Showing papers on "Seebeck coefficient published in 2005"

Thermoelectrics Handbook : Macro to Nano

Abstract: GENERAL PRINCIPLES AND THEORETICAL CONSIDERATIONS General Principles and Basic Considerations D.M. Rowe Modern Thermodynamic Theory of Thermoelectricity L.I. Anatychuk and O.J. Luste Thermoelectric Phenomena under Large Temperature Gradients L.I. Anatychuk and L.P. Bulat Minority Carriers and Thermoelectric Effects in Bipolar Devices Kevin Pipe Effects of Charge Carriers' Interactions on Seebeck Coefficients David Emin Thermal Conductivity of Semiconductors with Complex Crystal Structure V.K. Zaitsev and M.I. Fedorov A Chemical Approach to the First-Principles Modeling of Novel Thermoelectric Materials Luca Bertini, Fausto Cargnoni, and Carlo Gatti Recent Trends for the Design and Optimization of Thermoelectric Materials: A Theoretical Perspective John S. Tse and Dennis D. Klug Thermoelectric Power Generation: Efficiency and Compatibility G. Jeffrey Snyder A New Upper Limit to the Thermoelectric Figure-of-Merit H.J. Goldsmid Thermoelectric Module Design Theories Gao Min Modeling and Characterization of Power Generation Modules Based on Bulk Materials Timothy P. Hogan and Tom Shih Energy Conversion Using Diode-Like Structures Yan Kucherov and Peter Hagelstein Size Effects on Thermal Transport Chandra Mohan Bhandari Thermoelectric Aspects of Strongly Correlated Electron Systems S. Paschen Theory and Modeling in Nanostructured Thermoelectrics Alexander A. Balandin Thermoelectric Power of Carbon Nanotubes G.D. Mahan Phonon-Drag Thermopower of Low-Dimensional Semiconductor Structures Yu.V. Ivanov MATERIAL PREPARATION AND MEASUREMENTS Solid State Synthesis of Thermoelectric Materials B.A. Cook and J.L. Harringa Review of Methods of Thermoelectric Materials Mass Production Yury M. Belov, Sergei M. Maniakin, and Igor V. Morgunov Structural Studies of Thermoelectric Materials Bo Brummerstedt Iversen Measurements of Resistivity and Thermopower: Principles and Practical Realization A.T. Burkov Electrical and Thermal Transport Measurement Techniques for Evaluation of the Figure-of-Merit of Bulk Thermoelectric Materials Terry M. Tritt Measurement of the Thermal Conductivity of Thin Films F. Voelklein, A. Meier, and M. Blumers Solvothermal Synthesis of Nanostructured Thermoelectric Materials X.B. Zhao, T.J. Zhu, and X.H. Ji Approaches to Thermoelectric Standardization E. Muller, C. Stiewe, D.M. Rowe, and S.G.K. Williams THERMOELECTRIC MATERIALS Thermoelectric Properties of Bismuth Antimony Telluride Solid Solutions H. Scherrer and S. Scherrer Bi-Sb Alloys: Thermopower in Magnetic Field V.M. Grabov and O.N. Uryupin Thermoelectrics on the Base of Solid Solutions of Mg2BIV Compounds (BIV = Si, Ge, Sn) V.K. Zaitsev, M.I. Fedorov, I.S. Eremin, and E.A. Gurieva Thermoelectric Properties of the Group V Semimetals J-P. Issi Thermoelectrics of Transition Metal Silicides M. Fedorov and V. Zaitsev Formation and Crystal Chemistry of Clathrates P. Rogl Structure, Thermal Conductivity and Thermoelectric Properties of Clathrate Compounds George S. Nolas Skutterudite-Based Thermoelectrics Ctirad Uher Oxide Thermoelectrics Kunihito Koumoto, Ichiro Terasaki, Tsuyoshi Kajitani, Michitaka Ohtaki, and Ryoji Funahashi Thermoelectric Properties of Electrically Conducting Organic Materials A.I. Casian Shifting the Maximum Figure-of-Merit of (Bi, Sb)2(Te, Se)3 Thermoelectrics to Lower Temperatures V.A. Kutasov, L.N. Lukyanova, and M.V. Vedernikov Functionally Graded Materials for Thermoelectric Applications V.L. Kuznetsov Recent Developments in Low Dimensional Thermoelectric Materials M.S. Dresselhaus and J.P. Heremans Thermoelectric Properties of Nanocrystalline Transition Metal Silicides J. Schumann and A.T. Burkov Nanostructured Skutterudites Mamoun Muhammed and Muhammet Toprak Thermal Conductivity of Nanostructured Thermoelectric Materials C. Dames and G. Chen THERMOELEMENTS, MODULES AND DEVICES Modeling and Optimization of Segmented Thermoelectric Generators for Terrestrial and Space Applications Mohamed S. El-Genk and Hamed H. Saber Thermocouple with a Passive HTSC Leg V.L. Kuznetsov and M.V. Vedernikov Anisotropic Thermoelements A.A. Snarskii and L.P. Bulat Miniaturized Thermoelectric Converters Harald Boettner, Joachim Nurnus, and Axel Schubert Thermoelectric Microelectromechanical Systems (MEMS) F. Voelklein and A. Meier Nanoscale Thermoelectrics Joachim Nurnus, Harald Boettner, and Armin Lambrecht Superlattice Thin-Film Thermoelectric Material and Device Technologies Rama Venkatasubramanian, Edward Siivola, and Brooks O'Quinn THERMOELECTRIC SYSTEMS AND APPLICATIONS Thermoelectric Power Generation System Recovering Industrial Waste Heat Takenobu Kajikawa The Concept of Thermoelectric Power Generation Topping-Up Co-Generation System Takenobu Kajikawa A Thermoelectric Application to Vehicles Kakuei Matsubara and Mitsuru Matsuura Thermoelectric Microgenerators with Isotope Heat Sources L.I. Anatychuk and A.A. Pustovalov Performance and Mass Estimates of CTM-ARPSs with Four GPHS Bricks Mohamed S. El-Genk and Hamed H. Saber Parametric and Optimization Analyses of Cascaded Thermoelectric-Advanced Radioisotope Power Systems with Four GPHS Bricks Mohamed S. El-Genk and Hamed H. Saber Space Missions and Applications Robert D. Abelson Quantum Well Thermoelectric Devices and Applications S. Ghamaty, J.C. Bass, and N.B. Elsner Thermoelectric Cooling of Electro-Optic Components V.A. Semenyuk Thermoelectric Refrigeration for Mass-Market Applications Montag C. Davis, Benjamin P. Banney, Peter T. Clarke, Brett R. Manners, and Robert M. Weymouth APPENDIX I: HISTORY OF THE INTERNATIONAL THERMOELECTRIC SOCIETY C.B. Vining, D.M. Rowe, J. Stockholm, and K.R. Rao APPENDIX II: SELECTED THERMOELECTRIC SOURCES

