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Structural, chemical, and thermoelectric properties of Bi{sub 2}Te{sub 3} Peltier materials. Bulk, thin films, and superlattices

Abstract

In this work, the nature of the natural nanostructure (nns) was analysed and the correlations to the transport coefficients, particularly the lattice thermal conductivity, is discussed. Experimental methods are presented for the first time, yielding an accurate quantitative analysis of the chemical composition and of stress fields in Bi{sub 2}Te{sub 3} and in compounds with similar structural and chemical microstructures. This work can be subdivided as follows: (I) N-type Bi{sub 2}(Te{sub 0.91}Se{sub 0.09}){sub 3} and p-type (Bi{sub 0.26}Sb{sub 0.74}){sub 1.98}(Te{sub 0.99}Se{sub 0.01}){sub 3.02} bulk materials synthesised by the Bridgman technique. (II) Bi{sub 2}Te{sub 3} thin films and Bi{sub 2}Te{sub 3}/Bi{sub 2}(Te{sub 0.88}Se{sub 0.12}){sub 3} superlattices epitaxially grown by molecular beam epitaxy (MBE) on BaF{sub 2} substrates with periods of {delta}-12 nm at the Fraunhofer-Institut fuer Physikalische Messtechnik (IPM). (III) Experimental methods, i.e., TEM specimen preparation, high-accuracy quantitative chemical analysis by EDX in the TEM, and image simulations of dislocations and the nns according to the two-beam dynamical diffraction theory. The nns was analysed in detail by stereomicroscopy and by image simulation and was found to be a pure sinusoidal displacement field with (i) a displacement vector parallel to <5,-5,1> and an amplitude of about 10 pm and (ii) a wave  More>>
Authors:
Publication Date:
Jul 01, 2008
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-0539
Resource Relation:
Other Information: TH: Diss. (Dr.rer.nat.)
Subject:
36 MATERIALS SCIENCE; THERMOELECTRIC PROPERTIES; THIN FILMS; SUPERLATTICES; NANOSTRUCTURES; THERMAL CONDUCTIVITY; CHEMICAL COMPOSITION; STRESSES; MICROSTRUCTURE; MOLECULAR BEAM EPITAXY; SUBSTRATES; DISLOCATIONS; THERMOELECTRIC MATERIALS; TRANSMISSION ELECTRON MICROSCOPY; BISMUTH TELLURIDES; N-TYPE CONDUCTORS; BISMUTH SELENIDES; P-TYPE CONDUCTORS; ANTIMONY TELLURIDES; ANTIMONY SELENIDES; BARIUM FLUORIDES; X-RAY SPECTRA; ENERGY SPECTRA; EXPERIMENTAL DATA; BRIDGMAN METHOD
OSTI ID:
21134938
Research Organizations:
Tuebingen Univ. (Germany). Fakultaet fuer Mathematik und Physik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE09F0920
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21134938
Submitting Site:
DEN
Size:
158 pages
Announcement Date:
Mar 06, 2009

Citation Formats

Peranio, Nicola. Structural, chemical, and thermoelectric properties of Bi{sub 2}Te{sub 3} Peltier materials. Bulk, thin films, and superlattices. Germany: N. p., 2008. Web.
Peranio, Nicola. Structural, chemical, and thermoelectric properties of Bi{sub 2}Te{sub 3} Peltier materials. Bulk, thin films, and superlattices. Germany.
Peranio, Nicola. 2008. "Structural, chemical, and thermoelectric properties of Bi{sub 2}Te{sub 3} Peltier materials. Bulk, thin films, and superlattices." Germany.
@misc{etde_21134938,
title = {Structural, chemical, and thermoelectric properties of Bi{sub 2}Te{sub 3} Peltier materials. Bulk, thin films, and superlattices}
author = {Peranio, Nicola}
abstractNote = {In this work, the nature of the natural nanostructure (nns) was analysed and the correlations to the transport coefficients, particularly the lattice thermal conductivity, is discussed. Experimental methods are presented for the first time, yielding an accurate quantitative analysis of the chemical composition and of stress fields in Bi{sub 2}Te{sub 3} and in compounds with similar structural and chemical microstructures. This work can be subdivided as follows: (I) N-type Bi{sub 2}(Te{sub 0.91}Se{sub 0.09}){sub 3} and p-type (Bi{sub 0.26}Sb{sub 0.74}){sub 1.98}(Te{sub 0.99}Se{sub 0.01}){sub 3.02} bulk materials synthesised by the Bridgman technique. (II) Bi{sub 2}Te{sub 3} thin films and Bi{sub 2}Te{sub 3}/Bi{sub 2}(Te{sub 0.88}Se{sub 0.12}){sub 3} superlattices epitaxially grown by molecular beam epitaxy (MBE) on BaF{sub 2} substrates with periods of {delta}-12 nm at the Fraunhofer-Institut fuer Physikalische Messtechnik (IPM). (III) Experimental methods, i.e., TEM specimen preparation, high-accuracy quantitative chemical analysis by EDX in the TEM, and image simulations of dislocations and the nns according to the two-beam dynamical diffraction theory. The nns was analysed in detail by stereomicroscopy and by image simulation and was found to be a pure sinusoidal displacement field with (i) a displacement vector parallel to <5,-5,1> and an amplitude of about 10 pm and (ii) a wave vector parallel to {l_brace}1,0,10{r_brace} and a wavelength of 10 nm. The results obtained here showed a significant amount of stress in the samples, induced by the nns which was still not noticed and identified. Both kinds of nanostructures, artificial (ans) and natural (nns) nanostructures, yielded in thermoelectric materials a low lattice thermal conductivity which was beneficial for the thermoelectric figure of merit ZT. (orig.)}
place = {Germany}
year = {2008}
month = {Jul}
}