagrams for charge ratios of 0, 􀀀0:2, 􀀀0:4, 􀀀0:6, 􀀀0:8 and 􀀀1:0. The variables are the reduced pressure P_ and the mole fraction XA. The proposed applications of BNSL’s are generally dependent on substitutional order. From the results, symmetric mixtures are favorable for the formation of BNSL’s while charge asymmetry gives rise to solid solutions.

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Частини книг з теми "Binary superlattices"

LIN, CHIA-CHIAO. "ON THE DEPENDENCE OF INTERACTION ENERGY UPON ATOMIC ARRANGEMENTS IN SUPERLATTICE.S OF BINARY ALLOYS." In Selected Papers of C C Lin with Commentary, 361–76. WORLD SCIENTIFIC, 1987. http://dx.doi.org/10.1142/9789814415651_0024.

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Тези доповідей конференцій з теми "Binary superlattices"

Raino, Gabriele. "Superfluorescence from Binary Perovskite Superlattices." In nanoGe Spring Meeting 2022. València: Fundació Scito, 2022. http://dx.doi.org/10.29363/nanoge.nsm.2022.059.

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Heinrich, Matthias, Yarsolav V. Kartashov, Lourdes P. Ramirez, Alexander Szameit, Felix Dreisow, Robert Keil, Stefan Nolte, Andreas Tünnermann, Victor A. Vysloukh, and Lluis Torner. "Solitons in Two-Dimensional Binary Superlattices." In Quantum Electronics and Laser Science Conference. Washington, D.C.: OSA, 2010. http://dx.doi.org/10.1364/qels.2010.qtuc5.

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Zhao, Zhouzhou, and Wei Lu. "Growing Large Nanostructured Superlattices by Sequential Activation of Self-Assembly." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63589.

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We propose a mechanism to grow a large superlattice of phase domains from a continuum homogenous binary film by sequential activation of self-assembly. Self-assembly was initiated in a small mobile region, where atoms could diffuse, to form a seed pattern, Then the mobile region was shifted gradually. This process led to the formation of a long-rang ordered superlattice, regardless whether the seed was perfect or not. The pattern quickly improved to a perfect superlattice along with the sequential activation. We found that the scanning velocity can effectively control the domain pattern when the system is in a bistable state, which refers to a window of average concentration where two different superlattices can both stabilize. We demonstrated two schemes for large-scale high speed fabrication: alternation between scanning directions, using the superlattice created in each previous step as a large seed; and two dimensional growth.

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Landry, E. S., A. J. H. McGaughey, and M. I. Hussein. "Superlattice Analysis for Tailored Thermal Transport Characteristics." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13673.

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Molecular dynamics simulations and the Green-Kubo method are used to predict the thermal conductivity of binary Lennard-Jones superlattices and alloys. The superlattice thermal conductivity trends are in agreement with those obtained through the direct method, verifying that the Green-Kubo method can be used to examine thermal transport in heterostructures. The simulation temperature and the constituent species are fixed while the superlattice period structure is varied with the goals of (i) minimizing the cross-plane thermal conductivity and (ii) maximizing the ratio of in-plane to cross-plane thermal conductivities. The superlattice thermal conductivity in both the cross-plane and in-plane directions is found to be greater than the corresponding alloy value and less than the value predicted from continuum theory. The anisotropy of the thermal conductivity tensor is found to be at a maximum for a superlattice with a uniform layer thickness. Lattice dynamics calculations are used to investigate the role of optical phonons in the thermal transport.

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Marino, Emanuele, Christopher B. Murray, Timothy C. Moore, Sjoerd W. van Dongen, Austin W. Keller, Di An, Shengsong Yang, et al. "Unraveling the Self-Assembly Pathway of Binary Nanocrystal Superlattices." In nanoGe Spring Meeting 2022. València: Fundació Scito, 2022. http://dx.doi.org/10.29363/nanoge.nsm.2022.334.

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Panoiu, Nicolae C., Richard M. Osgood, Shuang Zhang, and Steven R. J. Brueck. "Zero-n Photonic Band-Gaps in Binary Photonic Crystal Superlattices." In Integrated Photonics Research and Applications. Washington, D.C.: OSA, 2006. http://dx.doi.org/10.1364/ipra.2006.iwb2.

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Manoli, Andreas, Grigorios Itskos, Marios Sergides, Taras Sekh, Etsuki Kobiyama, Modestos Athanasiou, Maryna I. Bodnarchuk, et al. "Optical Properties of Binary Nanocrystal Superlattices Produced by Assemblies of Strongly and Weakly Confined CsPbBr3 Perovskite Nanocrystals." In International Conference on Emerging Light Emitting Materials 2023. València: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2023. http://dx.doi.org/10.29363/nanoge.emlem.2023.029.

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YOSHIDA, Junji, Ichirou NOMURA, Akihiko KIKUCHI, and Katsumi KISHINO. "Substrate Misorientation Effect on Self-Organization of Quantum-Wires in (GaP)m/(InP)m Short Period Binary Superlattices." In 1995 International Conference on Solid State Devices and Materials. The Japan Society of Applied Physics, 1995. http://dx.doi.org/10.7567/ssdm.1995.s-vi-7.

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McCallum, D. S., X. R. Huang, Martin D. Dawson, Thomas F. Boggess, Arthur L. Smirl, T. C. Hasenberg, and Alan Kost. "Nonlinearities and ultrafast charge transport in an all-binary strained InAs/GaAs hetero n-i-p-i." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.mff1.

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We use differential spectroscopy with tunable psec pulses to temporally and spectrally resolve the formation and decay of optical nonlinearities and space-charge fields in a hetero n-i-p-i that contains quantum wells in the intrinsic region composed of all-binary InAs/GaAs short-period strained layer superlattices. The evolution of the resulting nonlinearity is determined by a delicate competition between excitonic bleaching and the excitonic shift caused by a screening of the builtin field. The relative contributions of the two nonlinearities are complicated functions of fluence, time and wavelength, with the detailed dynamics determined by thermionic emission from the wells, psec charge transport over nm dimensions, screening, and carrier recombinations. The distinctive spectral signatures for excitonic bleaching and shifting allow us to distinguish the two contributions to the nonlinear dynamics and to follow the charge transport and space-charge formation. At the lower fluences, the initial excitonic bleaching gives way to a blue shift of the exciton as the carriers escape the wells in ~3 psec and drift to screen the built-in field in <10 psec. This blue shift persists until the spatially separated carriers recombine nonexponentially on microsecond time scales. At higher fluences, excitonic bleaching and the blue shift are observed simultaneously, since only a fraction of the carriers are required to screen the field and the wells remain partially occupied. On the time scale of ~10 nsec, the bleaching contribution disappears as the carriers within the wells recombine, leaving only the persistent blue shift.

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Hoffman, Darin, and Manijeh Razeghi. "Positive and negative luminescence in binary type II InAs/GaSb superlattice photodiodes." In Integrated Optoelectronic Devices 2006, edited by Manijeh Razeghi and Gail J. Brown. SPIE, 2006. http://dx.doi.org/10.1117/12.659118.

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