High-temperature carrier transport and thermoelectric properties of heavily La- or Nb-doped SrTiO3 single crystals

Abstract: Electron and thermal transport properties, i.e., electrical conductivity, carrier concentration, Hall mobility, Seebeck coefficient, thermal conductivity, of heavily La- or Nb-doped SrTiO3 (STO) bulk single crystals were measured at high temperatures, (300–1050K) to clarify the influence of doping upon the thermoelectric performance of STO. The temperature dependence of Hall mobility and Seebeck coefficient changed at ∼750K in all samples because the dominant mechanism for carrier scattering changed with increasing temperature from coupled scattering by polar optical phonons and acoustic phonons to mere acoustic phonon scattering. The density-of-states effective mass of Nb-doped STO, which was estimated from the carrier concentration and Seebeck coefficient, was larger than that of La-doped STO. Thermal conductivity of the samples, which was similar to that of undoped STO single crystal, decreased proportionally to T−1, indicating that the phonon conduction takes place predominantly and the electronic con...

Effect of Ti substitution on the thermoelectric properties of (Zr,Hf)NiSn half-Heusler compounds

Abstract: The effect of Ti substitution on the thermoelectric properties of (Zr,Hf)NiSn half-Heusler compounds was studied. It was found that the substitution of Ti for (Zr,Hf) reduced the thermal conductivity significantly to a low value of 3.0W∕mK at room temperature. In addition, a remarkable enhancement of the Seebeck coefficient due to Ti substitution was observed. Furthermore, doping of the Sn sites in (Ti,Zr,Hf)NiSn with Sb led to a reduction in the electrical resistivity and to a corresponding enhancement of the power factor. In Sb-doped (Ti,Zr,Hf)NiSn compounds, the dimensionless figure of merit, ZT, increased with the increase in temperature and reached a high maximum value of 1.5 at 700K.

