Progress in developing high cooling power, short-legged thermoelectric coolers (TECs) for local cooling of high power density electro-optic components is represented. Different competitive methods aimed toward TEC miniaturization, such as processing of bulk materials as well as thin-film and thick-film technique, are analyzed and their advantages and disadvantages are discussed. Bulk material based technology is developed which allow production of TECs with TE leg height below 0.2 mm. The TECs show temperature differences comparable to those for standard bulk coolers
{"title":"Miniature Thermoelectric Modules with Increased Cooling Power","authors":"V. Semenyuk","doi":"10.1109/ICT.2006.331216","DOIUrl":"https://doi.org/10.1109/ICT.2006.331216","url":null,"abstract":"Progress in developing high cooling power, short-legged thermoelectric coolers (TECs) for local cooling of high power density electro-optic components is represented. Different competitive methods aimed toward TEC miniaturization, such as processing of bulk materials as well as thin-film and thick-film technique, are analyzed and their advantages and disadvantages are discussed. Bulk material based technology is developed which allow production of TECs with TE leg height below 0.2 mm. The TECs show temperature differences comparable to those for standard bulk coolers","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122374899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Zide, G. Zeng, J. Bahk, W. Kim, S. Singer, D. Vashaee, Z. Bian, R. Singh, J. Bowers, A. Majumdar, A. Shakouri, A. Gossard
We present the molecular beam epitaxial growth of nanocomposites consisting of semimetallic ErAs nanoparticles which are epitaxially embedded within InGaAlAs-based semiconductors. The properties of nanocomposites can be drastically different from that of the constituents, and in this case, the incorporation of ErAs is used to increase the thermoelectric power factor and decrease the lattice thermal conductivity, resulting in an increase in the figure of merit, ZT. In addition, the thermoelectric power factor is increased due to electron filtering (solid-state thermionic emission) by barriers within the composite. In one geometry, barriers of InGaAlAs, a wider bandgap semiconductor, are introduced into an ErAs:InGaAs nanocomposite. In a second geometry, ErAs particles are embedded directly into InGaAlAs. Electron filtering occurs due to the Schottky barriers which are formed surrounding the particles. We present a 400-element array based on these materials for thermoelectric power generation; a power density >1 W/cm2 is demonstrated with a temperature gradient of 120degC
{"title":"Nanocomposites of Semimetallic ErAs Nanoparticles Epitaxially Embedded within InGaAlAs-based Semiconductors for Thermoelectric Materials","authors":"J. Zide, G. Zeng, J. Bahk, W. Kim, S. Singer, D. Vashaee, Z. Bian, R. Singh, J. Bowers, A. Majumdar, A. Shakouri, A. Gossard","doi":"10.1109/ICT.2006.331369","DOIUrl":"https://doi.org/10.1109/ICT.2006.331369","url":null,"abstract":"We present the molecular beam epitaxial growth of nanocomposites consisting of semimetallic ErAs nanoparticles which are epitaxially embedded within InGaAlAs-based semiconductors. The properties of nanocomposites can be drastically different from that of the constituents, and in this case, the incorporation of ErAs is used to increase the thermoelectric power factor and decrease the lattice thermal conductivity, resulting in an increase in the figure of merit, ZT. In addition, the thermoelectric power factor is increased due to electron filtering (solid-state thermionic emission) by barriers within the composite. In one geometry, barriers of InGaAlAs, a wider bandgap semiconductor, are introduced into an ErAs:InGaAs nanocomposite. In a second geometry, ErAs particles are embedded directly into InGaAlAs. Electron filtering occurs due to the Schottky barriers which are formed surrounding the particles. We present a 400-element array based on these materials for thermoelectric power generation; a power density >1 W/cm2 is demonstrated with a temperature gradient of 120degC","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122400564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have