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Leimkühler, Gisbert. "Elektrochemische Herstellung und strukturelle Untersuchung von Sb2Te3 und SbxTey." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969279493.
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Yu, Bo. "Fabrication and Evaluation of Sb2Te3/PVDF Hybrid Thermoelectric Films." Thesis, KTH, Tillämpad fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288684.
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Thermoelectric (TE) materials and devices have been extensively studied for harvesting waste heat energy. There is more interest to fabricate TE materials and devices at low cost and highly-efficient ways. Besides, TE materials and devices should be flexible and light-weight to address the requirements of emerging applications such as wearable TE power generators, health sensors, and powering small mobile wireless devices. To fabricate flexible and light-weight TE films with low cost and high-efficiency, organic- inorganic hybrid materials have been introduced. Organic-inorganic hybrid materials not only show the advantages of organic materials, such as good flexibility, light-weight, low cost, but also reflects the good TE properties of inorganic TE materials. The aim of this project was to synthesize and investigate the p-type hybrid TE films.Recently, many different methods and mechanisms have been tested to improve TE performance of materials. One of these mechanisms called defect engineering, which has been used to enhance TE performance by increasing the carrier concentration. Another approach can be the introduction of interfaces and grain boundaries which can improve TE performance by suppressing lattice thermal conductivity. In addition, nanomaterials and low-dimensional materials are also used for improving TE performance, classical size effect suppresses lattice thermal conductivity by limiting the mean free path, while quantum size effect increases the Seebeck coefficient by creating a clear electronic density of state function.In this project, flexible and free-standing TE films based on Sb2Te3 nanoplatelets/PVDF composites have been fabricated via doctor blading method. The SEM images of these films show that they are porous structures. The sizes of Sb2Te3 nanoplates are around 1 μm with hexagonal morphology. Porous and nano-sized structures are helpful for enhancing ZT of TE films. However, porous structures not only reduce thermal conductivity but also deteriorate electrical conductivity. The resistance results of the films with different ratio of Sb2Te3/PVDF showed that the existence of porous structures in the films deteriorates the $ of films, which is seen in samples with low PVDF content. Initial findings are promising and can pave the way to design TE-paste to generate active surfaces with easily applicable hybrid materials.Termoelektriska (TE) material och anordningar har studerats för att skörda spillvärmeenergi. Det är mer intresse att tillverka TE-material och enheter till låga kostnader och på ett högeffektivt sätt. TE-material och enheter bör dessutom vara flexibla och lätta att bämöta krav på nya applikationer som bärbara TE-kraftgeneratorer, hälsosensorer och driva små mobila trådlösa enheter. För att tillverka flexibla och lätta TE-filmer med ett billigt och högeffektivt sätt har organiska-oorganiska hybridmaterial införts. Organiska-oorganiska hybridmaterial visar inte bara fördelarna med organiska material, såsom god flexibilitet, lätt vikt, låg kostnad, utan återspeglar också de goda TE egenskaperna hos oorganiska TE material. Syftet med detta projekt var att syntetisera och undersöka p-typ hybrid-TE-filmer.Nyligen uppståd många metoder och mekanismer för att förbättra TE prestanda. Den första är defektteknik, vilket ökar bärarkoncentrationen för att förbättra TE prestanda. Dessutom kan införandet av gränssnitt och korngräns förbättra TE prestanda genom att undertrycka gitterens värmeledningsförmåga. Dessutom används nanomaterial och material med låg dimension också för att förbättra TE prestanda, klassisk storlekseffekt undertrycker gitterens värmeledningsförmåga genom att begränsa den genomsnittliga fria vägen, medan kvantstorlekseffekt ökar Seebeck-koefficienten genom att skapa en tydlig elektronisk tillståndstäthet (DOS) fungera.I detta projekt, mycket flexibla och fristående termoelektriska filmtyger baserade på Sb2Te3-nanoplater / PVDF-kompositer med doktorblåsningsmetod. SEM-bilderna av dessa filmer visar att de är porösa strukturer. Och det framgår tydligt att morfologin hos Sb2Te3-nanoplater är cirka 1 μm hexagonala strukturer. Teoretiskt är porösa strukturer och nanostrukturer användbara för att förbättra ZT av TE-filmer. Porösa strukturer minskar emellertid inte bara värmeledningsförmågan utan försämrar även den elektriska konduktiviteten. Resistensresultaten för filmerna med olika Sb2Te3/PVDF förhållanden visade att förekomsten av porösa strukturer i filmerna försämrar filmens elektriska konduktivitet, vilket ses i prover med lågt PVDF-innehåll. Preliminära resultat är lovande och kan bana väg för att designa en tjock TE-lösning för att generera aktiva ytor med lätt tillämpliga hybridmaterial.
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Wang, Rui Ning. "Epitaxial growth and characterization of GeTe and GeTe/Sb2Te3 superlattices." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18135.
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Die epitaktische Wachstum von GeTe Dünnschichten und Sb2Te3/GeTe Übergittern durch Molekularstrahlepitaxie wird auf drei verschiedenen Silizium Oberflächen gezeigt: Si(111)−(7×7), Si(111)−(√3×√3)R30°−Sb, und Si(111)−(1×1)−H. Mit Röntgenstrukturanalyse wird bewiesen, dass die epitaktische Beziehung der GeTe Schicht von der Oberflächepassievierung abhängig ist; auf einer passivierten Fläche können verdrehte Domänen unterdrückt sein. Dieses Verhalten ähnelt dem, welches bei 2D Materialien zu erwarten wäre, und wird auf die Schwäche der Resonanten ungebundenen Zustände zurückgeführt, die durch Peierls Verzerrung noch schwächer werden.The growth by molecular beam epitaxy of GeTe and Sb2Te3/GeTe superlattices on three differently reconstructed Si(111) surfaces is demonstrated. Namely, these are the Si(111)−(7×7), Si(111)−(√3×√3)R30°−Sb, and Si(111)−(1×1)−H reconstructions. Through X-ray diffraction, the epitaxial relationship of GeTe is shown to depend on the passivation of the surface; in-plane twisted and twinned domains could be suppressed on a passivated surface. This behavior which resembles what would be expected from lamellar materials, is attributed to the relative weakness of resonant dangling bonds, that are further weakened by Peierls distortion.
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Wolf, Michael Scott. "Infrared and Optical Studies of Topological Insulators BI2TE3 BI2SE3 and SB2TE3." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1310675743.
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Bragaglia, Valeria. "Epitaxial Growth and Ultrafast Dynamics of GeSbTe Alloys and GeTe/Sb2Te3 Superlattices." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18406.
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In dieser Arbeit wird das Wachstum von dünnen quasi-kristallinen Ge-Sb-Te (GST) Schichten mittels Molekularstrahlepitaxie demonstriert, die zu einer geordneten Konfiguration von intrinsischen Kristallgitterfehlstellen führen. Es wird gezeigt, wie es eine Strukturanalyse basierend auf Röntgenstrahlbeugungssimulationen, Dichtefunktionaltheorie und Transmissionselektronenmikroskopie ermöglicht, eine eindeutige Beurteilung der Kristallgitterlückenanordnung in den GST-Proben vorzunehmen. Das Verständnis für die Ordnungsprozesse der Gitterfehlstellen erlaubt eine gezielte Einstellung des Ordnungsgrades selbst, der mit der Zusammensetzung und der Kristallphase des Materials in Zusammenhang steht. Auf dieser Basis wurde ein Phasendiagramm mit verschiedenen Wachstumsfenstern für GST erstellt. Des Weiteren wird gezeigt, dass man eine hohe Ordnung der Gitterfehlstellen in GST auch durch Ausheizprozesse und anhand von Femtosekunden-gepulster Laserkristallisation von amorphem Material erhält, das zuvor auf einem als Kristallisationsgrundlage dienenden Substrat abgeschiedenen wurde. Diese Erkenntnis ist bemerkenswert, da sie zeigt, dass sich kristalline GST Schichten mit geordneten Kristallgitterlücken durch verschiedene Herstellungsprozesse realisieren lassen. Darüber hinaus wurde das Wachstum von GeTe/Sb2Te3 Übergittern durchgeführt, deren Struktur die von GST mit geordneten Gitterfehlstellen widerspiegelt.
Die Möglichkeit den Grad der Gitterfehlstellenordung in GST gezielt zu manipulieren wurde mit einer Studie der Transporteigenschaften kombiniert. Die Anwendung von großflächigen Charakterisierungsmethoden wie XRD, Raman und IR-Spektroskopie, erlaubte die Bestimmung der Phase und des Fehlstellenordnungsgrades von GST und zeigte eindeutig, dass die Fehlstellenordnung für den Metall-Isolator-Übergang (MIT) verantwortlich ist. Insbesondere wird durch das Vergleichen von XRD-Messungen mit elektrischen Messungen gezeigt, dass der Übergang von isolierend zu leitend erfolgt, sobald eine Ordnung der Kristallgitterlücken einsetzt. Dieses Phänomen tritt in der kubischen Kristallphase auf, wenn Gitterfehlstellen in GST von einem ungeordneten in einen geordneten Zustand übergehen. Im zweiten Teil des Kapitels wird eine Kombination aus FIR- und Raman-Spektroskopie zur Untersuchung der Vibrationsmoden und des Ladungsträgerverhaltens in der amorphen und der kristallinen Phase angewendet, um Aktivierungsenergien für die Elektronenleitung, sowohl für die kubische, als auch für die trigonale Kristallphase von GST zu bestimmen. Hier ist es wichtig zu erwähnen, dass, in Übereinstimmung mit Ergebnissen aus anderen Untersuchungen, das Auftauchen eines MIT beim Übergang zwischen der ungeordneten und der geordneten kubischen Phase beobachtet wurde.
