Jeongha Kim, Sung-Do Kwon, D. Jeong, B. Ju, Seok-Jin Yoon, Jin-Sang Kim
Metal organic vapour phase epitaxy has been investigated for growth of Bi2Te3 and Sb2Te3 films on (001) GaAs substrates using trimethylbismuth, triethylantimony and diisopropyltelluride as metal organic sources. High resolution TEM and X-ray diffraction patterns revealed that films had single crystalline phases with a preferential c-orientation and layered structures resulting from the van der Waals bonding nature in these materials. By optimizing growth parameters such as precursor ratio, growth temperatures, and flow rate in reactor, we could obtain Seebeck coefficient of -160muVK-1 for Bi2Te3 and +110muVK-1 for Sb2Te3 films, respectively. The high Seebeck coefficient and atomistically smooth surface morphologies of these materials are promising for the fabrication of a few nm thick periodic Bi2Te3/Sb 2Te3super lattice structures for thin film thermoelectric device applications
{"title":"Structural Characteristics of Bi2Te3 and Sb2Te3 films on (001) GaAs Substrates grown by MOCVD","authors":"Jeongha Kim, Sung-Do Kwon, D. Jeong, B. Ju, Seok-Jin Yoon, Jin-Sang Kim","doi":"10.1109/ICT.2006.331284","DOIUrl":"https://doi.org/10.1109/ICT.2006.331284","url":null,"abstract":"Metal organic vapour phase epitaxy has been investigated for growth of Bi<sub>2</sub>Te<sub>3</sub> and Sb<sub>2</sub>Te<sub>3</sub> films on (001) GaAs substrates using trimethylbismuth, triethylantimony and diisopropyltelluride as metal organic sources. High resolution TEM and X-ray diffraction patterns revealed that films had single crystalline phases with a preferential c-orientation and layered structures resulting from the van der Waals bonding nature in these materials. By optimizing growth parameters such as precursor ratio, growth temperatures, and flow rate in reactor, we could obtain Seebeck coefficient of -160muVK<sup>-1</sup> for Bi<sub>2</sub>Te<sub>3</sub> and +110muVK<sup>-1</sup> for Sb<sub>2</sub>Te<sub>3</sub> films, respectively. The high Seebeck coefficient and atomistically smooth surface morphologies of these materials are promising for the fabrication of a few nm thick periodic Bi<sub>2</sub>Te<sub>3</sub>/Sb <sub>2</sub>Te<sub>3</sub>super lattice structures for thin film thermoelectric device applications","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122489349","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}
High temperature thermoelectric properties have been measured on a Czochralski pulled Ba8Ga16Ge30 crystal. Complete transport properties obtained in the temperature range from 273K to 1150K. The physical properties are reproducible even after thermal cycling. The Seebeck coefficient reveals the sample to be an n-type conductor with a maximum value of -148 muV/K at 1073K. The electrical resistivity shows the characteristics of a heavily doped semi conductor, and it goes through a maximum at 1073 K with a value of 1.7 mOmega-cm. The thermal conductivity goes through a minimum of 1.25 W/m-K around 900K, and ZT reaches a maximum of 0.9 at 1000 K
{"title":"High temperature thermoelectric properties of Czochralski-pulled Ba8Ga16Ge30","authors":"M. Christensen, G. J. Snyder, B. Iversen","doi":"10.1109/ICT.2006.331265","DOIUrl":"https://doi.org/10.1109/ICT.2006.331265","url":null,"abstract":"High temperature thermoelectric properties have been measured on a Czochralski pulled Ba8Ga16Ge30 crystal. Complete transport properties obtained in the temperature range from 273K to 1150K. The physical properties are reproducible even after thermal cycling. The Seebeck coefficient reveals the sample to be an n-type conductor with a maximum value of -148 muV/K at 1073K. The electrical resistivity shows the characteristics of a heavily doped semi conductor, and it goes through a maximum at 1073 K with a value of 1.7 mOmega-cm. The thermal conductivity goes through a minimum of 1.25 W/m-K around 900K, and ZT reaches a maximum of 0.9 at 1000 K","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131351448","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}
E. Hatzikraniotis, T. Hassapis, T. Kyratsi, K. Paraskevopoulos, M. Kanatzidis