prepared polycrystalline specimens of [Ca2CoO 3.1]0.62CoO2 (0 les x les 0.03) using the conventional solid-state reaction method, and investigated the Pb substitution effect on the TE properties. With the Pb substitution, both the electrical resistivity and Seebeck coefficient do not change drastically. This is attributed to the carrier concentration. Seebeck and Hall coefficient measurements reveal that the major charge carriers in the samples are holes, however, the carrier concentration does not change drastically with increasing x. The magnetic susceptibility measurements also show that Pb ions take divalent state in the rock salt type [Ca2CoO3] block layer. The valence state of Co ions in the CdI2 type [CoO2] sheet was 3.1+ and that of Co ions in the block layer was 3.6+. The dimensionless figure of merit for the x = 0 sample at room temperature was 0.02, which is approximately equal to the corresponding values of a polycrystalline sample of NaCo2O4
采用常规固相反应法制备了[Ca2CoO 3.1]0.62CoO2 (0 les x les 0.03)的多晶样品，并研究了Pb取代对TE性能的影响。铅取代后，电阻率和塞贝克系数变化不大。这归因于载流子浓度。Seebeck和Hall系数测量表明，样品中的载流子主要为空穴，但载流子浓度随x的增加变化不大。磁化率测量也表明，Pb离子在岩盐型[Ca2CoO3]块层中呈二价态。CdI2型[CoO2]薄片中Co离子的价态为3.1+，阻滞层中Co离子的价态为3.6+。x = 0样品在室温下的无因次优值为0.02，近似等于NaCo2O4多晶样品的相应值
{"title":"Thermoelectric properties of Pb doped [Ca2CoO3.1]0.62CoO2","authors":"H. Nakatsugawa, H. Jeong, R. Kim, N. Gomi","doi":"10.1109/ICT.2006.331235","DOIUrl":"https://doi.org/10.1109/ICT.2006.331235","url":null,"abstract":"We have prepared polycrystalline specimens of [Ca<sub>2</sub>CoO <sub>3.1</sub>]<sub>0.62</sub>CoO<sub>2</sub> (0 les x les 0.03) using the conventional solid-state reaction method, and investigated the Pb substitution effect on the TE properties. With the Pb substitution, both the electrical resistivity and Seebeck coefficient do not change drastically. This is attributed to the carrier concentration. Seebeck and Hall coefficient measurements reveal that the major charge carriers in the samples are holes, however, the carrier concentration does not change drastically with increasing x. The magnetic susceptibility measurements also show that Pb ions take divalent state in the rock salt type [Ca<sub>2</sub>CoO<sub>3</sub>] block layer. The valence state of Co ions in the CdI<sub>2</sub> type [CoO<sub>2</sub>] sheet was 3.1+ and that of Co ions in the block layer was 3.6+. The dimensionless figure of merit for the x = 0 sample at room temperature was 0.02, which is approximately equal to the corresponding values of a polycrystalline sample of NaCo<sub>2</sub>O<sub>4</sub>","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121229993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Iwasaki, H. Morita, D. Chikamori, M. Koyano, Y. Hasegawa
Figures of merit, ZT have been measured by the improved Harman method on Bi-microwire arrays, where the diameter of the microwire is changed from 6 mum to 50 mum. The ZT values are widely distributed among the several arrays, on the contrary to those for the bulk samples. Clear correlation between the microwire diameters and ZT cannot be seen among the measured arrays. Quite large ZT of 0.287 was obtained in the 50 mumPhi Bi-microwire array and was 2.6 times larger than that in the polycrystalline bulk material. Absolute value of the Seebeck coefficient, alpha increases with increasing ZT and the thermal conductivity, kappa decreases with ZT. The relationship of the Seebeck coefficient and the thermal conductivity with ZT shows similar behavior to those in bismuth single crystals reported previously. It is concluded that the large improvement of ZT is due to the homogeneous crystal orientation in Bi-microwires constituting the array. The obtained results are important in the development of the thermoelectric devices with much higher energy conversion efficiency. It is also emphasized that the Harman method, in which the Peltier heat is utilized, is very appropriate in the study of the microscopic thermoelectric system