Schlussendlich wurden verschiedene sogenannte Pump/Probe Technik, bei der man das Material mit dem Laser anregt und die Röntgenstrahlung oder Terahertz (THz)-spektroskopie als Sonde nutzt, angewandt. Dies dient um ultra-schnelle Dynamiken zu erfassen, die zum Verständnis der Umschaltmechanismen nötig sind. Die Empfindlichkeit der THz-Messungen hinsichtlich der Leitfähigkeit, sowohl in GST, als auch in GeTe/Sb2Te3 Übergittern zeigte, dass die nicht-thermische Natur der Übergitterumschaltprozesse mit Grenzflächeneffekten zusammenhängt und . Der Ablauf wird mit beeindruckender geringer Laser-Fluenz erreicht. Dieses Ergebnis stimmt mit Berichten aus der Literatur überein, in denen ein Kristall-zu Kristallwechsel von auf Übergittern basierenden Speicherzellen für effizienter gehalten wird als GST Schmelzen, was zu einen ultra-schwachen Energieverbrauch führt.The growth by molecular beam epitaxy of Ge-Sb-Te (GST) alloys resulting in quasi-single-crystalline films with ordered configuration of intrinsic vacancies is demonstrated. It is shown how a structural characterization based on transmission electron microscopy, X-ray diffraction and density functional theory, allowed to unequivocally assess the vacancy ordering in GST samples, which was so far only predicted. The understanding of the ordering process enabled the realization of a fine tuning of the ordering degree itself, which is linked to composition and crystalline phase. A phase diagram with the different growth windows for GST is obtained. High degree of vacancy ordering in GST is also obtained through annealing and via femtosecond-pulsed laser crystallization of amorphous material deposited on a crystalline substrate, which acts as a template for the crystallization. This finding is remarkable as it demonstrates that it is possible to create a crystalline GST with ordered vacancies by using different fabrication procedures. Growth and structural characterization of GeTe/Sb2Te3 superlattices is also obtained. Their structure resembles that of ordered GST, with exception of the Sb and Ge layers stacking sequence. The possibility to tune the degree of vacancy ordering in GST has been combined with a study of its transport properties. Employing global characterization methods such as XRD, Raman and Far-Infrared spectroscopy, the phase and ordering degree of the GST was assessed, and unequivocally demonstrated that vacancy ordering in GST drives the metal-insulator transition (MIT). In particular, first it is shown that by comparing electrical measurements to XRD, the transition from insulating to metallic behavior is obtained as soon as vacancies start to order. This phenomenon occurs within the cubic phase, when GST evolves from disordered to ordered. In the second part of the chapter, a combination of Far-Infrared and Raman spectroscopy is employed to investigate vibrational modes and the carrier behavior in amorphous and crystalline phases, enabling to extract activation energies for the electron conduction for both cubic and trigonal GST phases. Most important, a MIT is clearly identified to occur at the onset of the transition between the disordered and the ordered cubic phase, consistently with the electrical study. Finally, pump/probe schemes based on optical-pump/X-ray absorption and Terahertz (THz) spectroscopy-probes have been employed to access ultrafast dynamics necessary for the understanding of switching mechanisms. The sensitivity of THz-probe to conductivity in both GST and GeTe/Sb2Te3 superlattices showed that the non-thermal nature of switching in superlattices is related to interface effects, and can be triggered by employing up to one order less laser fluences if compared to GST. Such result agrees with literature, in which a crystal to crystal switching of superlattice based memory cells is expected to be more efficient than GST melting, therefore enabling ultra-low energy consumption.
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Adhikari, Pan P. "Optical Study of Inter-band Transitions in Topological Insulators Bi2Se3, Bi2Te3, and Sb2Te3." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1497994862971012.
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LONGO, EMANUELE MARIA. "HETEROSTRUCTURES BASED ON THE LARGE-AREA Sb2Te3 TOPOLOGICAL INSULATOR FOR SPIN-CHARGE CONVERSION." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/311358.
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I dispositivi elettronici che sfruttano proprietà legate allo spin elettronico costituiscono un settore molto promettente per lo sviluppo della nanoelettronica del futuro. Recentemente, gli isolanti topologici tridimensionali (IT-3D), quando posti a contatto con materiali ferromagnetici (FM), giocano un ruolo centrale nel contesto del miglioramento dell’efficienza di conversione tra spin e carica elettronici in eterostrutture di tipo FM/TI. L’oggetto principale di questa tesi è lo studio delle interazioni chimico-fisiche tra l’IT-3D Sb2Te3, nelle sue forme granulare ed epitassiale, con film di Fe e Co attraverso l’uso di tecniche di Diffrazione/Riflettività di raggi-X, spettroscopia di risonanza ferromagnetica (FMR) e pompaggio di spin in risonanza ferromagnetica (SP-FMR). In concomitanza con l’ottimizzazione delle proprietà dei materiali, un particolare interesse è stato rivolto verso l’impatto industriale della ricerca presentata. Per questo motivo, per la produzione di Sb2Te3 e di alcuni dei FM impiegati, sono state impiegate tecniche di deposizione di materiali su larga scala ( 4 pollici), quali la Metal Organic Chemical Vapor Deposition (MOCVD) e l’Atomic Layer Deposition (ALD) rispettivamente.
Una approfondita caratterizzazione chimica, strutturale e magnetica dell’interfaccia Fe/ Sb2Te3-granulare ha evidenziato un marcato intermixing tra i materiali e una generale tendenza degli atomi di Fe nel legare con l’elemento calcogenuro quando presente in un IT. Attraverso trattamenti termici rapidi e a bassa temperatura sottoposti sui film di Sb2Te3 granulare prima della crescita del Fe, l’interfaccia Fe/Sb2Te3-granulare è risultata morfologicamente più netta e chimicamente stabile. Lo studio di film sottili di Co cresciuti attraverso ALD su Sb2Te3 granulare ha permesso la produzione di interfacce Co/Sb2Te3-granulare di alta qualità, con la possibilità inoltre di modificare le proprietà magneto-strutturali dei film di Co attraverso una selezione appropriata di substrati.
Con l’obbiettivo di migliorare le proprietà dei film di Sb2Te3, dei trattamenti termici specifici sono stati condotti su Sb2Te3 granulare appena cresciuto, ottenendo film di Sb2Te3 altamente orientati con una qualità cristallina vicina al cristallo singolo di tipo epitassiale. Questi substrati di Sb2Te3 sono stati utilizzati per produrre eterostrutture di Au/Co/Sb2Te3-epitassiale e Au/Co/Au/Sb2Te3-epitassiale per studiare la loro risposta di FMR. I dati di FMR per il campione Au/Co/Sb2Te3-epitassiale sono stati interpretati considerando un contributo di Two Magnon Scattering (TMS) dominante, verosimilmente a causa della presenza di rugosità magnetica all’interfaccia Co/Sb2Te3-epitassiale. L’introduzione di un interlayer di Au per evitare il contatto diretto tra Co e Sb2Te3 si è dimostrato vantaggioso per la totale eliminazione del contributo di TMS.
Misure di SP-FMR sono state condotte sulla struttura ottimizzata Au/Co/Au/Sb2Te3-epitassiale, sottolineando il ruolo giocato dallo strato di Sb2Te3-epitassiale nel processo di SP. I segnali di SP ricavati da campioni di Au/Co/Au/Si(111) e Co/Au/Si(111) sono stati utilizzati per determinare l’efficienza di conversione spin-carica ottenuta dall’introduzione dello strato di Sb2Te3. L’efficienza estratta è stata calcolata interpretando i dati di SP-FMR attraverso i modelli di effetto Edelstein inverso ed effetto di Spin-Hall inverso, i quali hanno dimostrato che l’IT-3D Sb2Te3 è un candidato promettente per essere impiegato nella prossima generazione di dispositivi spintronici.Spin-based electronic devices constitute an intriguing area in the development of the future nanoelectronics. Recently, 3D topological insulators (TI), when in contact with ferromagnets (FM), play a central role in the context of enhancing the spin-to-charge conversion efficiency in FM/TI heterostructures. The main subject of this thesis is the study of the chemical-physical interactions between the granular and epitaxial Sb2Te3 3D-TI with Fe and Co thin films by means of X-ray Diffraction/Reflectivity, Ferromagnetic Resonance spectroscopy (FMR) and Spin Pumping-FMR. Beside the optimization of the materials properties, particular care was taken on the industrial impact of the presented results, thus large-scale deposition processes such as Metal Organic Chemical Vapor Deposition (MOCVD) and Atomic Layer Deposition (ALD) were adopted for the growth of the Sb2Te3 3D-TI and part of the FM thin films respectively. A thorough chemical, structural and magnetic characterization of the Fe/granular Sb2Te3 interface evidenced a marked intermixing between the materials and a general bonding mechanism between Fe atoms and the chalcogen element in chalcogenide-based TIs. Through rapid and mild thermal treatments performed on the granular Sb2Te3 substrate prior to Fe deposition, the Fe/granular-Sb2Te3 interface turned out to be sharper and chemically stable. The study of ALD-grown Co thin films deposited on top of the granular-Sb2Te3 allowed the production of high-quality Co/granular-Sb2Te3interfaces, with also the possibility to tune the magneto-structural properties of the Co layer through a proper substrate selection. In order to improve the structural properties of the Sb2Te3, specific thermal treatments were performed on the as deposited granular Sb2Te3, achieving highly oriented films with a nearly epitaxial fashion. The latter substrates were used to produce Au/Co/epitaxial-Sb2Te3 and Au/Co/Au/epitaxial-Sb2Te3 and the dynamic of the magnetization in these structures was investigated studying their FMR response. The FMR data for the Au/Co/Sb2Te3 samples were interpreted considering the presence of a dominant contribution attributed to the Two Magnon Scattering (TMS), likely due to the presence of an unwanted magnetic roughness at the Co/epitaxial-Sb2Te3 interface. The introduction of a Au interlayer to avoid the direct contact between Co and Sb2Te3 layers was shown to be beneficial for the total suppression of the TMS effect. SP-FMR measurements were conducted on the optimized Au/Co/Au/epitaxial-Sb2Te3 structure, highlighting the role played by the epitaxial Sb2Te3substrate in the SP process. The SP signals for the Au/Co/Au/Si(111) and Co/Au/Si(111) reference samples were measured and used to determine the effective spin-to-charge conversion efficiency achieved with the introduction of the epitaxial Sb2Te3 layer. The extracted SCC efficiency was calculated interpreting the SP-FMR data using the Inverse Edelstein effect and Inverse Spin-Hall effect models, which demonstrated that the Sb2Te3 3D-TI is a promising candidate to be employed in the next generation of spintronic devices.
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Kowalczyk, Philippe. "Super-réseaux GeTe/Sb2Te3 pour les mémoires iPCM : croissance PVD par épitaxie van der Waals et étude de leur structure." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAT109/document.