Zintl Phases as Thermoelectric Materials: Tuned Transport Properties of the Compounds CaxYb1–xZn2Sb2†

Abstract: Zintl phases are ideal candidates for efficient thermoelectric materials, because they are typically small-bandgap semiconductors with complex structures. Furthermore, such phases allow fine adjustment of dopant concentration without disrupting electronic mobility, which is essential for optimizing thermoelectric material efficiency. The tunability of Zintl phases is demonstrated with the series Ca_xYb_(1-x)Zn_2Sb_2 (0 <= x <= 1). Measurements of the electrical conductivity, Hall mobility, Seebeck coefficient, and thermal conductivity (in the 300-800 K temperature range) show the compounds to behave as heavily doped semiconductors, with transport properties that can be systematically regulated by varying x. Within this series, x = 0 is the most metallic (lowest electrical resistivity, lowest Seebeck coefficient, and highest carrier concentration), and x = 1 is the most semiconducting (highest electrical resistivity, highest Seebeck coefficient, and lowest carrier concentration), while the mobility is largely independent of x. In addition, the structural disorder generated by the incorporation of multiple cations lowers the overall thermal conductivity significantly at intermediate compositions, increasing the thermoelectric figure of merit, zT Thus, both zT and the thermoelectric compatibility factor (like zT, a composite function of the transport properties) can be finely tuned to allow optimization of efficiency in a thermoelectric device.

Reversible thermoelectric nanomaterials

Abstract: A nanostructured thermoelectric material is described. There is a spatial variation in temperature between a first end (108) and a second end (109, 110) of the material. The material has a substantially delta-like density of states (DOS) and a spatial variation in an energy gap between a central energy of the DOS and a quasi-Fermi energy of the material is proportional to the spatial variation in temperature such that the Seebeck coefficient of the material is substantially spatially invariant. The spatial variation in the energy gap may be determined by inhomogeneous doping (7) or by a spatial variation in the energy of the miniband (102, 104) of the material.

Nanostructured thermoelectric materials

Abstract: High values of thermoelectric figures of merit ZT, ranging from ZT=1.6 at 300 K to ZT=3 at 550 K, are reported for Bi-doped n-type PbSeTe/PbTe quantum-dot superlattice (QDSL) samples grown by molecular beam epitaxy (MBE). These ZT values were determined by directly measuring Seebeck coefficients and electrical conductivities and using the low lattice thermal conductivity value (∼3.3 mW/cm-K) determined experimentally from measurements of a one-legged thermoelectric cooler. Initial experiments have also shown that high values of ZT (∼1.1 at 300 K) are achievable for complementary Na-doped p-type PbSeTe/PbTe QDSL samples, in which the conduction and valence bands mirror those in the Bi-doped Pb chalcogenides.

Thermopower enhancement in PbTe with Pb precipitates

Abstract: The thermoelectric power of polycrystalline PbTe samples containing nanometer-sized precipitates of Pb metal is enhanced over that of bulk PbTe. Samples of PbTe containing excess Pb and Ag were prepared using conventional metallurgical heat treatments. These samples are shown, by x-ray diffraction, by microscopy, and by the presence of a superconductive transition, to contain Pb precipitates with sizes on the order of 30–40nm. The thermopower enhancement is related to an increase in the energy dependence of the relaxation time, as evidenced by a complete set of measurements of thermoelectric and thermomagnetic transport coefficients.

Large thermoelectric performance of heavily Nb-doped SrTiO3 epitaxial film at high temperature

Abstract: Carrier concentration dependence of the thermoelectric figure of merit, ZT of SrTiO3 at high-temperature (1000 K) is clarified using heavily Nb-doped SrTiO3 epitaxial films, which were grown on insulating (100)-oriented LaAlO3 single-crystalline substrates by a pulsed-laser deposition method. Carrier concentration, Hall mobility, Seebeck coefficient, and thermal conductivity of Nb-doped SrTiO3 epitaxial films were experimentally evaluated at 1000 K with an aid of theoretical analysis. ZT of Nb-doped SrTiO3 increases with Nb concentration and it reaches ∼0.37 (20% Nb doped), which is the largest value among n-type oxide semiconductors ever reported.

