Texture of Electroplated Coatings of Copper and Bismuth Telluride

Chaouni, H.; Magri, Pierre; Bessières, J.; Boulanger, C.; Heizmann, J.J.

doi:10.4028/www.scientific.net/msf.157-162.1371

Cited by 4 publications

(8 citation statements)

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“…According to the standard ICDD PDF card (08-0021), all of the detected peaks are indexed as those from the rhombohedral Bi 2 Te 3 crystal (space group (R3̄ m) (166)) with hexagonal crystal structures. However, the intensity ratios of the peaks are not in good agreement with those obtained by XRD on a ground product, indicating an orientational effect in the film growth . The average crystallite size of electrodeposited bismuth telluride calculated by Scherrer's equation is in the range between 10 and 30 nm, which is consistent with the result from SEM as shown in Figure A.…”

Section: Resultssupporting

confidence: 49%

Fabrication of Nanostructured Thermoelectric Bismuth Telluride Thick Films by Electrochemical Deposition

et al. 2006

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Bismuth telluride (Bi 2 Te 3 )-based solid solutions are state-of-the-art thermoelectric (TE) materials for cooling applications at room temperature with a high figure of merit ZT. Nanostructured TE bismuth telluride thick films have been fabricated by electrodeposition from a solution containing bismuth nitrate and tellurium dioxide in 1 M nitric acid onto gold-sputtered aluminum substrates. A conventional threeelectrode cell was used with a platinum sheet as the counter electrode and a saturated calomel electrode (SCE) as the reference electrode. Ethylene glycol (EG) was added to the electrolyte in order to increase the thickness of the deposited films, and its effect on the structure, morphology, and compositional stoichiometry of the deposited film was investigated. SEM and XRD were used for structural and compositional characterization. Bismuth telluride films with thicknesses of ca. 350 µm, a stoichiometric composition of Bi 2 Te 3 , and a hexagonal crystal structure were obtained. A microprobe technique was used to measure the lateral Seebeck coefficient in several samples. The free-standing films were shown to be of high homogeneity, where the abundance distribution of the Seebeck coefficient showed a half width of less than 1 µV K -1 and a high electrical conductivity of around 450 S cm -1 at room temperature.

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Section: Resultssupporting

confidence: 49%

Fabrication of Nanostructured Thermoelectric Bismuth Telluride Thick Films by Electrochemical Deposition

et al. 2006

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“…00-008-0021), all of the detected peaks are indexed as those from the rhombohedral Bi 2 Te 3 crystal [space group ( R 3̅ m ) (166)]. However, the intensity ratios of the peaks are not in agreement with those obtained by XRD on a ground sample, indicating an orientational effect in the film growth . For annealed films, the peak becomes much narrower than the as-deposited film, which indicates a substantial increase of the grain size.…”

Section: Resultsmentioning

confidence: 88%

Effects of Annealing and Doping on Nanostructured Bismuth Telluride Thick Films

Soliman

Zhou

et al. 2008

Chem. Mater.

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Bismuth telluride is the state-of-the-art thermoelectric (TE) material for cooling applications with a figure of merit of ∼1 at 300 K. There is a need for the development of TE materials based on the concept of thick films for miniaturized devices due to mechanical and manufacturing constraints for the thermoelement dimensions. We reported earlier a method for the fabrication of high-quality nanostructured bismuth telluride thick films with thickness from 100 to 350 µm based on electrochemical deposition techniques. In this paper, annealing is performed to further improve the TE performance of the nanostructured bismuth telluride thick films and n/p-type solid solutions are successfully fabricated by doping Se and Sb, respectively. The conditions for both annealing and doping for the thick films are investigated, and the effects of annealing and doping on morphology, crystalline phase, grain size, Seebeck coefficient, homogeneity, electrical conductivity, and power factor of the bismuth telluride thick films have been studied.