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Afin de faire face à la demande croissante de mémoires de plus en plus performantes dans les systèmes informatiques, de nouvelles technologies se sont développées. Parmi elles, les mémoires résistives à changement de phase (ou PCM pour Phase-Change Memory) ont des propriétés et une maturité suffisante pour développer les nouvelles mémoires SCM (pour Storage Class Memory) comme en témoigne la récente commercialisation des produits Optane par la firme INTEL®. Néanmoins, la consommation énergétique des PCM lors de leur programmation reste élevée, ce qui limite leurs performances. L’intégration de super-réseaux (GeTe)2/(Sb2Te3)m dans des mémoires dites iPCM (pour interfacial Phase-Change Memory) est une des voies les plus prometteuse pour permettre une diminution significative des courants de programmation. Cependant, le mécanisme de transition des iPCM et la structure du matériau dans ses deux états de résistances sont encore méconnus. Dans ce contexte, l’objectif de cette thèse est d’élaborer des super-réseaux (GeTe)2/(Sb2Te3)m (m=1,2,4 et 8) cristallins, de déterminer leur structure puis de les intégrer dans des dispositifs mémoires. La pulvérisation cathodique alternée des matériaux GeTe et Sb2Te3 dans un équipement industriel de dépôt est utilisée pour effectuer l’épitaxie van der Waals de ces super-réseaux. Une optimisation du procédé par l’ajout d’une cible de Te en co-pulvérisation avec la cible de Sb2Te3 montre l’obtention de super-réseaux stœchiométriques présentant la périodicité souhaitée, ainsi qu’une orientation des plans cristallins (0 0 l) parallèle à la surface du substrat. Une description de l’ordre atomique local des super-réseaux ainsi optimisés est ensuite menée par l’étude d’images HAADF-STEM couplée à des simulations. Celle-ci révèle un phénomène d’inter-diffusion entre les couches de GeTe et de Sb2Te3 déposées aboutissant à la formation locale de GexSbyTez rhomboédriques, des mesures quantitatives de l’occupation des plans atomiques en Ge/Sb confirment aussi le phénomène. De plus, un modèle de structure à longue distance de ces super-réseaux considérant un empilement aléatoire de blocs cristallins permet la simulation des courbes de diffraction obtenues expérimentalement. Enfin, les premières intégrations des super-réseaux (GeTe)2/(Sb2Te3)m dans des dispositifs mémoires mettent en évidence une réduction importante des courants de programmation jusqu’à 4 fois inférieurs à une PCM et avec une endurance dépassant les 10 millions cyclesIn order to satisfy the demand for more and more efficient memory in computer systems, new technologies have been developed. Among the latter resistive phase-change memories (PCM) exhibit capacities and sufficient maturity to achieve the so-called new SCM (for Storage Class Memory) devices as evidenced by the recent commercialization of Optane products by INTEL®. Nevertheless, PCM still require strong electrical consumption limiting their performance. Integration of (GeTe)2/(Sb2Te3)m superlattices in so-called iPCM (for interfacial Phase Change Memory) was shown to permit a significant decrease in programming currents. However, the switching mechanism of this memory and the structure of the material in its two resistance states are still under debate. The aim of this thesis is therefore to deposit crystalline (GeTe)2/(Sb2Te3)m (m=1,2,4 et 8) superlattices, to determine their structure and to integrate them into memory devices. GeTe and Sb2Te3 materials are alternately deposited by means of sputtering in an industrial deposition tool to perform van der Waals epitaxy of these superlattices. Stoichiometric superlattices with the desired periodicity and with an orientation of the (0 0 l) crystalline planes parallel to the surface of the substrate are obtained by innovative co-sputtering of Sb2Te3 and Te targets during Sb2Te3 deposition. A description of the local atomic order of superlattices is then carried out by studying HAADF-STEM images coupled to simulations. Intermixing between GeTe and Sb2Te3 deposited layers is thus revealed, leading to the local formation of rhombohedral GexSbyTez. Quantitative measurements of the Ge/Sb atomic plans occupation in further confirm the phenomenon. A long-range order structural model of superlattices by means of random stacking of crystalline blocks allows the simulation of experimental diffraction curves. Finally, the first integrations of (GeTe)2/(Sb2Te3)m (with m=1,2,4 et 8) superlattices in devices demonstrate a programming current up to 4 times lower than a PCM reference with an endurance exceeding 10 millions cycles
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Shayduk, Roman. "Molecular beam epitaxy of GeTe-Sb2Te3 phase change materials studied by X-ray diffraction." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16243.
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Die monolithische Integration von Phasenwechselmaterialien mit Halbleiter-Hetero\-strukturen er\"offnet neue Perspektiven f\"ur zuk\"unftige Generationen von nichtfl\"uchtigen Speicherbauelementen. %Epitaktische Phasenwechselmaterialien erm�glichen detaillierte %Studien der strukturellen �nderungen w�hrend des Phasen�bergangs und %erlauben eine Bestimmung der Skalierungslimits zuk�nftiger %Datenspeicher. Diese Arbeit befasst sich mit dem epitaktischen Wachstum von Ge-Sb-Te Phasenwechselmaterialien. Dazu wurden Ge-Sb-Te(GST) Schichten mittels Molekularstrahlepitaxie (MBE) auf GaSb(001)-Substraten abgeschieden. Die kristallografische Orientierung und die Ver\"anderungen der Gitterkonstante w\"ahrend des Wachstums wurden mittels R\"ontgenbeugung unter streifendem Einfall (GIXRD) bestimmt. Das Nukleationsverhalten zu Beginn des Wachstums wurde mittels Hochenergie-Elektronenbeugung unter streifendem Einfall (RHEED) untersucht.The integration of phase change materials into semiconductor heterostructures may lead to the development of a new generation of high density non-volatile phase change memories. Epitaxial phase change materials allow to study the detailed structural changes during the phase transition and to determine the scaling limits of the memory. This work is dedicated to the epitaxial growth of Ge-Sb-Te phase change alloys on GaSb(001). We deposit Ge-Sb-Te (GST) films on GaSb(001) substrates by means of molecular beam epitaxy (MBE). The film orientation and lattice constant evolution is determined in real time during growth using grazing incidence X-ray diffraction (GID). The nucleation stage of the growth is studied \emph{in situ} using reflection high energy electron diffraction (RHEED).
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Azzouz, Yassine. "Etude de la croissance et des propriétés thermoélectriques du Bi2Te3, Sb2Te3 et de l'alliage BixSb2." Montpellier 2, 1990. http://www.theses.fr/1990MON20213.
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Le choix des materiaux pour les applications thermoelectriques depend essentiellement de la valeur de leur coefficient de merite. Nous avons obtenu des valeurs optimales en utilisant les semiconducteurs v2v13: telluride de bismuth et le telluride d'antimoine deposes par la technique du jet moleculaire. Nous avons fait croitre des couches de bi2te3, sb2te3 et bixsb2-xte3 sur un substrat amorphe. Nous avons etudie la composition et les proprietes cristallographiques des couches en fonction du rapport des flux moleculaires et de la temperature de substrat. Nous avons montre egalement que les proprietes thermoelectriques: nombre de porteurs, mobilite et pouvoir thermoelectrique dependent de la temperature de substrat et de la concentration atomique. Des thermopiles de puissance et des capteurs de puissance hyperfrequence a effet seebeck ont ete realises a base de ces materiaux. Concernant leur parametre essentiel, le coefficient de seebeck du couple (bi2te3(n), sb2te3(p)) est huit fois plus grand que celui du couple usuel (cu, constantan)
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Winkler, Markus [Verfasser], and Oliver [Akademischer Betreuer] Eibl. "Nanostructured thermoelectrics : Bi2Te3 / Sb2Te3 based superlattice systems fabricated by MBE and sputtering / Markus Winkler ; Betreuer: Oliver Eibl." Tübingen : Universitätsbibliothek Tübingen, 2015. http://d-nb.info/1163321079/34.
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Wang, Rui Ning [Verfasser], Henning [Gutachter] Riechert, Fulvia [Gutachter] Patella, and Raffaella [Gutachter] Calarco. "Epitaxial growth and characterization of GeTe and GeTe/Sb2Te3 superlattices / Rui Ning Wang ; Gutachter: Henning Riechert, Fulvia Patella, Raffaella Calarco." Berlin : Humboldt-Universität zu Berlin, 2017. http://d-nb.info/1189327910/34.
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Bragaglia, Valeria [Verfasser], Henning [Gutachter] Riechert, Simone [Gutachter] Raoux, and David [Gutachter] Wright. "Epitaxial Growth and Ultrafast Dynamics of GeSbTe Alloys and GeTe/Sb2Te3 Superlattices / Valeria Bragaglia ; Gutachter: Henning Riechert, Simone Raoux, David Wright." Berlin : Humboldt-Universität zu Berlin, 2017. http://d-nb.info/1185579133/34.
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Kosalathip, Voravit. "Synthèse et caractérisation microstructurale de poudres nanométriques à base de Bi2Te3 et Sb2Te3 : contribution à l'état de l'art des nanocomposites thermoélectriques." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL033N/document.
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L’étude de matériaux thermoélectriques nanocomposites et nanostructurés est en plein essor suite à l’intérêt de multiplier le nombre d’interfaces et de diminuer la taille des objets pour améliorer les performances. Nous avons mis au point une nouvelle méthode de préparation de nanopoudres thermoélectriques de type n (Bi0.95Sb0.05)2(Te0.95Se0.05)3 et de type p (Bi0.2Sb0.8)2Te3, à partir de la fracturation laser en milieu aqueux de poudres de taille micrométrique. La cellule de préparation développée permet d’obtenir par jour environ 200 mg de poudres nanométriques cristallisés présentant la structure cristallographique des poudres initiales et dont la taille moyenne est comprise entre 7 et 12 nm. Les mécanismes mis en jeu dans l’obtention des nanoparticules ont été abordés. Ils dépendent fortement de la densité d’énergie du faisceau laser. Les nanopoudres ont ensuite été mélangées mécaniquement aux poudres micrométriques de même nature et ont été compactées à froid. Les propriétés thermoélectriques (résistivité électrique, pouvoir thermoélectrique, conductivité thermique) des nanocomposites ont été évaluées à température ambiante. Les premiers résultats montrent que même si le pouvoir thermoélectrique est maintenu dans les matériaux nanostructurés et nanocomposites et que la conductivité thermique totale peut, de manière tout à fait exceptionnelle, être diminuée d’un facteur deux, la résistivité électrique obtenue est jusqu’alors trop élevée pour conduire à de bonnes performances en terme de facteur de mérite adimensionnel, par rapport à un matériau massif conventionnel de même compositionThe study of thermoelectric nanostructured and nanocomposite materials is expanding because of the interest to multiply the number of interfaces and to decrease the size of the objects in order to improve the thermoelectric performance. We developed a new method to prepare thermoelectric n type (Bi0.95Sb0.05)2(Te0.95Se0.05)3 and p type (Bi0.2Sb0.8)2Te3 nanopowders, from the laser fracture in a liquid medium of powders of micrometric size. The developed cell preparation makes it possible to obtain per day approximately 200 mg of crystallized nanometric powders having the crystallographic structure of the initial powders and whose mean size lies between 7 and 12 nm. The mechanisms concerned in obtaining the nanoparticules were approached. They strongly depend on the density of energy of the laser beam. The nanopowders then were mechanically mixed with the micrometric powders of comparable nature and were cold pressed. The thermoelectric properties (electrical resistivity, thermoelectric power, thermal conductivity) of the nanocomposites were evaluated at room temperature. The first results show that even if the thermoelectric power is maintained in nanostructured and nanocomposite materials and that the total thermal conductivity can, in a completely exceptional way, being decreased by a factor two, the electrical resistivity obtained is hitherto too high to lead to high values of the dimensionless thermoelectric figure of merit, with regard to conventional bulk materials of same composition
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Kosalathip, Voravit Dauscher Anne. "Synthèse et caractérisation microstructurale de poudres nanométriques à base de Bi2Te3 et Sb2Te3 contribution à l'état de l'art des nanocomposites thermoélectriques /." S. l. : INPL, 2008. http://www.scd.inpl-nancy.fr/theses/2008_KOSALATHIP_V.pdf.