{"title":"Enhancement of the Figure of Merit in Bi-microwire Arrays","authors":"H. Iwasaki, H. Morita, D. Chikamori, M. Koyano, Y. Hasegawa","doi":"10.1109/ICT.2006.331336","DOIUrl":"https://doi.org/10.1109/ICT.2006.331336","url":null,"abstract":"Figures of merit, ZT have been measured by the improved Harman method on Bi-microwire arrays, where the diameter of the microwire is changed from 6 mum to 50 mum. The ZT values are widely distributed among the several arrays, on the contrary to those for the bulk samples. Clear correlation between the microwire diameters and ZT cannot be seen among the measured arrays. Quite large ZT of 0.287 was obtained in the 50 mumPhi Bi-microwire array and was 2.6 times larger than that in the polycrystalline bulk material. Absolute value of the Seebeck coefficient, alpha increases with increasing ZT and the thermal conductivity, kappa decreases with ZT. The relationship of the Seebeck coefficient and the thermal conductivity with ZT shows similar behavior to those in bismuth single crystals reported previously. It is concluded that the large improvement of ZT is due to the homogeneous crystal orientation in Bi-microwires constituting the array. The obtained results are important in the development of the thermoelectric devices with much higher energy conversion efficiency. It is also emphasized that the Harman method, in which the Peltier heat is utilized, is very appropriate in the study of the microscopic thermoelectric system","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121297254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Okamoto, K. Fukui, K. Fujii, T. Suenaga, J. Morimoto
We have examined the feasibility for photo sensor application of Si-Ge-Au amorphous thin films. It is clarified the optimum sample preparation condition for photo sensor application. Photo sensing properties of optimum prepared samples were measured. As a result, specific sensitivity reached up to 0.019 V/W as row material. This value means that Si-Ge-Au amorphous thin film is powerful candidate for primary material of photo-thermoelectric type photo sensor
{"title":"The study for photo-thermoelectric effect of Si-Ge-Au amorphous thin films as non-cooled type photo sensor","authors":"Y. Okamoto, K. Fukui, K. Fujii, T. Suenaga, J. Morimoto","doi":"10.1109/ICT.2006.331306","DOIUrl":"https://doi.org/10.1109/ICT.2006.331306","url":null,"abstract":"We have examined the feasibility for photo sensor application of Si-Ge-Au amorphous thin films. It is clarified the optimum sample preparation condition for photo sensor application. Photo sensing properties of optimum prepared samples were measured. As a result, specific sensitivity reached up to 0.019 V/W as row material. This value means that Si-Ge-Au amorphous thin film is powerful candidate for primary material of photo-thermoelectric type photo sensor","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116421561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Yubuta, S. Okada, Y. Miyazaki, I. Terasaki, T. Kajitani
The crystal structures of thermoelectric (TE) compounds Bi1.91Sr2.0Rh1.77Ox and Bi 2.12Ba2.00Rh1.95Ox are investigated by means of electron diffraction measurements and high-resolution electron microscopy. These compounds have layered structures and consist of two interpenetrating subsystems exhibiting incommensurated periodicities along b-axis. Both subsystems, CdI2 -type RhO2 sheets and a distorted four-layered rock-salt (RS)-type (Bi,(Sr,Ba))O blocks, have common a-, c-axes and beta;-angles. On the other hand, the ratios of two axis lengths, i.e., b 1 (RhO2 sheet) / b2 (RS-type block), are irrational. Based on the cation ratio and b1/b2 value, the structural formulae are expressed as [(Bi1-x>Rhx)2(Sr1-yBi y)2O4+delta]0.63RhO2 with x = 0.077, y = 0.016 and delta = 0.46 for the Sr-system and [(Bi1-x>Rhx)2(Sr1-yBi y)2O4+delta]0.56RhO2 with x = 0.037, y = 0.047 and delta = 0.39 for the Ba-system, respectively. Based on the electron diffraction measurements, it is found that these compounds have irrational modulation vectors, q1 = -a* + 0.63b1* and q2 = 0.17b1* + c for Bi-Sr-Rh-O, and q1 = -a* + 0.56b1* and q 2 = 0.11b1* + 0.35c* for Bi-Ba-Rh-O, respectively, being the indications of (3+2) dimensional structures. High-resolution images taken with the incident electron beam parallel to the a- and c-axes clearly exhibit modulated atomic arrangements. These compounds are characterized by the displacement modulations in both RhO2 layers and the RS-type blocks