Thermoelectric properties of Bi-doped Mg2Si semiconductors

Abstract: The thermoelectric properties of Bi-doped Mg2Si (Mg2Si:Bi=1:x) fabricated by spark plasma sintering process have been characterized by Hall effect measurements at 300 K and by measurements of electrical resistivity ( ρ ) , Seebeck coefficient (S), and thermal conductivity ( κ ) between 300 and 900 K. Bi-doped Mg2Si samples are n-type in the measured temperature range. The electron concentration of Bi-doped Mg2Si at 300 K ranges from 1.8×1019 cm−3 for the Bi concentration x = 0.001 to 1.1×1020 cm−3 for x = 0.02 . The solubility limit of Bi in Mg2Si is estimated to be about 1.3 at% and first-principles calculation revealed that Bi atoms are expected to be primarily located at the Si sites in Mg2Si. The electrical resistivity, Seebeck coefficient, and thermal conductivity are strongly affected by the Bi concentration. The sample of x = 0.02 shows a maximum value of the figure of merit, ZT, is 0.86 at 862 K.

Thermopower Enhancement in PbTe with Pb Precipitates

Abstract: The thermoelectric power of polycrystalline PbTe samples containing nanometer-sized precipitates of Pb metal is enhanced over that of bulk PbTe. Samples of PbTe containing excess Pb and Ag were prepared using conventional metallurgical heat treatments. These samples are shown, by x-ray diffraction, by microscopy, and by the presence of a superconductive transition, to contain Pb precipitates with sizes on the order of 30–40nm. The thermopower enhancement is related to an increase in the energy dependence of the relaxation time, as evidenced by a complete set of measurements of thermoelectric and thermomagnetic transport coefficients.

Ag9TlTe5: A high-performance thermoelectric bulk material with extremely low thermal conductivity

Abstract: We studied a high-performance thermoelectric material whose chemical formula is Ag9TlTe5. Ag9TlTe5 is simple and easy to prepare. Its highest dimensionless figure of merit (ZT) value is 1.23, obtained at 700K. The values of individual thermoelectric properties at 700K are 2.63×10−4Ωm for electrical resistivity, 319μVK−1 for Seebeck coefficient, and 0.22Wm−1K−1 for thermal conductivity. Ag9TlTe5 is a unique material combining extremely low thermal conductivity and relatively low electrical resistivity.

High performance n-type PbTe-based materials for thermoelectric applications

Abstract: Lead telluride-based compounds are known for their favorable thermoelectric properties in the 50–600 °C temperature range. The transport properties of homogeneous, cold-compacted and sintered PbI 2 -doped PbTe samples were measured and compared to those of cast samples with similar dopant concentrations. Such a comparison is mandatory in order to determine the potential of graded samples, prepared by powder metallurgy, for thermoelectric applications. The present work focuses on improving the thermoelectric efficiency of PbTe-based materials by functional grading and by taking advantage of the specific features of indium as dopant element. The potential for achieving high thermoelectric efficiency in In-doped n-type PbTe-based thermoelectric compounds is described, and is compared to that of PbI 2 -doped PbTe. Design, synthesis and characterization procedures are reported for fabricating In- and PbI 2 -doped PbTe compounds with desired composition profiles.

Thermoelectric properties of individual electrodeposited bismuth telluride nanowires

Abstract: For an electrodeposited bismuth telluride (BixTe1−x) nanowire from one batch with x found to be about 0.46, the Seebeck coefficient (S) was measured to be 15%–60% larger than the bulk values at temperature 300K. For four other nanowires from a different batch with x≈0.54, S was much smaller than the bulk values. The electrical conductivity of the nanowires showed unusually weak temperature dependence and the values at 300K were close to the bulk values. Below 300K, phonon-boundary scattering dominated phonon-phonon Umklapp scattering in the nanowires, reducing the lattice thermal conductivity.

Electronic Properties of Amorphous and Crystalline Ge2Sb2Te5 Films

Abstract: Optical and electrical properties of sputtered Ge2Sb2Te5 films in amorphous and crystalline states have been studied. The optical band-gaps of amorphous, cubic (NaCl-type), and hexagonal Ge2Sb2Te5 are 0.74, 0.5, and 0.5 eV, respectively. Electrically, the amorphous and cubic states behave as semiconductors with activation energies of 0.45 and 0.14 eV, while the hexagonal state is metallic. The resistivity decreases slightly at the melting point of ~600°C. All the states show p-type thermoelectric power, in which the amorphous and the cubic state have the activation energies of 0.3 and 0.14 eV. Carrier parameters and electronic densities-of-states are estimated and considered.