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Poffo, Claudio Michel. "Estudo dos efeitos de altas pressões nas propriedades estruturais e ópticas das ligas nanoestruturadas FeSb2 e Sb2Te3 produzidas por moagem mecânica." reponame:Repositório Institucional da UFSC, 2013. http://repositorio.ufsc.br/handle/123456789/103525.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Florianópolis, 2013.Made available in DSpace on 2013-07-16T21:07:25Z (GMT). No. of bitstreams: 1 316599.pdf: 2616486 bytes, checksum: 886fd2ef3956654c67a8a0360eae3bd7 (MD5)
Os materiais nanoestruturados (MN) FeSb2 e Sb2Te3 foram produzidos por moagem mecânica (MM) e tiveram suas propriedades estruturais e ópticas investigadas na condição de altas pressões, através de medidas in situ de padrões de difração de raios X (DRX) e espectros Raman (ER). As propriedades estruturais, térmicas e ópticas para a liga FeSb2 também foram estudadas nas condições ambiente, através de medidas de DRX, ER, calorimetria diferencial de varredura (DSC - Differential Scanning Calorimetry) e transmitância óptica (TO). Medidas in situ de DRX e ER em função da pressão foram realizadas para a liga FeSb2 para pressões até 28.2 e 45.2 GPa, respectivamente. As medidas de DRX revelaram que, com o aumento da pressão, ocorre degradação da fase ortorrômbica S.G Pnnm (fase I) estável em condições ambiente. Aumento de fração volumétrica de uma fase amorfa, nucleada durante o processo de MM é observado. A fração volumétrica da fase amorfa é máxima em 23.3 GPa. Entre 14.3 e 23.3 GPa uma fase tetragonal, com grupo espacial (S.G - space group) I4/mcm (fase II) é nucleada, porém até a máxima pressão aplicada, 28.2 GPa, não foi observada nenhuma transição total da fase I para a fase II através de medidas de DRX. Medidas de ER revelam que, para pressões acima de 21 GPa, o modo Raman ativo A1g referente a fase II começa a ser fracamente observado. Para maiores pressões, medidas de ER revelam uma transição da fase I para a fase II. Medidas de DRX e ER in situ em função da pressão foram realizadas para a liga Sb2Te3 para pressões até 19.2 e 25.5 GPa, respectivamente. As medidas DRX revelaram uma sequência de transições de fases: (1) A fase romboédrica (fase I), S.G R-3m, estável em condições ambientes, se transforma completamente em uma fase ortorrômbica (fase II), S.G C2/m, em torno de 13.2 GPa. (2) Entre 15.2 e 19.2 GPa, a fase II inicia uma transformação para uma terceira fase ortorrômbica (fase III), S.G C2/c. Em 19.2 GPa ainda há vestígios da fase II. Uma transição topológica eletrônica (ETT - electronic topological transition) foi observada através de medidas de DRX e ER em uma pressão em torno de 3.7 GPa.
Abstract : Nanostructured materials (NM) FeSb2 e Sb2Te3 were produced by mechanical milling (MM). Their structural and optical properties were investigated under high pressure condition, via in situ measurements of patterns of X-ray diffraction patterns (XRD), and Raman spectra (RS). The structural, thermal and optical properties of FeSb2 were also studied of ambient conditions by XRD, RS, differential scanning calorimetry (DSC) and optical transmittance (OT). In situ XRD and RS measurements as a function of pressure were performed for the FeSb2 alloy for pressures up to 28.2 and 45.2 GPa, respectively. XRD measurements reveal that, with increasing pressure, degradation of the orthorhombic phase (phase I), S.G Pnnm, occurs. An increase in the volume fraction of an amorphous phase, nucleated during the MM process, is observed. The volume fraction of the amorphous phase is maximum at 23.3 GPa. Between 14.3 and 23.3 GPa a tetragonal phase, space group S.G I4/mcm (phase II) is nucleated, but until the maximum applied pressure, 28.2 GPa, the complete transition from phase I to phase II was not observed by XRD measurements. ER measurements show that for pressures above 21 GPa, the Raman active mode A1g, relative of phase II, begins to be faintly observed. For pressures higher than 21 GPa, measures of RS reveal a transition from phase I to phase II. XRD and RS measurements as a function of pressure were performed for the Sb2Te3 alloy for pressures up to 19.2 and 25.5 GPa, respectively. XRD measurements reveal a sequence of phase transitions: (1) the rhombohedra phase (phase I) with space group S.G R-3m, stable at ambient conditions, is completely transformed into a orthorhombic phase, S.G C2/m (phase II) around 13.2 GPa. (2) between 15.2 and 19.2 GPa, phase II begins a transformation to a third orthorhombic phase (phase III) with S.G C2/c. At 19.2 GPa there is still some remain of phase II. An electronic topological transition (ETT) was observed around 3.7 GPa.
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Ameziane, Jamal. "Etude physico-chimique des conditions d'élaboration de jonctions de semi-conducteurs V2VI3. Application à la réalisation d'homojonctions Bi2Te3/Bi2Te3 et d'hétérojonctions Sb2Te3/Bi2Te3." Montpellier 2, 1993. http://www.theses.fr/1993MON20131.
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Le travail de these a pour but de mettre en evidence la faisabilite d'heterostructures de type bi#2te#3/sb#2te#3. Pour cela l'auteur utilise toutes les methodes qui sont a la disposition d'un laboratoire de chimie du solide. Le travail a ete effectue en collaboration avec le laboratoire de centre d'electronique de montpellier ce qui montre le souci de finalisation de ce travail. L'ouvrage peut se scinder en deux parties. Dans une premiere partie on etudie les caracteristiques des materiaux bi#2te#3 et sb#2te#3 sur le plan de leurs proprietes thermoelectriques ainsi que sur le plan des equilibres de phases heterogenes dont l'apport est utilise dans la deuxieme partie. Cette derniere partie concerne l'aspect experimental du probleme. On etudie par la technique des jets moleculaires. Les conditions de croissance des composes bi#2te#3 et sb#2te#3 sont definies. En particulier on a etudie la composition des couches qui ont ete determinees en fonction de la temperature et du rapport des flux incidents de matiere. Dans le domaine de stchiometrie correspondant aux materiaux etudies on a pu definir la transition amorphe cristallise
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Shayduk, Roman [Verfasser], Klaus H. [Akademischer Betreuer] Ploog, Ted [Akademischer Betreuer] Masselink, and Andreas [Akademischer Betreuer] Wieck. "Molecular beam epitaxy of GeTe-Sb2Te3 phase change materials studied by X-ray diffraction / Roman Shayduk. Gutachter: Klaus H. Ploog ; Ted Masselink ; Andreas Wieck." Berlin : Humboldt Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://d-nb.info/1014974909/34.
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Stellhorn, Jens Rüdiger Verfasser], and Wolf-Christian [Akademischer Betreuer] [Pilgrim. "Short- and Intermediate-Range Structures in GeTe-Sb2Te3 and Ag-GeSe3 Glasses Studied by Anomalous X-Ray Scattering / Jens Rüdiger Stellhorn. Betreuer: Wolf-Christian Pilgrim." Marburg : Philipps-Universität Marburg, 2015. http://d-nb.info/1077866852/34.
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Stellhorn, Jens Rüdiger [Verfasser], and Wolf-Christian [Akademischer Betreuer] Pilgrim. "Short- and Intermediate-Range Structures in GeTe-Sb2Te3 and Ag-GeSe3 Glasses Studied by Anomalous X-Ray Scattering / Jens Rüdiger Stellhorn. Betreuer: Wolf-Christian Pilgrim." Marburg : Philipps-Universität Marburg, 2015. http://d-nb.info/1077866852/34.
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Purelis, Valdemaras. "SbSI(Sb2Se3)0,25 kristalų virpesių spektrų tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20080924_182332-41068.
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SbSI(Sb2Se3)0,25 kristalai išauginti Kietojo kūno optinėje mokslinėje laboratorijoje. Jie sudaryti iš SbSI grandinėlių ir Sb2Se3 domenų, nusitęsusių c(z) kristalografinės ašies kryptimi. Jeigu gryname SbSI kristale grandinėlės yra nesuspaustoje būsenoje (Tc =295 K). Suspaustų SbSI grandinėlių feroelektrinio fazinio virsmo temperatūra išauga. Pasaulinėje literatūroje nėra duomenų, kokia SbSI(Sb2Se3)0,25 kristalo feroelektrinio fazinio virsmo temperatūra Tc.The SbSI(Sb2Se3)0,25 crystals are grown in the Optical science laboratory of solid body. They are made from SbSI chains and Sb2Se3 domains, which extend c(z) to the crystallographic axis vector. If the clear SbSI crystals chases are in uncompressed phase (Tc = 295K), the temperature in ferroelectrics phase transformation grows. There is no data in literature about the SbSI(Sb2Se3)0,25 crystals ferroelectric transition temperature Tc.
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Meyer, Thibaut. "Gravure du verre de chalcogénure GeSbSe en plasma fluoré ou à base de méthane." Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4064.
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Notre étude est focalisée sur la gravure du verre de chalcogénure GeSbSe en plasmas de SF6, SF6/Ar et CH4/H2/Ar. Ce travail s’étend aux éléments purs Ge, Sb et Se ainsi qu’aux binaires GeSe2et Sb2Se3. Une partie de ce travail est portée sur l’identification des produits de gravure fluorés, hydrures et hydrocarbonés à la surface des matériaux et dans le plasma. La spectrométrie de masse a permis d’enregistrer des spectres très riches comportant des produits jusque-là non identifiés dans la littérature.En plasmas fluorés, la composition de surface affecte la rugosité et la vitesse de gravure. De plus, la formation de produits de gravure fluorés et non volatils (SeSbFx) induit un effet de micro-masquage. Pour cette raison, nous avons cherché à diminuer la vitesse de formation des produits SeSbFx. Ainsi, l’ajout d’argon au précurseur SF6 a réduit significativement la concentration de fluor atomique à la surface pour de hautes proportions d’argon (>90%) et de basses pressions (<2mTorr). Pour ces dernières conditions, la gravure a généré une surface lisse (< 5nm), une vitesse de gravure correcte (>50 nm/min) ainsi qu’un profil quasi-anisotrope.Pour s’affranchir des produits de gravure non volatils, nous avons exploré la chimie CH4/H2/Ar. Cette dernière s’est également révélée très efficace pour graver l’antimoine tout en gardant des caractéristiques de gravure viables. Nous avons identifié les produits GexCyHz comme responsablesde la rugosité pour de hautes pressions (>3mTorr) ou de hautes proportions de méthane (>30%). Outre la capacité de graver le verre GeSbSe, un tel plasma est une alternative prometteuseThis study is focused on the etching of the GeSbSe chalcogenide glass in SF6, SF6/Ar et CH4/H2/Ar plasmas. This work is extended to the etching of pure elements Ge, Sb, Se along with binary materials GeSe2 et Sb2Se3. A part of this work is dedicated to the identification of fluoride, hydride and hydrocarbon etching products at the surface of the materials and inside the plasma. Mass spectrometry analysis shows rich spectra containing some unheard-of products.In fluorine-based plasmas, the surface composition affects the surface roughness and the etch rate. Inevitably, the formation of non-volatile fluorine products (SeSbFx) induces micromasking effects. This is the reason why we have sought to slow down the SeSbFx kinetic formation by adding Ar to SF6. Using that mixture, we managed to reduce the fluorine atomic concentration at the surface for high content of Ar (>90%) and for a lower pressure (<2mTorr). With such conditions, we obtained a smooth surface (<5nm), an acceptable etch rate (>50 nm/min) and a quasi-anisotropic profile. To free from non-volatile halogen products, we explored the CH4/H2/Ar chemistry. The latter efficiently etched the antimony while having viable etching characteristics. Surface analyses showed that the GexCyHz products are linked to the roughness for higher pressure (>3mTorr) and a significant CH4 content (>30%). In addition to the capacity to etch the GeSbSe glass, such plasma is a promising alternative
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Ežerinskienė, Edita. "SbSI + 15% Sb2S3 kristalų virpesių tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2007. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2007~D_20070816_165153-68277.