{"title":"High-resolution electron microscopy of thermoelectric compounds Bi-(Sr,Ba)-Rh-O","authors":"K. Yubuta, S. Okada, Y. Miyazaki, I. Terasaki, T. Kajitani","doi":"10.1109/ICT.2006.331286","DOIUrl":"https://doi.org/10.1109/ICT.2006.331286","url":null,"abstract":"The crystal structures of thermoelectric (TE) compounds Bi<sub>1.91</sub>Sr<sub>2.0</sub>Rh<sub>1.77</sub>O<sub>x</sub> and Bi <sub>2.12</sub>Ba<sub>2.00</sub>Rh<sub>1.95</sub>O<sub>x</sub> are investigated by means of electron diffraction measurements and high-resolution electron microscopy. These compounds have layered structures and consist of two interpenetrating subsystems exhibiting incommensurated periodicities along b-axis. Both subsystems, CdI<sub>2 </sub>-type RhO<sub>2</sub> sheets and a distorted four-layered rock-salt (RS)-type (Bi,(Sr,Ba))O blocks, have common a-, c-axes and beta;-angles. On the other hand, the ratios of two axis lengths, i.e., b <sub>1</sub> (RhO<sub>2</sub> sheet) / b<sub>2</sub> (RS-type block), are irrational. Based on the cation ratio and b<sub>1</sub>/b<sub>2</sub> value, the structural formulae are expressed as [(Bi<sub>1-x></sub>Rh<sub>x</sub>)<sub>2</sub>(Sr<sub>1-y</sub>Bi <sub>y</sub>)<sub>2</sub>O<sub>4+delta</sub>]<sub>0.63</sub>RhO<sub>2 </sub> with x = 0.077, y = 0.016 and delta = 0.46 for the Sr-system and [(Bi<sub>1-x></sub>Rh<sub>x</sub>)<sub>2</sub>(Sr<sub>1-y</sub>Bi <sub>y</sub>)<sub>2</sub>O<sub>4+delta</sub>]<sub>0.56</sub>RhO<sub>2 </sub> with x = 0.037, y = 0.047 and delta = 0.39 for the Ba-system, respectively. Based on the electron diffraction measurements, it is found that these compounds have irrational modulation vectors, q<sub>1 </sub> = -a* + 0.63b<sub>1</sub>* and q<sub>2</sub> = 0.17b<sub>1</sub>* + c for Bi-Sr-Rh-O, and q<sub>1</sub> = -a* + 0.56b<sub>1</sub>* and q <sub>2</sub> = 0.11b<sub>1</sub>* + 0.35c* for Bi-Ba-Rh-O, respectively, being the indications of (3+2) dimensional structures. High-resolution images taken with the incident electron beam parallel to the a- and c-axes clearly exhibit modulated atomic arrangements. These compounds are characterized by the displacement modulations in both RhO<sub>2</sub> layers and the RS-type blocks","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116744339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electronic structure and thermoelectric properties of Nax CoO2 ware calculated by using a full-potential linearized augmented plane-wave (FLAPW) method with a generalized gradient approximation (GGA). The partial occupancy of Na ion was taken account by the virtual-crystal like approximation. The calculated density of states is good agreement with the XPS data. The thermoelectric power was calculated by using the results of the band structure calculation within the linearized Boltzmann equation. Energy dependence of a relaxation time was neglected. The calculated thermoelectric power of Na0.85CoO2 reproduced experimental results very well for the wide temperature range without any adjustable parameter
{"title":"Band structure and thermoelectric properties of NaxCoO2","authors":"G.J. Zhao, K. Akai, M. Matsuura","doi":"10.1109/ICT.2006.331388","DOIUrl":"https://doi.org/10.1109/ICT.2006.331388","url":null,"abstract":"The electronic structure and thermoelectric properties of Nax CoO2 ware calculated by using a full-potential linearized augmented plane-wave (FLAPW) method with a generalized gradient approximation (GGA). The partial occupancy of Na ion was taken account by the virtual-crystal like approximation. The calculated density of states is good agreement with the XPS data. The thermoelectric power was calculated by using the results of the band structure calculation within the linearized Boltzmann equation. Energy dependence of a relaxation time was neglected. The calculated thermoelectric power of Na0.85CoO2 reproduced experimental results very well for the wide temperature range without any adjustable parameter","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127152817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Bérardan, E. Alleno, C. Godart, H. Benyakoub, H. Flandorfer, O. Rouleau, E. Leroy