Investigations of ternary and quaternary compounds, Bi and Sb chalcogenides, have shown that several multinary compounds containing alkali metals present promising thermoelectric properties. In this work, the FTIR reflectivity spectra of K2Sb8Se13 crystals are reported and analyzed for the first time. Optical investigations are conducted with or without polarization, in two directions, parallel and perpendicular to the needles. The observed distinct optical anisotropy investigated by means of polarization dependent reflectivity measurements is discussed with respect to the strong structural anisotropy
{"title":"FTIR Reflectivity spectra of Thermoelectric K2Sb8Se13 crystals","authors":"E. Hatzikraniotis, T. Hassapis, T. Kyratsi, K. Paraskevopoulos, M. Kanatzidis","doi":"10.1109/ICT.2006.331379","DOIUrl":"https://doi.org/10.1109/ICT.2006.331379","url":null,"abstract":"Investigations of ternary and quaternary compounds, Bi and Sb chalcogenides, have shown that several multinary compounds containing alkali metals present promising thermoelectric properties. In this work, the FTIR reflectivity spectra of K2Sb8Se13 crystals are reported and analyzed for the first time. Optical investigations are conducted with or without polarization, in two directions, parallel and perpendicular to the needles. The observed distinct optical anisotropy investigated by means of polarization dependent reflectivity measurements is discussed with respect to the strong structural anisotropy","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115030072","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}
Thermoelectric properties of a series of rare earth metal-doped polycrystalline samples of (Ca1-xRx)3Co 2O6 with R = Gd, Tb, Dy and Ho (x = 0 - 0.1) were investigated in the temperature range from 300 K to 1300 K. In a high temperature region above 900 K, a partial rare earth substitution with R 3+ for Ca2+ resulted in appreciable increase in the Seebeck coefficient (S). However, the S value decreased abruptly at low temperatures, and turned to negative values for the Gd- and Tb-doped samples at temperatures below 400 K. With decreasing ionic radii of rare earth elements (Gd3+ > Tb3+ > Dy3+ > Ho3+), the S values increased, while the thermal conductivity (kappa) decreased particularly at temperatures above 700 K. Contrastingly, the influence of rare earth metal substitution on the electrical resistivity (rho) was small; in high temperature region the rho values increased only slightly with decreasing ionic radii of rare earth metals. High-temperature thermoelectric figure-of-merit (Z) of the samples was thereby improved by the late rare-earth metal substitution for Ca2+, particularly for those with Ho3+. A maximum Z value of the Ho-doped sample for x = 0.03 was 1.83 times 10-4 K-1 at 1100 K as compared with 0.37 times 10-4 K-1 for non-doped sample. The electronic structure of the samples was also investigated by x-ray photoemission spectroscopy (XPS) technique. The charge-transfer satellite structure of Co 2p core-level spectra was observed for the Gd-and Tb-doped samples, while the satellite is negligible for the other samples
{"title":"Thermoelectric properties and local electronic structure of rare earth-doped Ca3Co2O6","authors":"N. Nong, M. Ohtaki","doi":"10.1109/ICT.2006.331270","DOIUrl":"https://doi.org/10.1109/ICT.2006.331270","url":null,"abstract":"Thermoelectric properties of a series of rare earth metal-doped polycrystalline samples of (Ca<sub>1-x</sub>R<sub>x</sub>)<sub>3</sub>Co <sub>2</sub>O<sub>6</sub> with R = Gd, Tb, Dy and Ho (x = 0 - 0.1) were investigated in the temperature range from 300 K to 1300 K. In a high temperature region above 900 K, a partial rare earth substitution with R <sup>3+</sup> for Ca<sup>2+</sup> resulted in appreciable increase in the Seebeck coefficient (S). However, the S value decreased abruptly at low temperatures, and turned to negative values for the Gd- and Tb-doped samples at temperatures below 400 K. With decreasing ionic radii of rare earth elements (Gd<sup>3+</sup> > Tb<sup>3+</sup> > Dy<sup>3+</sup> > Ho<sup>3+</sup>), the S values increased, while the thermal conductivity (kappa) decreased particularly at temperatures above 700 K. Contrastingly, the influence of rare earth metal substitution on the electrical resistivity (rho) was small; in high temperature region the rho values increased only slightly with decreasing ionic radii of rare earth metals. High-temperature thermoelectric figure-of-merit (Z) of the samples was thereby improved by the late rare-earth metal substitution for Ca<sup>2+</sup>, particularly for those with Ho<sup>3+</sup>. A maximum Z value of the Ho-doped sample for x = 0.03 was 1.83 times 10<sup>-4</sup> K<sup>-1 </sup> at 1100 K as compared with 0.37 times 10<sup>-4</sup> K<sup>-1 </sup> for non-doped sample. The electronic structure of the samples was also investigated by x-ray photoemission spectroscopy (XPS) technique. The charge-transfer satellite structure of Co 2p core-level spectra was observed for the Gd-and Tb-doped samples, while the satellite is negligible for the other samples","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125400366","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}
