Thermoelectric Power Measurement of Catalyst-free Si-doped GaAs Nanowires

2012 ◽  
Vol 1439 ◽  
pp. 83-87 ◽  
Author(s):  
Masahito Yamaguchi ◽  
Jihyun Paek ◽  
Hiroshi Amano
Keyword(s):  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Power Measurement ◽  
Hole Density ◽  
Thermoelectric Power Factor ◽  
Gaas Nanowires ◽  
Thermoelectric Power Measurement ◽  
Si Doped

ABSTRACTSi-doped GaAs nanowires (NWs) were grown on (111)Si substrate by MBE-VLS method. The electrical characteristics of the GaAs NWs were measured. A joule heater was arranged near the tip of NW for making the gradient of substrate temperature. The obtained Seebeck coefficient of the GaAs NW increases linearly with a rise in temperature. The thermoelectric power of the Si doped GaAs NW was determined by the hole diffusion. It was estimated that the hole density in the Si-doped GaAs NW at room temperature was 5.9×1018 cm-3 from the slope of the temperature dependence of the Seebeck coefficient in the Si-doped GaAs NW. At room temperature, the Seebeck coefficient, thermoelectric power factor, and thermoelectric figure of merit (ZT) were 429 μV/K, 271μW/mK2, and 1.5×10-3, respectively.

The Influence of Silicon Dopant and Processing on Thermoelectric Properties of B4C Ceramics

1998 ◽  
Vol 545 ◽  
Author(s):  
Ke-Feng Cai ◽  
Ce-Wen Nan ◽  
Xin-Min Min
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Room Temperature ◽  
A Value ◽  
Si Doped

AbstractB4C ceramics doped with various content of Si (0 to 2.03 at%) are prepared via hot pressing. The composition and microstructure of the ceramics are characterized by means of XRD and EPMA. Their electrical conductivity and Seebeck coefficient of the samples are measured from room temperature up to 1500K. The electrical conductivity increases with temperature, and more rapidly after 1300K; the Seebeck coefficient of the ceramics also increases with temperature and rises to a value of about 320μVK−1. The value of the figure of merit of Si-doped B4C rises to about 4 × 10−4K−1 at 1500K.

Synthesis and Thermoelectric Studies in Cr Doped Cobalt Ferrites Nano Particles

2012 ◽  
Vol 510-511 ◽  
pp. 171-176 ◽  
Author(s):  
M. Anis-ur-Rehman ◽  
Mariam Ansari ◽  
Zeb Un Nisa Mughal ◽  
M.S. Awan ◽  
Ashari Maqsood
Keyword(s):  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Room Temperature ◽  
Nano Particles ◽  
Power Measurement ◽  
Cobalt Ferrites ◽  
Before And After ◽  
Crystallite Sizes ◽  
Xrd Patterns ◽  
Co Precipitation

Samples of Cr doped cobalt ferrite were prepared by co-precipitation route. These particles were characterized by X-ray diffraction (XRD) at room temperature. The structural properties were observed before and after sintering. The FCC spinel structure was confirmed by XRD patterns of the samples. The crystallite sizes lie in the range of 37-60 nm. DC electrical properties as a function composition were measured. Scanning electron microscopy was used in order to investigate the surface morphology of the prepared samples. The system for thermoelectric power measurement was designed, developed and calibrated in the laboratory. The room temperature thermoelectric power was measured for the prepared samples. The magnitude of Seebeck coefficient depends on the composition and resistivity of the samples. The obtained values of Seebeck coefficient for CoFe2O4are in good agreement to the reported values. Determined values of Seebeck coefficient for other studied compositions are an addition to the literature.