We report on the preparation of nanocrystalline filled skutterudites in the series CeyFe4-xCoxSb12 by mechanical alloying. X-ray diffraction and energy dispersive X-ray spectroscopy reveal that skutterudites can be prepared with an homogeneity range larger than what can be obtained by powder metallurgy (PM). Interestingly, no after-milling thermal treatment is required to prepare essentially single phase samples (~90-95%). This is an important difference with skutterudites prepared by PM which only form after long term annealing below the peritectic decomposition temperature. Differential thermal analysis shows that grain growth occurs above ~350degC and that the peritectic decomposition temperature is similar to PM- (i.e. 750degC for x = 1). Grain sizes are in the 12-30 nm range as deduced from Rietveld refinements of X-ray diffraction data and scanning electron microscopy. Cerium is trivalent in nanocrystalline filled skutterudites, as it is in samples prepared by PM. Both p-type and n-type skutterudites can be obtained but values of the Seebeck coefficient are of the same order of magnitude as in PM samples only for p-type skutterudites
{"title":"Synthesis of nanocrystalline filled skutterudites by mechanical alloying","authors":"D. Bérardan, E. Alleno, C. Godart, H. Benyakoub, H. Flandorfer, O. Rouleau, E. Leroy","doi":"10.1109/ICT.2006.331321","DOIUrl":"https://doi.org/10.1109/ICT.2006.331321","url":null,"abstract":"We report on the preparation of nanocrystalline filled skutterudites in the series CeyFe4-xCoxSb12 by mechanical alloying. X-ray diffraction and energy dispersive X-ray spectroscopy reveal that skutterudites can be prepared with an homogeneity range larger than what can be obtained by powder metallurgy (PM). Interestingly, no after-milling thermal treatment is required to prepare essentially single phase samples (~90-95%). This is an important difference with skutterudites prepared by PM which only form after long term annealing below the peritectic decomposition temperature. Differential thermal analysis shows that grain growth occurs above ~350degC and that the peritectic decomposition temperature is similar to PM- (i.e. 750degC for x = 1). Grain sizes are in the 12-30 nm range as deduced from Rietveld refinements of X-ray diffraction data and scanning electron microscopy. Cerium is trivalent in nanocrystalline filled skutterudites, as it is in samples prepared by PM. Both p-type and n-type skutterudites can be obtained but values of the Seebeck coefficient are of the same order of magnitude as in PM samples only for p-type skutterudites","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121943288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Braccini, C. Fanciulli, C. Bernini, M. Vignolo, M. Putti, G. Grasso, A. Siri
We report the synthesis and the physical characterization of p- and n-type thermoelectric oxides, i.e. respectively NaxCoO 2 with x nominally close to 0.75 and LaNi1-xCoxO3 with x nominally equal to 0.3, materials that can be used to build unicouples and therefore thermoelectric modules. In order to take advantage of the anisotropy of the NaxCoO2 crystal structure and of the resistivity, the powder-in-tube method usually used to fabricate superconducting tapes has been employed for the first time to produce thermoelectric wires and tapes, also based on the similarity between the thermoelectric cobalt oxides and the superconducting cuprates. Connectivity was improved through drawing, while texturing was induced in tapes through flat-rolling. This made it possible to significantly reduce the resistivity value, thus enhancing the power factor and the figure of merit of such oxides. Various cold working procedures have been exploited: this method is a fast, reliable way to produce TE legs on a large scale and it has been applied also to the production of the n-type LaNi1-xCoxO3