Transport in doped skutterudites: Ab initio electronic structure calculations

Abstract: We present ab initio calculations of conductivity, thermopower, Lorenz factor, and Hall coefficient for doped cobalt antimony skutterudites which are currently investigated experimentally for their thermoelectric properties. The electronic structure is calculated by the full potential linear augmented-plane-wave method. Using the results and shifting the Fermi level in a rigid way to mimic doping, Onsager coefficients are calculated in the framework of Boltzmann transport theory with a constant relaxation time. To this end electron velocities are calculated using a spectral collocation method. These results compare favorably with experiments.

Enhanced thermoelectric performance in PbTe-based superlattice structures from reduction of lattice thermal conductivity

Abstract: We have fabricated two-dimensional n-type PbTe∕PbTe0.75Se0.25 structures using an evaporation process. In optimized films exhibiting a high-quality superlattice structure, a significant reduction in lattice thermal conductivity has been experimentally measured. The reduction would indicate enhanced thermoelectric device performance compared to standard PbTeSe alloys given that the electrical components, specifically, the Seebeck coefficient and electrical resistivity, were not observed to deteriorate from bulk values. The analysis of these films shows continuous layers with a true two-dimensional superlattice structure, as opposed to the PbTe∕PbSe system that exhibits zero-dimensional structures from self-assembly. The room-temperature measurement of cross-plane figure-of-merit in a n-type PbTe∕PbTe0.75Se0.25 device structure by the transient method has been combined with temperature-dependent measurements of in-plane resistivity and Seebeck coefficient to yield evidence of enhanced thermoelectric perform...

Structural, optical and electrical properties of chemically sprayed CdO thin films

Abstract: The cadmium oxide (CdO) thin films have been deposited onto amorphous and fluorine doped tin oxide (FTO) glass substrates using spray pyrolysis technique. The aqueous solution containing precursor of Cd has been used to obtain good quality deposits at optimized preparative parameters. The films have been characterized by techniques such as X-ray diffraction (XRD), optical absorption, electrical resistivity and thermoelectric power (TEP) measurements. The XRD study reveals that the films are polycrystalline with cubic structure. Optical absorption studies reveal that the value of absorption coefficient is in the order of 10 4 cm −1 , indicating direct band to band transition with band gap energy 2.26 eV, close to its value of intrinsic band gap energy. The electrical characterization shows that the electrical resistivity ( ρ ) is of the order 10 −3 Ω cm and it decreases with increase in temperature indicate the samples are semiconducting in nature. The value of activation energy is found to be 0.077 eV. TEP measurement shows the thermoelectric voltage for CdO films is positive towards the hot end, indicating n-type behavior of sample. The value of TEP increases with increase in temperature. The Hall effect measurement study reveals that the carrier concentration ( n ), Hall coefficients ( R H ) and carrier mobility ( μ H ) are of the order of 10 23 cm −3 , 10 −8 cm 3 /C and 10 −4 cm −2 /V s, respectively.

Thermoelectric power factor in semiconductors with buried epitaxial semimetallic nanoparticles

Abstract: We have grown composite epitaxial materials that consist of semimetallic ErAs nanoparticles embedded in a semiconducting In0.53Ga0.47As matrix both as superlattices and randomly distributed throughout the matrix. The presence of these particles increases the free electron concentration in the material while providing scattering centers for phonons. We measure electron concentration, mobility, and Seebeck coefficient of these materials and discuss their potential for use in thermoelectric power generators.

Theoretical studies on the thermopower of semiconductors and low-band-gap crystalline polymers

Abstract: A numerical procedure has been used for the prediction of the Seebeck coefficient of a crystalline material based on its electronic band structure with the goal of testing this approach on the simple polymers polythiophene and polyaminosquaraine. The investigation of several representative materials, including the crystalline solids $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Zn}}_{4}{\mathrm{Sb}}_{3}$ and $\mathrm{Au}{\mathrm{In}}_{2}$ and these polymers, under ambient or external pressure conditions, indicates that Seebeck coefficients can be calculated within the rigid-band and constant-relaxation-time approximations. The results are in semiquantitative agreement with experiment and provide a basic understanding of the mechanisms for thermopower. These theoretical results together with previous similar studies show that band-structure calculations can be used to guide the rational design of high-performance thermoelectric materials. We also suggest that appropriate and specially engineered doped low-band-gap polymers may be promising candidate materials for thermoelectric applications.