T. Nemoto, M. Akasaka, T. Iida, J. Sato, K. Nishio, T. Takei, Y. Takanashi
Mg2Si and Mg2Si incorporating oxides such as Al2O3, ZrO2, SnO2, ZnO, B 2O3 and CuO were formed by using a spark-plasma sintering (SPS) technique. The "oxide-incorporated" Mg2Si samples exhibited the formation of voids and also clusters of oxide materials. The effects of oxide incorporation into Mg2Si were investigated in an attempt to identify oxides that exhibit lower thermal conductivity but an equal power factor and figure-of-merit when compared with pure Mg2Si. In the cases of the samples of Mg2Si that incorporated SnO2, ZnO, ZrO2 and Al2O3, the observed power factors showed no significant temperature dependence, with values comparable to those observed for pure Mg2Si at about 2 times 10-5 W/cmK2. The incorporation of SnO2 or ZnO improved the lattice thermal conductivity over the whole measured temperature range when compared with a pure Mg2Si sample. The observed deviations in the values of the figures-of-merit between the SnO2 or ZnO-incorporated Mg2Si and the pure Mg2Si (without the oxide) were observed as being rather small, with no remarkable dissidence in the measured values. It was realized that the SnO2- and the ZnO-incorporated Mg2Si samples exhibited thermal conductivity values that were more than 20 % lower than that of pure Mg2Si at around 773 K
{"title":"Characterization of oxide-incorporated n-type Mg2Si prepared by a spark plasma sintering method","authors":"T. Nemoto, M. Akasaka, T. Iida, J. Sato, K. Nishio, T. Takei, Y. Takanashi","doi":"10.1109/ICT.2006.331355","DOIUrl":"https://doi.org/10.1109/ICT.2006.331355","url":null,"abstract":"Mg<sub>2</sub>Si and Mg<sub>2</sub>Si incorporating oxides such as Al<sub>2</sub>O<sub>3</sub>, ZrO<sub>2</sub>, SnO<sub>2</sub>, ZnO, B <sub>2</sub>O<sub>3</sub> and CuO were formed by using a spark-plasma sintering (SPS) technique. The \"oxide-incorporated\" Mg<sub>2</sub>Si samples exhibited the formation of voids and also clusters of oxide materials. The effects of oxide incorporation into Mg<sub>2</sub>Si were investigated in an attempt to identify oxides that exhibit lower thermal conductivity but an equal power factor and figure-of-merit when compared with pure Mg<sub>2</sub>Si. In the cases of the samples of Mg<sub>2</sub>Si that incorporated SnO<sub>2</sub>, ZnO, ZrO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub>, the observed power factors showed no significant temperature dependence, with values comparable to those observed for pure Mg<sub>2</sub>Si at about 2 times 10<sup>-5</sup> W/cmK<sup>2</sup>. The incorporation of SnO<sub>2</sub> or ZnO improved the lattice thermal conductivity over the whole measured temperature range when compared with a pure Mg<sub>2</sub>Si sample. The observed deviations in the values of the figures-of-merit between the SnO<sub>2 </sub>or ZnO-incorporated Mg<sub>2</sub>Si and the pure Mg<sub>2</sub>Si (without the oxide) were observed as being rather small, with no remarkable dissidence in the measured values. It was realized that the SnO<sub>2</sub>- and the ZnO-incorporated Mg<sub>2</sub>Si samples exhibited thermal conductivity values that were more than 20 % lower than that of pure Mg<sub>2</sub>Si at around 773 K","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127552898","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}
T. Kyratsi, E. Hatzikraniotis, A. Tsiappos, K. Paraskevopoulos, M. Kanatzidis
beta-K2Bi8Se13 and its solid solutions have been found to be interesting for thermoelectric investigations mainly due to their low thermal conductivity and highly anisotropic electrical properties. Solid solution series of the type K 2Bi8-xSbxSe13, K2-x RbxBi8Se13 as well as K2 Bi8Se13-xSx has been studied. Interestingly, K2Bi8-xSbxSe13 presents both n- and p-type of character depending on the Sb concentration in the lattice. In this work, the n-to-p transition with Sb concentration is presented. The Seebeck coefficient is discussed as a function of x and the transition at room temperature appears at the stoichiometric region of x ~ 6. The transition temperature for the members of the series increases with Sb incorporation in the lattice and this can be attributed to the band gap increase