{"title":"Fabrication of p- and n-type Thermoelectric Cobalt Oxides through the Powder-In-Tube Method","authors":"V. Braccini, C. Fanciulli, C. Bernini, M. Vignolo, M. Putti, G. Grasso, A. Siri","doi":"10.1109/ICT.2006.331371","DOIUrl":"https://doi.org/10.1109/ICT.2006.331371","url":null,"abstract":"We report the synthesis and the physical characterization of p- and n-type thermoelectric oxides, i.e. respectively NaxCoO 2 with x nominally close to 0.75 and LaNi1-xCoxO3 with x nominally equal to 0.3, materials that can be used to build unicouples and therefore thermoelectric modules. In order to take advantage of the anisotropy of the NaxCoO2 crystal structure and of the resistivity, the powder-in-tube method usually used to fabricate superconducting tapes has been employed for the first time to produce thermoelectric wires and tapes, also based on the similarity between the thermoelectric cobalt oxides and the superconducting cuprates. Connectivity was improved through drawing, while texturing was induced in tapes through flat-rolling. This made it possible to significantly reduce the resistivity value, thus enhancing the power factor and the figure of merit of such oxides. Various cold working procedures have been exploited: this method is a fast, reliable way to produce TE legs on a large scale and it has been applied also to the production of the n-type LaNi1-xCoxO3","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122595200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Dashevsky, E. Rabih, V. Kasiyan, A. Halfin, M. Dariel
Thermal sensors have applications in various areas of science and engineering for detection, measurement, observation and control of radiation. The basic elements of these sensors are the absorbing layer and the thin film battery of thermocouples that measures the temperature difference between this layer and the ambient. At present, such sensors can be manufactured by the micro machining process. The essential feature of these sensors is a very thin silica substrate layer. In designing the sensor, the properties of all the layers must be taken into account for optimization of its structure. The sensors detectivity is controlled by the figure of merit of the thermoelectric layer. PbTe is well known material that has found widespread applications in thermoelectric devices. PbTe based materials display unique properties, which are used for optimization of the figure of merit of n- and p-type thermoelectric layers. A simulation model for estimating the characteristics of the film thermoelectric sensor was presented. It was shown Volt-Watt sensitivity is ap 350 V/W for a sensor based on PbTe thermoelectric battery deposited on thin SiO2 layer (thickness ap 1mum). The construction of this sensor can be realized in MEMS design using a Si substrate
{"title":"Development of thin film thermoelectric sensors for a wide spectral range in the MEMS configuration","authors":"Z. Dashevsky, E. Rabih, V. Kasiyan, A. Halfin, M. Dariel","doi":"10.1109/ICT.2006.331328","DOIUrl":"https://doi.org/10.1109/ICT.2006.331328","url":null,"abstract":"Thermal sensors have applications in various areas of science and engineering for detection, measurement, observation and control of radiation. The basic elements of these sensors are the absorbing layer and the thin film battery of thermocouples that measures the temperature difference between this layer and the ambient. At present, such sensors can be manufactured by the micro machining process. The essential feature of these sensors is a very thin silica substrate layer. In designing the sensor, the properties of all the layers must be taken into account for optimization of its structure. The sensors detectivity is controlled by the figure of merit of the thermoelectric layer. PbTe is well known material that has found widespread applications in thermoelectric devices. PbTe based materials display unique properties, which are used for optimization of the figure of merit of n- and p-type thermoelectric layers. A simulation model for estimating the characteristics of the film thermoelectric sensor was presented. It was shown Volt-Watt sensitivity is ap 350 V/W for a sensor based on PbTe thermoelectric battery deposited on thin SiO2 layer (thickness ap 1mum). The construction of this sensor can be realized in MEMS design using a Si substrate","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"309 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122320306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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