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1. Eksperimentiniai SbSI +15% Sb2S3 kristalų atspindžio spektro tyrimai patvirtino, kad mūsų išaugintuose SbSI +15% Sb2S3 kristaluose feroelektrinis fazinis virsmas vyksta temperatūroje TC = 330 K. SbSI kristalai temperatūrų srityje T > TC yra paraelektrinėje fazėje, o temperatūrų srityje T < TC yra feroelektrinėje fazėje.
2. SbSI +15% Sb2S3 kristalų teoriniai normaliųjų virpesių harmoniniame artėjime dažniai sutampa su eksperimentinais dažniais, kai > 50 cm-1. Spektro srityje < 50cm-1 normaliųjų virpesių dažniai nesutampa su ekperimentinais dažniais, nes šioje srityje normaliųjų modų virpesiai yra stipriai anharmoniniai.
3. Teoriniai SbSI +15% Sb2S3 kristalų normaliųjų modų dažnių priklausomybių nuo temperatūros harmoniniame artinyje tyrimas parodė, kad arti TC = 330 K stebimos anomalijos. Šios anomalijos sutampa su eksperimentiniais dažniais tik spektro srityje > 50 cm-1 . Anomalijas sąlygoja elementariosios gardelės tūrio kitimas.
4. Spektro srityje = 50 cm-1 minkštųjų modų temperatūrinė priklausomybė ir TC pokytis yra sąlygoti V(z) anharmoninių narių, kuriuos s��lygoja fononų sąveika su fononais.
SbSI ir SbSI +15% kristalų Sb atomo potencines energijos V(z) priklausomybės nuo žemo dažnio B1U modos normaliųjų koordinačių ašies kryptimi anharmoniniame artinyje parodė.
1. SbSI kristale, kurio grandinėlės yra nesuspaustos - ašies kryptimi arti V(z) potencialinis barjeras .
2. SbSI +15% kristaluose SbSI grandinėlės yra suspaustos Sb2S3 domenų... [toliau žr. visą tekstą]SbSI +15% Sb2S3 crystals have been grown from the solution. Reflection spectra of the SbSI +15% Sb2S3 crystals were studied by a modernized Fourier spectrometer using an improved Kramers-Kroning technique with two confining spectral limits, the spectra of optical parameters and optical functions were calculated. The vibrational frequencies and have been evaluated. The vibrational frequencies of SbSI chains with displaced Sb3 and Sb4 atoms along x-axis from their equilibrium positions in different phases have been calculated in the harmonic approximation. The theoretical results are compared with experimental data. Taking into account the unharmonicity of the electronic structure and lattice caused mainly by the phonon-phonon interaction, the phase transition temperature Tc has been calculated. The dependence of the potential energy function of the soft B1U mode upon temperature determines variation of the frequency in the phase transition region.
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Nowka, Christian. "Untersuchungen zu Gasphasentransporten in quasibinären Systemen von Bi2Se3 mit Bi2Te3, Sb2Se3, MnSe und FeSe zur Erzeugung von Nanokristallen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-216927.
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In Topologischen Isolatoren (TI) werden metallische Zustände an der Oberfläche beobachtet, während die entsprechenden Volumenzustände eine Bandlücke aufweisen. Der Volumenbeitrag zur Leitfähigkeit von TI-Materialien macht eine Synthese von Nanokristallen bzw. eine Dotierung nötig. Der Fokus der Untersuchungen dieser Arbeit liegt dabei auf der Erzeugung von Nanokristallen der TI-Materialien Bi2Te3- und Bi2Te2Se sowie dotierter Bi2Se3-Nanokristallen.
Die Synthese der Nanokristalle erfolgte durch den Gasphasentransport im geschlossenen System über den Mechanismus einer Zersetzungssublimation bzw. unter dem Einsatz eines Transportmittels. Für eine erfolgreiche Erzeugung der Nanokristalle sind im Vorfeld thermodynamische Modellierungen des Gasphasentransports sowie Versuche zum chemischen Transport für die quasibinären Systeme Bi2Se3-Bi2Te3, Bi2Se3-Sb2Se3 und Bi2Se3-FeSe sowie für das ternäre System Mn-Bi-Se durchgeführt worden.
Durch Versuche zum chemischen Transport konnten die Aussagen der Modellierung bestätigt und im Weiteren der Dotandengehalt in den abgeschiedenen Kristallen sowie der Einlagerungsmechanismus durch Ergebnisse aus XRD- und ICP-OES-Untersuchungen beschrieben werden. Die Synthese bzw. Dotierung der Nanokristalle wurde hauptsächlich durch die Transportrate und den Dampfdruck des Dotanden bestimmt.
In den Systemen Bi2Se3-Bi2Te3 und Bi2Se3-Sb2Se3 ist ein Gasphasentransport über eine Zersetzungssublimation durchführbar und resultierte in einer erfolgreichen Darstellung von Bi2Te3- und Bi2Te2Se-Nanokristallen sowie von dotierten (SbxBi1-x)2Se3-Nanokristallen. Entgegen dessen erfolgte der Gasphasentransport in den Systemen Bi2Se3-FeSe und Mn-Bi-Se unter Verwendung eines Transportmittels. Hierbei verringerten die gesteigerten Transportraten das Wachtum von Nanokristallen. Im Weiteren gelang es dotierte (Fe,Mn)xBi2-xSe3-Volumenkristalle sowie MnBi2Se4-Einkristalle darzustellen und mittels XRD, ICP-OES, magnetischer Messungen sowie elektrischem Transport zu charakterisieren.
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Ciórcero, Juliane Rutckeviski. "ESTUDO DA SUBSTITUIÇÃO DE Nb2O5 POR Sb2O3 E EFEITO DA CALCINAÇÃO SOBRE A MICROESTRUTURA E PROPRIEDADES ELÉTRICAS DE VARISTORES DE SnO2." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2011. http://tede2.uepg.br/jspui/handle/prefix/1407.
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Previous issue date: 2011-12-19Conselho Nacional de Desenvolvimento Científico e Tecnológico
This work studied systematically the substitution of Nb2O5 by Sb2O3 in composition of a ternary varistor system and study of calcination of binary and multi-component systems and their relationship microstructure-electric property. In part I of the work, study of substitution of Nb2O5 by Sb2O3, the compositions were prepared by conventional ceramic processing and dried by "spray-dryer" Pellets were produced at 25 MPa and sintering was produced at 1350ºC/ 2h.Increasing the concentration of Sb2O3, the nonlinear behavior of ceramics was reduced, accompanied by the reduction of the breakdown electric field and increased leakage current. With increasing concentration of 0.05% Sb2O3 to 0.5% (mol%), the samples were more porous, suggesting that higher concentrations of Sb2O3 decreases the rate of sintering. This decrease was linked to the increased concentration of tin vacancies that leads to nondensifying processes. In part II, was studied the influence of calcination (700oC, 1000oC and 1200oC) of binary and multi-component systems. The compositions were prepared by the conventional method, with the addition of the calcination process. The samples were comformed at 75 MPa and sintered at 1300oC for systems calcined at 1200oC and 1300oC, and at 1350oC for systems calcined at 700oC and 1000oC. Some studied systems have showed cassiterite phase associated to the SnO phase. With the addition of dopants, there was an increase in density of the systems, and the increase in temperature of sintering also led to a slight increase in density. The addition of chromium to systems calcined at 700oC and 1000oC led to a decrease in the breakdown electric field, with the exception of the systems 99.5% +0.5% Sb2O3 + 0.5% Co3O4 e 99.5% +0.5% Sb2O3 + 0.5% Co3O4 (excess) + 0.05% Cr2O3 (excess), where there was a decrease of breakdown electric field with the addition of chromium, and this can be explained because of their densities. All samples calcined at 1200oC regardless of the composition, showed very similar microstructure, high porosity and small grain size. The sample that presented the best varistor behavior with the lower leakage current was the FCC25% (75% of varistor formulation, 99,4%SnO2. 0,5%Co3O4. 0,05%Nb2O5. 0,05%Cr2O3 and 25% of conductive formulation, 99,0%SnO2. 0,5%Co3O4. 0,5%Sb2O3).
Neste trabalho estudou-se sistematicamente a substituição do Nb2O5 por Sb2O3 na composição de um sistema varistor ternário e estudo da calcinação de sistemas binários e multicomponentes e sua relação microestruturapropriedade elétricas. Na Parte I do trabalho, estudo da substituição do Nb2O5 por Sb2O3, as composições foram preparadas via processamento cerâmico convencional e secadas via “spray-dryer”. A conformação foi realizada a 25 MPa e a sinterização foi realizada a 1350C por 2 horas. Com o aumento da concentração de Sb2O3 o comportamento não linear da cerâmica foi reduzido, acompanhado da redução do campo elétrico de ruptura e aumento da corrente de fuga. Com o aumenta da concentração de Sb2O3 de 0,05% para 0,5% em mol, as amostras apresentaram-se mais porosas, sugerindo que concentrações mais elevadas de Sb2O3 diminuem a taxa de sinterização. Esta diminuição foi associada ao aumento da concentração de vacâncias de estanho que conduz a processos não densificantes. Na parte II, estudou-se a influência da calcinação (700oC, 1000oC e 1200oC) de sistemas binários e multicomponentes. As composições foram preparadas pelo método convencional, com a adição do processo de calcinação. As amostras foram conformadas a 75 MPa e sinterizados a 1300oC para os sistemas calcinados a 1200OC e 1300OC e 1350OC por 2 horas para os sistemas calcinados a 700OC e 1000OC. Alguns sistemas estudados apresentaram a fase cassiterita associada a fase SnO. Com a adição de dopantes ocorreu um aumento na densidade dos sistemas e o aumento da temperatura de sinterização também levou a um leve aumento na densidade. A adição de cromo aos sistemas calcinados a 700OC e 1000OC levou a uma diminuição do campo elétrico de ruptura, com exceção dos sistemas, 9,5%+0,5%Sb2O3 + 0,5% Co3O4 e 99,5%+0,5%Sb2O3 + 0,5% Co3O4 (excesso) + 0,05% Cr2O3 (excesso), onde ocorreu a diminuição do campo elétrico de ruptura com a adição de cromo, podendo isto ser explicado através de suas densidades. Todas as amostras calcinadas a 1200oC, independentemente da composição, apresentaram microestrutura muito semelhantes, apresentaram alta porosidade e pequeno tamanho de grão. A amostra que apresentou o melhor comportamento varistor, com menor corrente de fuga foi a FCC25% (75% da formulação varistora, 99,4%SnO2.0,5%Co3O4. 0,05%Nb2O5.0,05%Cr2O3 e 25% da formulação condutora, 99,0%SnO2. 0,5%Co3O4. 0,5%Sb2O3).
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Arsat, Rashidah, and rashidah arsat@student rmit edu au. "Investigation of Nanostructured Thin Films on Surface Acoustic Wave and Conductometric Transducers for Gas Sensing Applications." RMIT University. Electrical and Computer Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091002.094407.