Thermoelectric Power Factor of Polycrystalline La0.75Sr0.25Co1-xMnxO3-δCeramics

2009 ◽  
Vol 1166 ◽  
Author(s):  
Julio E. Rodríguez ◽  
J. A. Niño
Keyword(s):  
Transport Properties ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Manganese Content ◽  
Solid State Reaction Method ◽  
Measured Temperature ◽  
Thermoelectric Power Factor ◽  
Temperature Range

AbstractThermoelectric properties of polycrystalline La0.75Sr0.25Co1-xMnxO3-δ(0<x<0.08) (LSCoO-Mn) compounds have been studied. The samples were grown by solid-state reaction method; their transport properties were studied in the temperature range between 100 and 290K, as a function of temperature and the manganese content. The Seebeck coefficient (S) is positive over the measured temperature range and its magnitude increases with the manganese content up to values close to 160 μV/K. The electrical resistivity (ρ) goes from metallic to semiconducting behavior as the Mn level increases, at room temperature, ρ(T) exhibit values less than 4mΩ-cm. From S(T), ρ(T) and κ(T) data, the thermoelectric power factor and the figure of merit were determined. These performance parameters reach maximum values around 18 μW/K2-cm and 0.2, respectively. The observed behavior in the transport properties become these compounds potential thermoelectric materials, which could be used in thermoelectric applications.

PHONON-DRAG EFFECT OF ULTRA-THIN FeSi2 AND MnSi1.7/FeSi2 FILMS

2011 ◽  
Vol 25 (22) ◽  
pp. 1829-1838 ◽  
Author(s):  
Q. R. HOU ◽  
B. F. GU ◽  
Y. B. CHEN ◽  
Y. J. HE
Keyword(s):  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Single Crystals ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Low Temperatures ◽  
Room Temperature ◽  
Phonon Drag ◽  
Drag Effect ◽  
Thermoelectric Power Factor

Phonon-drag effect usually occurs in single crystals at very low temperatures (10–200 K). Strong phonon-drag effect is observed in ultra-thin β- FeSi 2 films at around room temperature. The Seebeck coefficient of a 23 nm-thick β- FeSi 2 film can reach -1.375 mV/K at 343 K. However, the thermoelectric power factor of the film is still small, only 0.42×10-3 W/m-K2, due to its large electrical resistivity. When a 27 nm-thick MnSi 1.7 film with low electrical resistivity is grown on it, the thermoelectric power factor of the MnSi 1.7 film can reach 1.5×10-3 W/m-K2 at around room temperature. This value is larger than that of bulk MnSi 1.7 material in the same temperature range.

Enhancement of Thermopower due to Deficiency of Sb in FeSb2

2013 ◽  
Vol 665 ◽  
pp. 179-181 ◽  
Author(s):  
Anup V. Sanchela ◽  
Varun Kushwaha ◽  
Ajay. D. Thakur ◽  
C.V. Tomy
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Low Temperatures ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Parent Compound ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Thermoelectric Power Factor ◽  
Anomalous Peak

FeSb2 was recently found to be a narrow-gap semiconductor with strong electronelectron correlation and a large thermopower at low temperatures. We report measurements of the electrical resistivity, Seebeck coefficient and thermal conductivity between 5 K to 300 K on polycrystalline samples of FeSb2 and FeSb1.9. We found that the deficiency of Sb in the parent compound leads to a giant anomalous peak in thermopower (S) at low temperatures, reaching ~ 426 μV/K at 20 K, resulting in a high thermoelectric power factor at low temperatures, achieving 10 μW/K2m at 27 K.. Consequently, a significantly enhanced thermoelectric figure of merit ZT ~ 0.0015 is achieved near room temperature. At low temperatures there is no improvement in ZT values due to the high thermal conductivity (phonon dominant region). Keywords: Seebeck coefficient, thermal conductivity, resistivity, thermoelectric figure of merit. PACS: 72.20.Pa, 71.27.+a, 71.28.+d

Improved Thermoelectric Properties of SixGe1−x by the “Nanoparticle-in-Alloy” Approach

2009 ◽  
Author(s):  
Shidong Wang ◽  
Natalio Mingo
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Power ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Waste Heat ◽  
Fold Increase ◽  
Thermoelectric Power Factor ◽  
Figures Of Merit

