Thermoelectric Properties of Ge-doped Cu3SbSe4

2011 ◽  
Vol 1314 ◽  
Author(s):  
Eric J. Skoug ◽  
Jeffrey D. Cain ◽  
Donald T. Morelli
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
State Of The Art ◽  
Unit Cell ◽  
Large Hole ◽  
Hole Effective Mass ◽  
Large Unit ◽  
Ternary Semiconductor ◽  
Large Unit Cell ◽  
P Type

ABSTRACTTernary variations of the II-VI zincblende semiconductors have received little attention for thermoelectric applications. Here we present the first systematic doping study on Cu3SbSe4, a zincblende-like ternary semiconductor with a unit cell four times larger than the parent II-VI compounds. The large unit cell of Cu3SbSe4 results in a low room temperature thermal conductivity (~3.0 W/m*K) and its large hole effective mass produces a Seebeck coefficient approaching 500 μV/K in the undoped compound. Our results show that Ge is an effective p-type dopant in Cu3SbSe4, and the power factor reaches nearly 16 μW/cm*K2 at 630K when 3% Ge is added, rivaling that of state-of-the-art thermoelectric materials at this temperature.

Thermoelectric Properties of Tl2Te-Sb2Te3 Pseudo-Binary System

2005 ◽  
Vol 886 ◽  
Author(s):  
Ken Kurisaki ◽  
Keita Goto ◽  
Atsuko Kosuga ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Thermal Conductivity ◽  
Binary System ◽  
Thermoelectric Properties ◽  
Room Temperature ◽  
State Of The Art ◽  
Electrical Performance ◽  
Low Thermal Conductivity ◽  
Maximum Value ◽  
P Type ◽  
Type Conduction

ABSTRACTPolycrystalline-sintered samples of thallium based substances, (Tl2Te)100−x(Sb2Te3)x (x= 0, 1, 5, 10), were prepared by melting Tl2Te and Sb2Te3 ingots followed by annealing in sealed quartz ampoules. The thermoelectric properties were measured from room temperature to around 600 K. The values of the Seebeck coefficient of all samples are positive, indicating a p-type conduction characteristic. The maximum value of the power factor is 6.53×10−4 Wm−1K−2 at 591 K obtained for x= 10 (Tl9SbTe6), which is about one order lower than those of state-of-the-art thermoelectric materials. All samples indicate an extremely low thermal conductivity, for example that of Tl2Te is approximately 0.35 Wm−1K−1 from room temperature to around 600 K. Although the electrical performance of the samples is not so good, the ZT value is relatively high due to the extremely low thermal conductivity. The maximum ZT value is 0.42 at 591 K obtained for Tl9SbTe6.

scholarly journals Neutron diffractometer covering protein crystals with large unit cell at J-PARC

2014 ◽  
Vol 70 (a1) ◽  
pp. C1746-C1746
Author(s):  
Kazuo Kurihara ◽  
Katsuaki Tomoyori ◽  
Taro Tamada ◽  
Ryota Kuroki
Keyword(s):  
Cell Volume ◽  
Unit Cell Volume ◽  
Structural Information ◽  
Unit Cell ◽  
Proton Accelerator ◽  
Neutron Guide ◽  
Time Dimension ◽  
Hydrogen Atoms ◽  
Large Unit ◽  
Large Unit Cell

The structural information of hydrogen atoms and hydration waters obtained by neutron protein crystallography is expected to contribute to elucidation of protein function and its improvement. However, many proteins, especially membrane proteins and protein complexes, have larger molecular weight and then unit cells of their crystals have larger volume, which is out of range of measurable unit cell volume for conventional diffractometers. Therefore, our group had designed the diffractometer which can cover such crystals with large unit cell volume (target lattice length: 250 Å). This diffractometer is dedicated for protein single crystals and has been proposed to be installed at J-PARC (Japan Proton Accelerator Research Complex). Larger unit cell volume causes a problem to separate spots closer to each other in spatial as well as time dimension in diffraction images. Therefore, our proposed diffractometer adopts longer camera distance (L2 = 800mm) and selects decoupled hydrogen moderator as neutron source which has shorter pulse width. Under the conditions that L1 is 33.5m, beam divergence 0.40and crystal edge size 2mm, this diffractometer is estimated to be able to resolves spots diffracted from crystals with a lattice length of 220 Å in each axis at d-space of 2.0 Å. In order to cover large neutron detecting area due to long camera distance, novel large-area detector (larger than 300mm × 300mm) with a spatial resolution of better than 2.5mm is under development. More than 40 these detectors plan to be installed, providing the total solid angle coverage of larger than 33%. For neutron guide, ellipsoidal supermirror is considered to be adopted to increase neutron flux at the sample position. The final gain factor of this diffractometer is estimated to be about 20 or larger as compared with BIX-3/4 diffractometers operated in the research reactor JRR-3 at JAEA (Japan Atomic Energy Agency) [1,2].

Thermoelectric Properties of Bi2Te3-ySey Bulk Materials Synthesized by Melting-Grinding Process

2018 ◽  
Vol 773 ◽  
pp. 145-151
Author(s):  
Min Soo Park ◽  
Gook Hyun Ha ◽  
Hye Young Koo ◽  
Yong Ho Park
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermal Characteristics ◽  
Grinding Process ◽  
Alloy Scattering ◽  
Temperature Range ◽  
P Type ◽  
Optimal Effect

The Bi–Te thermoelectric system shows an excellent figure of merit (ZT) near room temperature. Research on increasing the ZT value for n‑type Bi–Te is imperative because the thermoelectric properties of this compound are inferior to those of the p-type material. For this purpose, n-type Bi2Te3-ySey powders with various amounts of Se dopant (0.3 ≤ y ≤ 0.6) were synthesized by a vacuum melting-grinding process to improve the physical properties. The ZT value of the sintered bodies was investigated in the temperature range of 298–423 K with regard to the electrical and thermal characteristics. As the Se content increased, the electrical conductivity decreased owing to a reduction in the carrier concentration, which improved the overall value of ZT. The thermal conductivity clearly decreased as the Se content increased in the temperature range of 298–373 K due to increased alloy scattering, as well as a reduction in the lattice thermal conductivity caused by crystal grain boundary scattering. At room temperature, Bi2Te2.7Se0.3 (y = 0.3) exhibited the highest ZT of 0.85. At increased temperatures, the ZT value was highest for Bi2Te2.55Se0.45 (y = 0.45), indicating that the optimal effect of the Se dopants varies depending on the temperature range.

Thermal Conductivity of Zn4−xCdxSb3 Solid Solutions

1997 ◽  
Vol 478 ◽  
Author(s):  
T. Caillat ◽  
A. Borshchevsky ◽  
J. -P. Fleurial
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
State Of The Art ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Jet Propulsion ◽  
P Type ◽  
Electrical Conductors

Abstractβ-Zn4Sb3 was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy β-Zn4Sb3 with isostructural compounds because of the expected decrease in lattice thermal conductivity. We have grown Zn4−xCdxSb3 crystals with 0.2≤x<1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn4−xCdxSb3 alloys are significantly lower than those measured for β-Zn4Sb3 and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

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