Nanostructured thermoelectrics: Bi2Te3 / Sb2Te3 based superlattice systems fabricated by MBE and sputtering

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dc.contributor.advisor Eibl, Oliver (Prof. Dr.) Winkler, Markus 2015-02-26T13:13:55Z 2015-02-26T13:13:55Z 2015-02
dc.identifier.other 426789903 de_DE
dc.identifier.uri de_DE
dc.description.abstract Thermoelectric materials yield mutual conversion of thermal to electrical energy by the Seebeck and Peltier effect. Synthesis of thermoelectric materials with high energy conversion efficiencies is a challenge for decades since transport properties are inversely interrelated. For this, semiconducting materials with optimized charge carrier concentration and thus Seebeck coefficients and electrical conductivities, high charge carrier mobilities, and low thermal conductivities are required. It has been proposed to overcome the unfavourable interrelations between the transport properties and increase efficiencies by introducing superlattice (SL) structures in thin films, making use of electron quantum confinement effects and phonon scattering. The aim of this work was to facilitate the fabrication of high-efficiency Bi2Te3-based thin films and SLs for room temperature applications, using new synthesis routes. Besides Molecular Beam Epitaxy growth on hot substrates, the nanoalloying method was applied, which allows to avoid re-evaporation of the volatile Te and thus control over chemical chemical composition and charge carrier concentration. For this thin element films were deposited by sputtering or evaporation on a cold substrate and annealed ex-situ, yielding the desired Bi2Te3-related compound. In addition, the nanoalloying method allowed to control texture in this highly anisotropic rhombohedral layered material without using substrates with epitaxial relation to the films. Transport properties, chemical composition and texture were measured and correlated for optimizing synthesis parameters. The nanoalloying synthesis method yielded Bi2Te3 - related thin films and SLs with controlled texture and chemical composition and improved efficiencies beyond bulk material’s efficiencies. The films were strongly c-oriented, providing enhanced stability of the SL structures against interdiffusion. en
dc.language.iso en de_DE
dc.publisher Universität Tübingen de_DE
dc.rights ubt-podok de_DE
dc.rights.uri de_DE
dc.rights.uri en
dc.subject.classification Übergitter , Energy Harvesting , Sputtern , Molekularstrahlepitaxie , Charakterisierung , Seebeck-Koeffizient , Wärmeleitfähigkeit , Elektrische Leitfähigkeit , Röntgenstrukturanalyse , Durchstrahlungselektronenmikroskopie , Rasterelektronenmikroskopie , Schicht , Beschichtung , Element , Reaktion de_DE
dc.subject.ddc 333.7 de_DE
dc.subject.ddc 500 de_DE
dc.subject.ddc 530 de_DE
dc.subject.ddc 540 de_DE
dc.subject.ddc 600 de_DE
dc.subject.ddc 620 de_DE
dc.subject.other Superlattices en
dc.subject.other Sputtering en
dc.subject.other Molecular Beam Epitaxy en
dc.subject.other Bismuth-Tellurid de_DE
dc.subject.other Antimon-Tellurid de_DE
dc.subject.other Characterization en
dc.subject.other Thermoelektrik de_DE
dc.subject.other Seebeck Coefficient en
dc.subject.other Dünne Schichten de_DE
dc.subject.other Thermal conductivity en
dc.subject.other Electrical conductivity en
dc.subject.other Dünnschichtsysteme de_DE
dc.subject.other Thermoelectrics en
dc.subject.other Power-Faktor de_DE
dc.subject.other Bismuth Telluride en
dc.subject.other Thermoelektrische Gütezahl de_DE
dc.subject.other Antimony Telluride en
dc.subject.other ZT de_DE
dc.subject.other Thin Films en
dc.subject.other Sb2Te3 de_DE
dc.subject.other Thin Film Systems en
dc.subject.other Bi2Te3 de_DE
dc.subject.other Multilayer en
dc.subject.other Power Factor en
dc.subject.other Figure of Merit en
dc.subject.other Nanoalloying en
dc.subject.other Reaction en
dc.title Nanostructured thermoelectrics: Bi2Te3 / Sb2Te3 based superlattice systems fabricated by MBE and sputtering en
dc.type PhDThesis de_DE
dcterms.dateAccepted 2015-01-29
utue.publikation.fachbereich Physik de_DE
utue.publikation.fakultaet 7 Mathematisch-Naturwissenschaftliche Fakultät de_DE


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