{"title":"n-to-p Transition on K2Bi8-xSbxSe13 Series","authors":"T. Kyratsi, E. Hatzikraniotis, A. Tsiappos, K. Paraskevopoulos, M. Kanatzidis","doi":"10.1109/ICT.2006.331383","DOIUrl":"https://doi.org/10.1109/ICT.2006.331383","url":null,"abstract":"beta-K<sub>2</sub>Bi<sub>8</sub>Se<sub>13</sub> and its solid solutions have been found to be interesting for thermoelectric investigations mainly due to their low thermal conductivity and highly anisotropic electrical properties. Solid solution series of the type K <sub>2</sub>Bi<sub>8-x</sub>Sb<sub>x</sub>Se<sub>13</sub>, K<sub>2-x </sub>Rb<sub>x</sub>Bi<sub>8</sub>Se<sub>13</sub> as well as K<sub>2 </sub>Bi<sub>8</sub>Se<sub>13-x</sub>S<sub>x</sub> has been studied. Interestingly, K<sub>2</sub>Bi<sub>8-x</sub>Sb<sub>x</sub>Se<sub>13</sub> presents both n- and p-type of character depending on the Sb concentration in the lattice. In this work, the n-to-p transition with Sb concentration is presented. The Seebeck coefficient is discussed as a function of x and the transition at room temperature appears at the stoichiometric region of x ~ 6. The transition temperature for the members of the series increases with Sb incorporation in the lattice and this can be attributed to the band gap increase","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133850853","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}
CoSb3 bulk materials were successfully prepared by Sb self-flux technique, and the synthesis conditions were widely investigated to obtain the high purity compounds utilizing a quantitative powder XRD study with the Rietveld analysis applying a multi-phase-fitting condition. The reaction temperature range for the Sb self-flux technique was extended up to 1123 K to promote the reaction in the Co-Sb system. The relation between the reaction temperature and the chemical composition is discussed to optimize the preparation conditions in the Sb self-flux technique
{"title":"Optimization of synthesis conditions for CoSb3 compounds prepared by Sb self-flux method","authors":"T. Souma, M. Ohtaki","doi":"10.1109/ICT.2006.331385","DOIUrl":"https://doi.org/10.1109/ICT.2006.331385","url":null,"abstract":"CoSb3 bulk materials were successfully prepared by Sb self-flux technique, and the synthesis conditions were widely investigated to obtain the high purity compounds utilizing a quantitative powder XRD study with the Rietveld analysis applying a multi-phase-fitting condition. The reaction temperature range for the Sb self-flux technique was extended up to 1123 K to promote the reaction in the Co-Sb system. The relation between the reaction temperature and the chemical composition is discussed to optimize the preparation conditions in the Sb self-flux technique","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126984900","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. Kuriyama, M. Nohara, T. Sasagawa, K. Takubo, T. Mizokawa, K. Kimura, H. Takagi
We report high temperature thermoelectric properties of doped Delafossite oxide CuRh1-xMgxO2. The parent compound CuRhO2 is a band insulator and becomes metallic upon Mg doping for Rh. We found that polycrystalline CuRh1-xMgxO2 shows a large thermoelectric power S ~ +270 muV/K despite its low resistivity ~6 mOmegacm at high temperatures around 1000 K. Combining these with a thermal conductivity kappa ~ 80 mW/cm K, we estimate a large dimensionless figure of merit ZT 7sim; 0.15 at 1000 K
{"title":"High-temperature thermoelectric properties of Delafossite oxide CuRh1-xMgxO2","authors":"H. Kuriyama, M. Nohara, T. Sasagawa, K. Takubo, T. Mizokawa, K. Kimura, H. Takagi","doi":"10.1109/ICT.2006.331289","DOIUrl":"https://doi.org/10.1109/ICT.2006.331289","url":null,"abstract":"We report high temperature thermoelectric properties of doped Delafossite oxide CuRh<sub>1-x</sub>Mg<sub>x</sub>O<sub>2</sub>. The parent compound CuRhO<sub>2</sub> is a band insulator and becomes metallic upon Mg doping for Rh. We found that polycrystalline CuRh<sub>1-x</sub>Mg<sub>x</sub>O<sub>2</sub> shows a large thermoelectric power S ~ +270 muV/K despite its low resistivity ~6 mOmegacm at high temperatures around 1000 