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In this thesis, the author proposed and developed nanostructured materials based Surface Acoustic Wave (SAW) and conductometric transducers for gas sensing applications. The device fabrication, nanostructured materials synthesis and characterization, as well as their gas sensing performance have been undertaken. The investigated structures are based on two structures: lithium niobate (LiNbO3) and lithium tantalate (LiTaO3). These two substrates were chosen for their high electromechanical coupling coefficient. The conductometric structure is based on langasite (LGS) substrate. LGS was selected because it does not exhibit any phase transition up to its melting point (1470°C). Four types of nanostructured materials were investigated as gas sensing layers, they are: polyaniline, polyvinylpyrrolidone (PVP), graphene and antimony oxide (Sb2O3). The developed nanostructured materials based sensors have high surface to volume ratio, resulting in high sensitivity towards di¤erent gas species. Several synthesis methods were conducted to deposit nanostructured materials on the whole area of SAW based and conductometric transducers. Electropolymerization method was used to synthesize and deposit polyaniline nanofibers on 36° YX LiTaO3 and 64° YX LiNbO3 SAW substrates. By varying several parameters during electropolymerization, the effect on gas sensing properties were investigated. The author also extended her research to successfully develop polyaniline/inorganic nanocomposites based SAW structures for room temperature gas sensing applications. Via electrospinning method, PVP fibres and its composites were successfully deposited on 36° YX LiTaO3 SAW transducers. Again in this method, the author varied several parameters of electrospinning such as distance and concentration, and investigated the effect on gas sensing performance. Graphene-like nano-sheets were synthesized on 36° YX LiTaO3 SAW devices. This material was synthesized by spin-coating graphite oxide (GO) on the substrate and then exposin g the GO to hydrazine to reduce it to graphene. X-ray photoelectron spectroscopy (XPS) and Raman characterizations showed that the reduced GO was not an ideal graphene. This information was required to understand the properties of the deposited graphene and link its properties to the gas sensing properties. Thermal evaporation method was used to grow Sb2O3 nanostructures on LGS conductometric transducers. Using this method, different nanoscale structures such as nanorods and lobe-like shapes were found on the gold interdigitated transducers (IDTs) and LGS substrate. The gas sensing performance of the deposited nanostructured Sb2O3 based LGS conductometric sensors was investigated at elevated temperatures. The gas sensing performance of the investigated nanostructured materials/SAW and conductometric structures provide a way for further investigation to future commerciallization of these types of sensors.
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Goedel, Karl Christoph. "Optoelectronic applications of solution-processable sulfide semiconductors." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/268085.
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Solar cells and photodetectors rely on similar physical principles based on the interaction of light and matter. Both types of optoelectronic devices are indispensable in a wide range of technological applications, from large-scale renewable power conversion to everyday consumer items. In this thesis, the use of facile solution-processable semiconductors in solar cells and light sensors is studied with a focus on antimony sulfide (Sb₂S₃) and antimony sulfoiodide (SbSI). The improvement of the photovoltaic performance in Sb₂S₃ sensitized solar cells upon the controlled partial oxidation of the absorber layer is investigated. A reduction in charge carrier recombination is the reason for the improved efficiency, caused by the oxidation process. Further, a new chemical bath deposition method for antimony sulfide is developed. Carried out at room temperature, this technique eliminates the necessity of cooling equipment during the deposition process. The antimony sulfide from this method decreases the density of trap states compared to the conventional deposition. Power-conversion efficiencies of up to η=5.1% are achieved in antimony sulfide sensitised solar cells using the new room temperature deposition method. Finally, antimony sulfide is used as a precursor to form films of antimony sulfoiodide (SbSI) micro-crystals in a facile physical vapour process. These films are then used to fabricate photodetectors. With PMMA as an insulating spacer layer, the devices are built in a sandwich-type architecture. Optoelectronic characterisation shows that these devices have the shortest response and recovery times reported for SbSI photodetectors to date.
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Nowka, Christian [Verfasser], Bernd [Akademischer Betreuer] [Gutachter] Büchner, and Jörg [Gutachter] Feller. "Untersuchungen zu Gasphasentransporten in quasibinären Systemen von Bi2Se3 mit Bi2Te3, Sb2Se3, MnSe und FeSe zur Erzeugung von Nanokristallen / Christian Nowka ; Gutachter: Bernd Büchner, Jörg Feller ; Betreuer: Bernd Büchner." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/112393178X/34.
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Ribeiro, Emerson Schwingel. "Oxido misto SiO2/Sb2O3 : estudo da tecnica de preparação, caracteristicas, propriedades e aplicações do material obtido." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249676.
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Orientador: Yoshitaka GushikemTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Doutorado
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Kautto, Per. "Influences of palladium ceramics on valuable metal losses to a PbO-SiO2-Sb2O3 based silver smelting slag." Thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81308.
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Silver and palladium can be found in the so called palladium-ceramics which comes from catalyst production. These valuable metals needs to be recovered from these wastes in order to further increase both the environmental and economic sustainability of our society. This material has also been suspected of causing some problems at Boliden’s smelter Rönnskär during the silver smelting. Unfortunately due to the nature of massive economics at work in precious metal production there has not been much published work around this subject. Therefore this works seeks to increase the understanding of how this waste affects the A-slag in the precious metal production at Rönnskär. This work takes a look at how certain fluxes and temperatures affects the slag and metal phases, as well as how increasing the addition of the palladium-ceramic affects the melt. It does so by making screening tests with a basic setup of slag from the process, silver granules and additions of coke and sodium carbonate at different temperatures. The results show that using a reducing environment by adding coke does increase the recovery of the precious metals. Increasing the temperature of the melt also shows an improvement in the recovery of the precious metals. Furthermore the basis to an alternative way of using this material, consisting of smelting it together with silver and fluxing materials has been suggested in this work in order to eliminate the possible problems it causes in the current process.Silver och palladium kan finnas i materialet som kallas katalysatormassa som kommer från framställningen av katalysatorer. Dessa värdefulla metaller måste återvinnas från detta avfall för att öka hållbarheten i vårt samhälle både miljömässigt och ekonomiskt. Materialet har också varit en möjlig orsak till problem vid silversmältningen på Bolidens smältverk, Rönnskär. Tyvärr på grund av den enorma ekonomin kring ädelmetaller och deras produktion har det inte publicerats många artiklar om detta ämne. Därför försöker detta arbete att öka förståelsen av hur detta avfall påverkar A-slaggen hos ädelmetallframställningen på Rönnskär. Detta arbete undersöker på hur olika flussmedel och temperaturer påverkar slaggen och metallfasen, samt hur en ökad mängd katalysatormassa påverkar smältan. Det görs genom att göra flera testsmältor med en bas med slagg från processen, silvergranuler samt tillsatser av koks eller natriumkarbonat vid olika temperaturer. Resultaten visar att användandet av en reducerande miljö genom tillsättningen av koks ökar återvinningen av ädelmetallerna. En ökad temperatur på smältan har också visat på en ökad återvinning. Utöver detta så har grunden till ett alternativt sätt att använda sig av materialet tagits fram. Detta alternativ består av att smälta materialet tillsammans med silver och flussmedel och har tagits fram för att undvika möjliga problem i befintlig process.
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Machado, Tamires Martinhão. "Estudo de vidros de teluritos contendo Sb2O3 para obtenção de nanopartículas de cobre com aplicação em fotônica." Universidade Federal de Juiz de Fora (UFJF), 2018. https://repositorio.ufjf.br/jspui/handle/ufjf/7175.
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Vidros transparentes do sistema vítreo 0.95TeO2-(0.05-x)Sb2O3–xCuO contendo nanopartículas de cobre foi preparado com sucesso pelo método convencional de fusão – resfriamento dos materiais precursores, utilizando a rota redox do óxido de antimônio. Esta técnica de preparação de vidros permite a produção de nanopartículas metálicas durante a fusão dos materiais, através da reação de oxidação Sb3+ → Sb5+ + 2e-, que permite a redução de íons metálicos. A investigação estrutural foi realizada por calorimetria exploratória diferencial (DSC), difração de raios X (DRX) e espectroscopia Raman. Imagens de microscopia eletrônica de transmissão (TEM) e espectroscopia UV-visível evidenciaram a formação de clusters de nanopartículas de cobre cúbicas, distribuídas aleatoriamente em meio a matriz vítrea. A eficácia dos efeitos plasmônicos das nanopartículas de cobre promoveu a intensificação da fluorescência dos íons érbio. A interação da radiação excitante e amostra levou ao processo de excitação térmica, promovendo o aumento da população de níveis de energia específicos dos íons érbio, com consequente resposta óptica, evidenciada pela estrutura vibrônica presente no espectro de fluorescência dos vidros de teluritos contendo nanopartículas de cobre dopados com íons érbio. Além disso, os efeitos plasmônicos das nanopartículas de cobre na intensificação das emissões no infravermelho e conversão ascendente nos vidros de teluritos co-dopados com íons Yb3+/Ce3+/Er3+ sob excitação em 980 nm também foram investigados. As contribuições dos íons Yb3+ e Ce3+ também foram discutidas. A eficiência da ressonância do plasmon de superfície localizado (LSPR) das nanopartículas de cobre promoveu um melhoramento de cerca de 47% da emissão em 1550 nm dos íons Er3+. Além disso, o tempo de decaimento da transição Er3+: 4I13/2 → 4I15/2 aumentou em cerca de 50% na amostra contendo nanopartículas de cobre. Finalmente, os vidros de teluritos contendo nanopartículas de cobre apresentaram resultados interessantes quando utilizados como substratos para obtenção de espectros Raman intensificados por superfície (espectros SERS), sendo obtidos satisfatoriamente espectros SERS para soluções de 2,2’-bipiridina 1,0 × 10-5 mol.L-1 e do corante azul do Nilo 1,0 × 10-7 mol.L-1.
Transparent 0.95TeO2-(0.05-x)Sb2O3-xCuO glassy system containing copper nanoparticles were successfully prepared by the conventional melt quenching method of starting materials, using the antimony oxide redox route. This technique allows the production of metallic nanoparticles during melting, through the reaction Sb3+ → Sb5++ 2e-, which leads to the reduction of metallic ions. The structural investigation was carried out by differential scanning calorimetry (DSC), X ray diffraction (XRD) and Raman spectroscopy. Transmission electron microscopy image (TEM) and UV-visible spectroscopy evidenced the formation of cubic copper nanoparticles, randomly embedded in the glassy matrix. The effectiveness of the plasmonic effects of the copper nanoparticles provided the enhancement of the fluorescence of the erbium ions. The interaction between excitant radiation and sample led to the thermal excitation, which increased the population of specific energy levels of erbium ions, with consequent optical response into vibronic structure, as can be seen in the erbium-doped tellurite glasses containing copper nanoparticles. Furthermore, the plasmonic effects of the copper nanoparticles on the enhancement of the infrared and upconversion emissions intensities in the Er3+/Yb3+/Ce3+ co-doped transparent tellurite glasses under 980 nm laser diode excitation were investigated. The roles of Yb3+ and Ce3+ as sensitizers are also discussed. The effectiveness of localized surface plasmon resonance (LSPR) of the copper nanoparticles provided an improvement about 47% of the 1550 nm luminescence intensity of the Er3+ ions. Moreover, the lifetime of the Er3+: 4I13/2 → 4I15/2 transition increased around 50 % in the copper nanoparticle containing samples. Finally, the tellurite glasses containing copper nanoparticles showed interesting results as substrates for obtainment of surface enhanced Raman spectra (SERS spectra) and SERS spectra were satisfactorily obtained for 2,2'-bipyridine 1.0 × 10 -5 mol.L-1 and Nile blue dye 1.0 × 10-7 mol.L-1 solutions.