Low-temperature solubility of copper in iron: experimental study using thermoelectric power, small angle X-ray scattering and tomographic atom probe

Abstract: Measuring the solubility limit of copper in iron at temperature lower than 700°C is problematic because copper diffusion is too slow in this temperature range. To overcome this difficulty, fine precipitation of copper is studied. The solubility limit of copper is measured after complete precipitation using two complementary techniques: thermoelectric power and small angle X-ray scattering. Values obtained are confirmed by tomographic atom probe and give results much higher than what is usually extrapolated from high-temperature experiments.

Thermoelectric properties of Te-doped CoSb3 by spark plasma sintering

Abstract: Te-doped CoSb3 bulk polycrystalline materials Co4Sb12−xTex have been prepared by melting, annealing, and spark plasma sintering and have been characterized by x-ray diffraction. From the lattice constants of the Te-doped samples, a Te substituting fraction limit for Sb is estimated to be x=0.55. The Hall effect, Seebeck coefficient, electrical-conductivity, and thermal-conductivity measurements were performed between room temperature and 900K. The Te-doped materials Co4Sb12−xTex show an n-type conduction. As the Te fraction increases, the electron concentration and the electrical conductivity of the samples increase, while the Hall mobility, the absolute Seebeck coefficient, and the thermal conductivity decrease. A maximum dimensionless figure of merit of 0.72 is obtained at 850K for Co4Sb11.5Te0.5.

Thermoelectric performance of films in the bismuth-tellurium and antimony-tellurium systems

Abstract: Coevaporated bismuth-tellurium and antimony-tellurium films were fabricated under various deposition conditions (controlled evaporation rates of individual species, substrate temperature, and substrate material), and their thermoelectric (TE) properties (Seebeck coefficient, electrical resistivity, and carrier concentration) were measured in search of optimal TE performance. The tellurium atomic concentration was varied from 48% to 74%, the substrate temperature ranged from 130 to 300 °C, and glass, mica, magnesium oxide, and sapphire substrates were used. The chemical composition and crystal structure of the films were recorded (using microprobe and x-ray diffractometer, respectively), analyzed, and compared with available standard Bi2Te3 and Sb2Te3 single-crystal samples. High-performance TE films had tellurium atomic concentration around 60% and were deposited at a substrate temperature between 260 and 270 °C.

Microstructural and Thermoelectric Characteristics of Zinc Oxide‐Based Thermoelectric Materials Fabricated Using a Spark Plasma Sintering Process

Abstract: M-doped zinc oxide (ZnO) (M = Al and/or Ni) thermoelectric materials were fully densified at a temperature lower than 1000 C using a spark plasma sintering technique and their microstructural evolution and thermoelectric characteristics were investigated. The addition of Al 2 O 3 reduced the surface evaporation of pure ZnO and suppressed grain growth by the formation of a secondary phase. The addition of NiO promoted the formation of a solid solution with the ZnO crystal structure and caused severe grain growth. The co-addition of Al 2 O 3 and NiO produced a homogeneous microstructure with a good grain boundary distribution. The microstructural characteristics induced by the co-addition of Al 2 O 3 and NiO have a major role in increasing the electrical conductivity and decreasing the thermal conductivity, resulting from an increase in carrier concentration and the phonon scattering effect, respectively, and therefore improving the thermoelectric properties. The ZnO specimen, which was sintered at 1000°C with the co-addition of Al 2 O 3 and NiO, exhibited a ZT value of 0.6 × 10 -3 K -1 , electrical conductivity of 1.7 × 10 -4 Ω -1 . m -1 , the thermal conductivity of 5.16 W . (m . K) -1 , and Seebeck coefficient of 425.4 μV/K at 900 C. The ZT value obtained respects the 30% increase compared with the previously reported value, 0.4 × 10 -3 K -1 , in the literature.

Apparatus for Seebeck coefficient and electrical resistivity measurements of bulk thermoelectric materials at high temperature

Abstract: A high temperature Seebeck coefficient and electrical resistivity measurement apparatus has been designed and built for measuring advanced thermoelectric materials. The apparatus covers the range of temperatures from 300to1300K. Different sources of errors involved in the two measurements are discussed. The accuracy of the electrical resistivity measurement is estimated to be better than ±1% by measuring standard graphite sample from NIST.