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“…These conditions are consistent with reports by others who have used acidic solutions for Bi 2 Te 3 electrodeposition. [17][18][19][20][21][22][23][24][25] However, in our case it is not possible to use pH Ӷ 0 for this study because our ultimate goal is to understand the mechanism of electrodeposition of Bi 2 Te 3 nanowires into porous alumina templates. 28 Bismuth cyclic voltammetry.-The CV observed for a solution containing Bi 3ϩ (0.75 ϫ 10 Ϫ2 M) dissolved in HNO 3 is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The electrodeposition of Bi 2 Te 3 is a fast, simple, and low cost synthetic method, [17][18][19][20][21][22][23][24][25] and a good choice for the fabrication of nanowires. However, the processes involved in the electrodeposition of Bi 2 Te 3 are not very well understood.…”

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Insights into the Electrodeposition of Bi[sub 2]Te[sub 3]

Martín‐González¹,

Prieto²,

Gronsky

et al. 2002

J. Electrochem. Soc.

244

193

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In this paper, the processes associated with the electrodeposition of bismuth telluride (Bi 2 Te 3 ), a thermoelectric material, are reported along with an analysis of the composition and crystallinity of the resulting films. The electrodeposition can be described by the general reaction 3HTeO 2 ϩ ϩ 2Bi 3ϩ ϩ 18e Ϫ ϩ 9H ϩ → Bi 2 Te 3 ϩ 6H 2 O. Cyclic voltammetry studies of Bi, Te, and Bi/Te dissolved in 1 M HNO 3 reveal two different underlying processes depending on the deposition potential. One process involves the reduction of HTeO 2 ϩ to Te 0 and a subsequent interaction between reduced Te 0 and Bi 3ϩ to form Bi 2 Te 3 . A second process at more negative reduction potentials involves reduction of HTeO 2 ϩ to H 2 Te followed by the chemical interaction with Bi 3ϩ . Both processes result in the production of crystalline Bi 2 Te 3 films in the potential range Ϫ0.1 Ͻ E Ͻ Ϫ0.52 V vs. Ag/AgCl ͑3 M NaCl͒ on Pt substrates as determined by powder X-ray diffraction ͑XRD͒. Electron probe microanalyses and XRD reveal that the films are bismuth-rich and less oriented for more negative deposition potentials.Solid-state thermoelectric devices convert thermal energy from a temperature gradient into electrical energy ͑the Seebeck effect͒ or electrical energy into a temperature gradient ͑the Peltier effect͒. Thermoelectric power generators are used most notably in spacecraft power generation systems ͑for example, in Voyager I and II͒ 1,2 and in thermocouples for temperature measurement, while thermoelectric coolers are largely used in charge coupled device ͑CCD͒ cameras, laser diodes, microprocessors, blood analyzers, and portable picnic coolers. 1,2 Thermoelectric coolers ͑also known as Peltier coolers͒ offer several advantages over conventional systems. As solid-state devices, they have no moving parts. They use no ozonedepleting chlorofluorocarbons, potentially offering a more environmentally responsible alternative to conventional refrigeration. Although some large-scale applications have been considered ͑on submarines and surface vessels͒, their efficiency is low compared to conventional refrigerators.Scientific and technological interest in the production of nanostructured thermoelectric materials has been driven by recent theoretical studies, which suggest that quantum confinement of electrons and holes could enhance the efficiency of these materials significantly above that of their bulk values. 3-5 This hypothesis has already been verified for thin multilayers of PbTe/Pb 1Ϫx Eu x Te. 6-11 Larger enhancements are predicted for one-dimensional ͑1-D͒ systems ͑nanowires͒ compared to 2-D systems ͑thin films͒. 12,13 These predictions have stimulated research into the preparation of nanowires of thermoelectric materials.Bismuth telluride (Bi 2 Te 3 ) and its doped derivative compounds are considered to be the best materials to date for near roomtemperature thermoelectric applications. 14,15 The maximum figure of merit ͑ZT͒ occurs for optimized doping levels 16 at approximately 70°C with an effective operating range of Ϫ100 to...

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Texture of Electroplated Coatings of Copper and Bismuth Telluride

Cited by 4 publications

References 0 publications

Fabrication of Nanostructured Thermoelectric Bismuth Telluride Thick Films by Electrochemical Deposition

Fabrication of Nanostructured Thermoelectric Bismuth Telluride Thick Films by Electrochemical Deposition

Effects of Annealing and Doping on Nanostructured Bismuth Telluride Thick Films

Insights into the Electrodeposition of Bi[sub 2]Te[sub 3]

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