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Eskhult, Jonas. "Electrochemical Deposition of Nanostructured Metal/Metal-Oxide Coatings." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8186.
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Silva, Dilleys Ferreira da. "Estudo dos efeitos fotoinduzidos por Raio-X em filmes vítreos do sistema [Sb(PO3)3]n-Sb2O3 dopados com CuO." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-29032010-150508/.
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A fotosensibilidade à radiação dos vidros fosfatos é uma propriedade que tem despertado grande interesse nas últimas décadas12. No presente trabalho, foi realizado um estudo sistemático e comparativo dos fenômenos fotoinduzidos por meio da caracterização de filmes do sistema (Sb(PO3)3)n - Sb2O3 quando dopados com óxido de cobre (CuO). Neste estudo, foram observadas as mudanças fotoestruturais e os efeitos causados por ação dos Raios-X. Os danos causados pela radiação sobre as amostras foram investigados através de medidas de perfilometria, Difração de Raio-X, EPR (Electron Paramagnetic Resonance) e SFG (Sum Frequency Generation) para a análise morfológica dos filmes, usadas para a compreensão das mudanças estruturais ocorridas. Além disso, foram realizadas medidas de absorção UV-Vis para a determinação de suas propriedades ópticas. Estudos recentes mostraram que o sistema vítreo (Sb(PO3)3)n - Sb2O3 sofre efeito de fotoclareamento e fotocontração, devido a irradiação com laser UV16. Nossos resultados mostraram que filmes do mesmo sistema vítreo dopados com 3%CuO, quando irradiados com Raio-X, apresentam efeito de fotoescurecimento, que foi observado visivelmente, e fotoexpansão, que foi confirmado por medidas de perfilometria. Ambos os efeitos, fotoescurecimento e fotoexpansão, ocorrem simultaneamente nos filmes irradiados e tem uma evidente dependência com a variação de parâmetros como espessura do filme e tempo de exposição à radiaçãoThe photosensibility to radiation of phosphate glasses is a property that has attracted great interest in the last decades12. In this work, we realized a systematic and comparative study of the photoinduced phenomena through characterization of the doped copper oxide (CuO) (Sb(PO3)3)n-Sb2O3 system films. In this study, we observed the photostructural changes and the effects caused by X-ray. The radiation damage on the samples was investigated by measurements of profilometry, X-ray diffraction, EPR (Electron Paramagnetic Resonance) and SFG (Sum Frequency Generation) for morphological analysis, used for the understanding of the structural changes occurred. Besides that, we realized UV-Vis absorption measurements for the determination of its optical properties. Recents studies have shown the (Sb(PO3)3)n-Sb2O3 glassy system has photobleaching and photocontraction effects, when irradiated with UV laser16. Our results have shown that films of the same glassy system doped with 3%CuO, when irradiated with X-ray, show the photodarkening effect, which was visually observed, and photoexpansion, which was confirmed by profilometry measurements. Both effects, photodarkening and photoexpansion, occur simultaneously in the irradiated films and have a evident dependence with the parameters changes, as film thickness and radiation exposure time.
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Chen, Jing-Wei, and 陳敬薇. "Sb/Co, Co/Sb2Te3 and Ni/Sb2Te3 interfacial reactions and electromigration effects upon interfacial reactions." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8925z4.
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HSIN-YUCHEN and 陳信宇. "Edge State of Monolayer Antimonene on Sb2Te3." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/b6388w.
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Wang, Sheng-Yu, and 王晟宇. "Fabrication and Characterization of Thermoelectric Bi2Te3-Sb2Te3 Nanowire." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/26874802973992075210.
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碩士國立臺灣海洋大學
電機工程學系
96
Bi2Te3 and Sb2Te3 employed in this research have better figure-of-merit under room temperature conditions. The material is therefore suited for the application of uncooled thermopile infrared detectors. In the experiment, the detector is completed through the processes of AAO nanopore array farication, electrochemical deposition of material within nanopores, and finally measuring the signals through the top and bottom electrode. Pertaining to the analysis of Sb2Te3 and Bi2Te3, electrochemical method is first used to deposit the material into the AAO nanopores; the material composition is then confirmed with XRD and EDS analysis followed by surface observation with SEM; further, resistance variation behavior corresponding to temperature change is determined with PPMS and four point probe measurement; and finally is the determination of thermoelectric coefficient with a Seebeck measurement system. Comparing the results before and after annealing, it is found that Bi2Te3 has better characteristics after annealing for 2 hours at 250℃ and Sb2Te3 is better after annealing for 2 hours at 120℃. Thus, these are adopted in the fabrication of detector components; their thermoelectric coefficient is 67.7 μV/K for Bi2Te3 and 100 μV/K for Sb2Te3. The completed detector component is placed in to a aluminum container, and the characteristics measured by altering conditions; the experimental results confirm the acquired signals accords with thermal effect mechanism. Using thermopile detector produce from the serial assembly of Sb2Te3 and Bi2Te3 as an example and with an operating temperature of 300K and chopper frequency within 0.2~50Hz, the responsivity has a maximum of 23.12 V/W at 1Hz and decreases beyond 1Hz. From the foregoing result and the noise voltage measured, a normalized detectivity maximum of 16.732x104 cmHz1/2W-1 at 1Hz is deduced, and beyond this frequency the detectivity decreases .
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She, Kun-dian, and 佘坤典. "Design and Fabrication of Bi2Te3/Sb2Te3 Micro TE-cooler." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/3g847r.
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碩士國立中山大學
電機工程學系研究所
95
This paper presents an integrated column-type micro thermoelectric cooler (μ-TEC) constructed with serial connected p-type antimony-tellurium (Sb2Te3) and n-type bismuth-tellurium (Bi2Te3) micro pillars deposited by electrochemical deposited technology. To optimize the power factor, density and uniformity of the TE films and to enhance the reproducibility of μ-TEC device, a cathode with tunable rotary speed and with accurate current controller has been designed in the electroplating system of this research. The electroplating deposited Bi2Te3 and Sb2Te3 with an average thickness of 8 μm, are connected using Cr/Au layers at the hot junctions and cold junctions. The measured Seebeck coefficient and electrical resistivity are -86 μV/K and 16 μΩ-m for Bi2Te3 films after annealed at 250°C, and are 68 μV/K and 30 μΩ-m for Sb2Te3 films after annealed at 200°C. The optimized power factors of the n-type (2.64×10-4 W/K2m) and p-type (2.64×10-4 W/K2m) telluride compounds have been demonstrated in this paper. Under 5 volts driven, the integrated μ-TEC device shows average cooling achieved is about 1.3 °C.
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Cheng, Wei-Jen, and 陳威任. "A Study of Thermoelectric Properties of Bi2Te3/Sb2Te3 Thin Films." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/71146512365041809488.
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碩士國立中正大學
光機電整合工程所
96
The inorganic thermoelectric thin films were fabricated by high vacuum evaporator system on transparent and conductive ITO substrates . In addition, post-annealing of the films was performed using a rapid thermal processing system. Finally, we discussed with the thermoelectric properties. In this investigation, we used P-type Sb、Te and N-Type Bi、Te those four kinds of thermoelectric materials. Then, we change the different evaporation rate and keep film thickness were 5000Å. In this study, we discussed with the effect of thermoelectric properties of the inorganic thermoelectric thin films P-Type Sb2Te3 and N-Type Bi2Te3 after three kinds of rapid thermal processing system temperature. Evidence showed that when evaporation rate were(Bi：Te)( 1 ： 1.5), the element rate were approach P-Type Sb2Te3 and N-Type Bi2Te3 thin films and the thermoelectric properties were the best. Finally, we demonstrated that after rapid thermal processing system can make the thermoelectric thin films has more crystals. Therefore, Seebeck coefficient and power factor were also increased.
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Ming-YuLin and 林明昱. "The growth, structure and electronic property of Se-doped Sb2Te3." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89101128748231738713.
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Krishnan, Mandayam Gomatam. "Electronic structure calculations of Bi2Te3/Sb2Te3 superlattices for thermoelectric applications." 2008. http://www.lib.ncsu.edu/theses/available/etd-11052008-161838/unrestricted/etd.pdf.
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Juan, Chien-Chang, and 阮建彰. "Preparation and Thermoelectric Properties of (Bi2Te3)x/(Sb2Te3)1-x Composites." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/yw96f2.
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碩士國立東華大學
材料科學與工程學系
102
In this study, Sb2Te3 was selected as a matrix material and a semiconductor material Bi2Te3 with lower energy gap was incorporated to form microstructures in it. For this purpose, the composites (Bi2Te3¬)x/ (Sb2Te3)1-x ,with x=0 , 0.1 , 0.2 , 0.3 were prepared by powder metallurgy. The melting point of Bi2Te3 is lower then that of Sb2Te3. As Bi2Te3 and Sb2Te3 powders were mixed homogeneously and hot-pressed at a temperature slightly above the melting point of Bi2Te3, liquidized Bi2Te3 may diffuse between Sb2Te3 solid and form approximately the nano-scale microstructure in the matrices. The composition and microstructure of these two-component composites were examined by X-ray and FE-SEM. Thermoelectric properties including Seebeck coefficient, electric resistivity, and thermal conductivity were measured from 150 K to 400K. XRD and FE-SEM analysis show that :SbBiTe ternary compounds exist in all the samples of these as-prepared composites. The resistivity of composites were increased with increasing temperature. Resistance was significantly decreased when Bi2Te3 adding. The Seebeck coefficient of all samples was increased in the temperature range studied. The study shows that the p-type carriers dominate the thermoelectric transport. The figure of merit (ZT) for these composites was evaluated and discussed. The maximum ZT is 0.0295 for (Bi2Te3¬)0.1/ (Sb2Te3)0.9 at 400K.
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Po-ShiungWang and 王柏雄. "Study of Sb2Te3 and Alloy Films by Thermoelectric Grown on Glass." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/38588753727580950715.
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Chen, Yi Cheng, and 陳奕成. "Study of Terahertz Emission Spectroscopy in Topological Insulator Sb2Te3 thin film." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/00698767289598710294.
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碩士國立交通大學
電子物理系所
104
In this thesis, we show the helicity-dependent terahertz emissions from topological insulator (TI) Sb2Te3 thin films by ultrafast optical excitation. We observed the polarity-reversal of the emitted THz radiation as the helicity of optical pulses reverses. The observed phenomenon is consistent with the characteristics of the helicity-dependent photocurrent on TIs. Employing a decomposition-recombination procedure in time domain, the individual contributions of circular photogalvanic effect, linear photogalvanic effect and photon drag effect are revealed completely. Additionally, based on the Tr-ARPES results and considering transient-current radiation as well as far-field diffraction, our results are the same as that from Tr-ARPES results. Finally, our results not only demonstrate that helicity-dependent THz emission originated from topological insulator surface states can be manipulated by ultrafast optical pulses but also pave a way towards applications of THz emission spectroscopy on spintronics.