We theoretically find that embedding silicide nanoparticles in SixGe1-x alloys is able to considerably improve the figure of merit (ZT). We have computed the thermal conductivity as a function of the sizes of NiSi2 and CoSi2 nanoparticles. We find that the optimal nanoparticle diameters minimizing the composite’s thermal conductivity are 6.9 nm for NiSi2 and 12.6 nm for CoSi2 at room temperature. We provide validity ranges of nanoparticle volume fractions that will not reduce the thermoelectric power factor, but will considerably decrease the thermal conductivity. Embedding NiSi2 or CoSi2 nanoparticles in SixGe1-x may lead to a 5-fold increase of figure of merit (ZT ∼ 0.5) at room temperature and 2.8 times increase (ZT ∼ 2.0) at 900 K. The proposed materials with high figures of merit are promising candidates to be used in integrated micro refrigerators in chips and thermoelectric power generation and waste heat recovery.

Synthesis and thermoelectric power factor of LSCO perovskites

2005 ◽  
Vol 886 ◽  
Author(s):  
Julio E. Rodriguez
Keyword(s):  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Power Factor ◽  
Room Temperature ◽  
Morphological Properties ◽  
Measured Temperature ◽  
X Ray Diffraction ◽  
Thermoelectric Power Factor ◽  
X Ray

ABSTRACTMeasurements of Seebeck coefficient, S(T) and electrical resistivity, ρ(T) on polycrystalline La2−xSrxCuO4+d(LSCO) (0<x≤0.2) samples are reported. The Seebeck coefficient is positive in whole measured temperature range (77K and 300K) and it decreases with Sr content. At room temperature S(T) changes from 400 μ/K for the samples with the lowest levels of Sr to 30 μV/K for the samples with the highest Sr levels. The behavior of S(T) fits to Heikes model, which describes the behavior of Seebeck coefficient in systems where the correlated hopping is present. With the Sr content, the electrical resistivity changes its behavior from semiconducting to metallic and it took values from 2.4 to 10−3Ωcm. From S(T) and rho(T) measurements the thermoelectric power factor, PF was obtained. The maximum values for PF were about 5 μW/K2cm in the samples where x= 0.03, which are comparable to the typical values for conventional thermoelectric semiconductors. The structural and morphological properties of the samples were studied by x-ray diffraction analysis and Scanning Electron Microscopy (SEM) respectively. The behavior of transport properties opens de possibility of considering this family of perovskite-compounds as a thermoelectric material which works below room temperature.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

scholarly journals Preparation of InSe Thin Films by Thermal Evaporation Method and Their Characterization: Structural, Optical, and Thermoelectrical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Sarita Boolchandani ◽  
Subodh Srivastava ◽  
Y. K. Vijay
Keyword(s):  
Thin Films ◽  
Seebeck Coefficient ◽  
Thermoelectric Power ◽  
Temperature Variation ◽  
Thermal Evaporation ◽  
Low Cost ◽  
High Vacuum ◽  
Power Measurement ◽  
Thermal Evaporation Method ◽  
Evaporation Method

The indium selenium (InSe) bilayer thin films of various thickness ratios, InxSe(1-x) (x = 0.25, 0.50, 0.75), were deposited on a glass substrate keeping overall the same thickness of 2500 Ǻ using thermal evaporation method under high vacuum atmosphere. Electrical, optical, and structural properties of these bilayer thin films have been compared before and after thermal annealing at different temperatures. The structural and morphological characterization was done using XRD and SEM, respectively. The optical bandgap of these thin films has been calculated by Tauc’s relation that varies within the range of 1.99 to 2.05 eV. A simple low-cost thermoelectrical power measurement setup is designed which can measure the Seebeck coefficient “S” in the vacuum with temperature variation. The setup temperature variation is up to 70°C. This setup contains a Peltier device TEC1-12715 which is kept between two copper plates that act as a reference metal. Also, in the present work, the thermoelectric power of indium selenide (InSe) and aluminum selenide (AlSe) bilayer thin films prepared and annealed in the same way is calculated. The thermoelectric power has been measured by estimating the Seebeck coefficient for InSe and AlSe bilayer thin films. It was observed that the Seebeck coefficient is negative for InSe and AlSe thin films.

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