K. Combining these with a thermal conductivity kappa ~ 80 mW/cm K, we estimate a large dimensionless figure of merit ZT 7sim; 0.15 at 1000 K","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123431509","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 solid solutions of beta-K2Bi8Se13 are an interesting series of materials for thermoelectric investigations because they possess very low thermal conductivity and relatively high power factor. Moreover, the sulfur-substituted K2 Bi8Se13-xSx compounds were found to have promising properties showing the potential for high temperature applications. Due to their high anisotropic properties, we aim to develop polycrystalline pellets and study their thermoelectric properties as well as their potential to achieve promising power factor. In this work, for the first time pressed pellet samples of the K2 Bi8Se13 system are presented. The morphology of the material and the thermoelectric properties of pressed pellets of the K2Bi8Se13-xSx compounds were studied in terms of sintering conditions
{"title":"Thermoelectric Properties of Pressed Pellets and Pressureless Sintering in the K2Bi8Se13-xSx System","authors":"A. Tsiappos, T. Kyratsi, M. Kanatzidis","doi":"10.1109/ICT.2006.331346","DOIUrl":"https://doi.org/10.1109/ICT.2006.331346","url":null,"abstract":"The solid solutions of beta-K<sub>2</sub>Bi<sub>8</sub>Se<sub>13 </sub> are an interesting series of materials for thermoelectric investigations because they possess very low thermal conductivity and relatively high power factor. Moreover, the sulfur-substituted K<sub>2 </sub>Bi<sub>8</sub>Se<sub>13-x</sub>S<sub>x</sub> compounds were found to have promising properties showing the potential for high temperature applications. Due to their high anisotropic properties, we aim to develop polycrystalline pellets and study their thermoelectric properties as well as their potential to achieve promising power factor. In this work, for the first time pressed pellet samples of the K<sub>2 </sub>Bi<sub>8</sub>Se<sub>13</sub> system are presented. The morphology of the material and the thermoelectric properties of pressed pellets of the K<sub>2</sub>Bi<sub>8</sub>Se<sub>13-x</sub>S<sub>x</sub> compounds were studied in terms of sintering conditions","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125806515","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}
A series of seven bulk crystals of Zn4+xSb3 (-0.12 ⩽ x ⩽ 0.12) are successfully prepared, and the relation between the Zn content and the thermoelectric properties is investigated. The sample with the nominal composition of Zn3.96 Sb3 (x = -0.04) contain the maximum mass fraction of Zn 4Sb3. The shapes of the S(T) and ρ(T) curves are drastically changed with varying x in the temperature range from 300 K to 700 K. Whereas the lower x leads to lower ρ, the magnitude of S unchanges, resulting in the fact that the power factor of the Zn-poor compositions in the Zn4+xSb3 system is lower than that of the Zn-rich compositions. The details of the influence of the Zn content and the scope of the improvement of the durability are discussed.
{"title":"Relation between zn content and thermoelectric properties of zn4+xsb3 (-0.12⩽x⩽0.12)","authors":"T. Souma, M. Ohtaki","doi":"10.1109/ICT.2006.331384","DOIUrl":"https://doi.org/10.1109/ICT.2006.331384","url":null,"abstract":"A series of seven bulk crystals of Zn<sub>4+x</sub>Sb<sub>3</sub> (-0.12 ⩽ x ⩽ 0.12) are successfully prepared, and the relation between the Zn content and the thermoelectric properties is investigated. The sample with the nominal composition of Zn<sub>3.96 </sub>Sb<sub>3</sub> (x = -0.04) contain the maximum mass fraction of Zn <sub>4</sub>Sb<sub>3</sub>. The shapes of the S(T) and ρ(T) curves are drastically changed with varying x in the temperature range from 300 K to 700 K. Whereas the lower x leads to lower ρ, the magnitude of S unchanges, resulting in the fact that the power factor of the Zn-poor compositions in the Zn<sub>4+x</sub>Sb<sub>3</sub> system is lower than that of the Zn-rich compositions. The details of the influence of the Zn content and the scope of the improvement of the durability are discussed.","PeriodicalId":346555,"journal":{"name":"2006 25th International Conference on Thermoelectrics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128290743","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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