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Jia, Shao-Syuan, and 夏紹軒. "Microstructure and Thermoelectric Properties of (Sb2Te3)1-x(CdTe)x Composites." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/69445455211505194660.
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碩士國立東華大學
材料科學與工程學系
99
In this study, a series of thermoelectric materials with the compositions (Sb2Te3)1-x(CdTe)x (x = 0 – 0.15), were prepared in order to study the thermoelectric properties of the compounds with specific microstructure, i.e. the dispersion of a wider band gap CdTe second phase within a narrow band gap Sb2Te3 matrix. The compositions, phase assemblages, and microstructures of the synthesized materials were analyzed by X-ray diffraction analysis (XRD), optical microscopy (OM), field emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM). The thermoelectric properties were studied by means of thermal and electrical transport measurement in the temperature range between 40 and 420K. Whereas the synthesized materials with x = 0 – 0.05 appear to be single phase, according to XRD, SEM and TEM observations, the materials with x = 0.1 and 0.15 are two phase mixture with CdTe particles dispersed within the Sb2Te3 matrix. The average grain size of CdTe is about 1 μm. For all compositions, the Seebeck coefficient were positive in the temperature range studied, suggesting that the hole-type carriers dominate the thermoelectric transport. Resistivity of (Sb2Te3)1-x(CdTe)x composites increases with increasing temperature and the resistivity increases with increasing Cd content. The maximum figure of merit (ZT) value of 0.276 was obtained for the sample (Sb2Te3)0.99(CdTe)0.01 at 420k. Temperature and composition dependences of resistivity, Seebeck coefficient and thermal conductivity for various composition of (Sb2Te3)1-x(CdTe)x composites were discussed.
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Jian-RueiChen and 陳建睿. "Characterizations of Topological Sb2Te3/Bi2Te3 Heterostructures and the application for photodetector." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5g9c2d.
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碩士國立成功大學
光電科學與工程學系
107
In this research. We grow Sb2Te3/Bi2Te3 heterostructure on sapphire (0001) substrate by the MBE system. At the interface, diffusion of Sb and Bi causes the ternary compounds and tuning fermi level. By adjusting the thickness ,we can tuning Fermi level to the dirac point and form an ideal topological insulator. We confirmed this result through ARPES and hall measurements. In Hall measurement, carrier type transition occurs between 7/10nm and 8/10nm. The change of carrier type also appeared in ARPES measurement. At this time, Surface state replaces bulk state as the main contributor to carrier transport. On the other hand, Sb2Te3/Bi2Te3 heterostructure has a p-n junction at the interface. The built-in potential at the interface can effectively separate the electron-hole pairs in TI and suppress the rapid recombination of carriers, leading to an outstanding photo responsivity. At the same time as the carrier type changes, the largest depletion region will occur at the interface. This can effectively separate the electron-hole pairs , and lead to the maximum photo responsivity. Finally, we obtain maximum responsivity of the photodetector measured under 632.8 nm light illumination at 7/10 nm Sb2Te3/Bi2Te3. The photodetector possessed a large light responsivity of 167 A/W. The result of photodetector measurement correlates with the conclusion of Hall measurement.
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Leimkühler, Gisbert [Verfasser]. "Elektrochemische Herstellung und strukturelle Untersuchung von Sb2Te3 und SbxTey / von Gisbert Leimkühler." 2003. http://d-nb.info/969279493/34.
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Peng, Cheng-Hao, and 彭成浩. "Optimal Process of Electron Beam Evaporation of Sb2Te3 on the Glass Substrate." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/qswn6t.
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碩士國立臺北科技大學
製造科技研究所
98
This study adopts Sb2Te3 thermoelectric grains to evaporate Sb2Te3 thin films by electron beam evaporation and acquires better thermoelectric merit figure (ZT value) through different evaporation process parameters and film annealing conditions tests. ITO conductive glass is cleaned by acetone, isopropyl alcohol (IPA) and deionized water (DI water) by ultrasonic vibration and evaporated at vacuum, 5×10-6torr to obtain the optimal substrate temperature, film annealing temperature and time via different evaporation processes to make Sb2Te3 film have better resistivity (ρ), Seebeck coefficient and the highest power factor. This study uses X-ray diffraction (XRD) pattern to measure the thin film microstructure, adopts Hall measurement system to test the carrier concentration and observes the morphology of thin film surface microstructure by scanning electron microscope (SEM). Besides, Van der Pauw four-point probe is employed to measure the resistivity of thin films and 3ω method is used to test thermal conductivity of thin films. Results show that the differences of temperature will cause different sizes of Sb2Te3 grains in Sb2Te3 films and different Seebeck coefficient of thin films. When the temperature of substrate is set at 200℃and annealed at 220℃ for 60 minutes to prepare for Sb2Te3 thin films, Seebeck coefficient can increase from 87.6μV/K to 177.7μV/K, resistivity can reduce from 6.21mΩ-cm to 2.53mΩ-cm and power factor can reach the maximum – 1.24 10-3W/K2m. Moreover, above-mentioned Sb2Te3 thin films fabricated under the same evaporation and annealing conditions are tested thermal conductivity with 0.93W/mK by 3ω method and calculated ZT value –1.33(10-3).
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Chen, Wei, and 陳偉. "Investigation of the thermoelectric properties of Sb2Te3 thinfilms by thermal evaporation processes." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/3nu88f.
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碩士國立中山大學
電機工程學系研究所
101
The crisis of energy shortage and carbon reduction has become an important issue; the green technology is getting more and more attention. The thermoelectric materials exhibit the advantages of environmental protection and renewable energy. The thermoelectric devices can convert heat energy to electric energy and vice versa. Bismuth telluride and antimony telluride are known to be the best thermoelectric materials within the room temperature region. In this study, the Sb2Te3 thin films were prepared by thermal evaporation method, and the thermoelectric properties were promoted by heating and annealing processes. Further, in order to improve the power factor of the thin films, Ag-doped Sb2Te3 has been studied by co-evaporation. The structures of the thin films were analyzed by XRD and SEM respectively. The thin films deposited at room temperature exists many defects, poor crystallization, and amorphous phase. Therefore, the conductivity was lower. The chemical composition of the thin films can be obtained from EDS analysis. The ratio of Sb to Te is 48.5：51.5 for the thin films deposited at room temperature, whereas it tends to be 40：60 as the substrate temperature increases. The grain size and X-ray diffraction peaks were increased by the increased temperature. The process of annealing could effectively reduce the defects and enhance the diffraction peaks. According to the measurement results, the Seebeck coefficient was decreased by the increased annealing temperature. With increase of Ag doping content, the Seebeck coefficient will be decreased, by the increased annealing temperature . On the other hand, the conductivity was increased with increase the substrate temperatures. Then, the conductivity was increased substantially with Ag doping. Further, the conductivity was increased as the annealing temperature increased. The optimal conductivity of 1.27×10¬3 (S․cm-1) was obtained as the thin films were deposited at the substrate temperature of 150°C and annealed at 300°C. The conductivity of the above thin film was increased to 2.25×10¬3 (S․cm-1) after 2.11 atom% Ag doping and annealed at 200°C, whereas the Seebeck coefficient was reduced to 94.2 (µV/K). The maximum power factor of 19.99 (µW/cm․K2) was obtained.
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Cheng, Hsueh Wen, and 鄭學文. "The Effects of Small Additions Elements on Properties of Sb2Te3 Thermoelectric Materials." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/90351990996890892709.
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碩士高苑科技大學
電子工程研究所
100
Thermoelectric materials is a function of electricity and thermal energy conversion materials, thermoelectric equipment has the advantage of no vibration, no noise, small size, light weight, durable, non-polluting substances, have become the people to study energy materials.The efficiency of thermoelectric conversion is evaluated by means of the thermoelectric figure of merit (ZT). The dimensionless ZT is defined as ZT =α2σT / κ, where α is the Seebeck coefficient, α= ΔV/ΔT, σ is the conductivity of the materials, κ is the thermal conductivity, and T is the absolute temperature. Therefore, the good thermoelectric materials should have a large value of α, a large electrical conductivity, and thermal conductivity. In this study, the medium temperature thermoelectric materials were prepared using the vacuum melting method. We have prepared a series of samples with composition Sb35Te60X5, X: Ag, Zn, and Si. Study the effects of a small amount of elements on properties of the Sb35Te60X5, such as electrical resistivity, the Seebeck coefficient, power factor. The experimental results show that the resistivity of Sb2Te3 is about 12.91 x10-3Ω • m, the Seebeck coefficient is about 50 x10-4V/K and the power factor is 1.936 x10-3WK-2m-1. Adding Ag, Zn, and Si elements can enhance the electrical resistivity of the Sb2Te3 alloys, as well as to reduce the Seebeck coefficient and power factor. The addition of Si of the Sb35Te60Si5thermoelectric materials is only slightly enhance the resistance was 15.9x10-3Ω • m. Add of Ag, Zn, Si to Sb2Te3 alloy will reduce the its Beaker coefficient, add Zn and Si only slightly lower Beaker coefficientThe power factor for the pure Sb2Te3 alloy 1.936x x10-3WK-2m-1, add the Si of Sb35Te60Si5 thermoelectric materials, the power factor of 1.006x x10-3WK-2m-1, about 0.52 of the power factor of the pure Sb2Te3 alloy. From the above that add Ag, Zn and Si into the Sb2Te3 thermoelectric material, did not significantly improve its thermoelectric properties
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Lin, Yu-Hsuan, and 林雨萱. "The characterization of prepared thermoelectric materials Sb2Te3 and Bi2Te3 by electrochemical deposition." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/89906465566064125463.
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碩士國立聯合大學
化學工程學系碩士班
99
Bismuth telluride、antimony telluride and their derivative compounds are narrow band-gap semiconductors with good thermo- electric characteristics at room temperature . Their thermoelectric nature depends on their composition . Bi2Te3 and Sb2Te3 are widely used for biomedical、 thermoelectric、optoelectronic fields and solar cell and so on . In this paper , we change different parameters (temperature、composition of solution、 stirring) to codeposit thermoelectric powders by electro- chemical deposition (ECD) in aqueous systems . We can known the electrochemical behavior of the binary alloy Bi/Te and Sb/Te is known by cyclic voltametry . HTeO2 + in tartaric acid, there are two reduction peaks,This means that Te has two reduction mechanisms by cyclic voltammogram . We use SEM、EDS、XRD to analyze the morphology、composition and know that the crystalline phases of BixTey and SbxTey are in the (0 1 5) preferred orientation having a good surface . Finally,we use the instrument CHI-440 (EQCM) to analyze electrochemical deposition mechanism after adding tartaric acid as a chelating agent for progressive nucleation mechanism, while for instaneous mechanism without tartaric acid. Electrochemical performance efficiency is about 78%.