scholarly journals High thermoelectric figure of merit of porous Si nanowires from 300 to 700 K

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lin Yang ◽  
Daihong Huh ◽  
Rui Ning ◽  
Vi Rapp ◽  
Yuqiang Zeng ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicon Nanowires ◽  
Figure Of Merit ◽  
Waste Heat ◽  
Si Nanowires ◽  
Large Area ◽  
Thermoelectric Figure ◽  
Zero Carbon ◽  
Porous Silicon Nanowires ◽  
Nanostructured Si

AbstractThermoelectrics operating at high temperature can cost-effectively convert waste heat and compete with other zero-carbon technologies. Among different high-temperature thermoelectrics materials, silicon nanowires possess the combined attributes of cost effectiveness and mature manufacturing infrastructures. Despite significant breakthroughs in silicon nanowires based thermoelectrics for waste heat conversion, the figure of merit (ZT) or operating temperature has remained low. Here, we report the synthesis of large-area, wafer-scale arrays of porous silicon nanowires with ultra-thin Si crystallite size of ~4 nm. Concurrent measurements of thermal conductivity (κ), electrical conductivity (σ), and Seebeck coefficient (S) on the same nanowire show a ZT of 0.71 at 700 K, which is more than ~18 times higher than bulk Si. This ZT value is more than two times higher than any nanostructured Si-based thermoelectrics reported in the literature at 700 K. Experimental data and theoretical modeling demonstrate that this work has the potential to achieve a ZT of ~1 at 1000 K.

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.

Heat Transport in Superlattices and Nanocomposites for Thermoelectric Applications

2006 ◽  
Vol 46 ◽  
pp. 104-110 ◽  
Author(s):  
Gang Chen
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Large Scale ◽  
Energy Transport ◽  
High Efficiency ◽  
Waste Heat ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

Energy transport in nanostructures differs significantly from macrostructures because of classical and quantum size effects on energy carriers. Experimental results show that the thermal conductivity values of nanostructures such as superlattices are significantly lower than that of their bulk constituent materials. The reduction in thermal conductivity led to a large increase in the thermoelectric figure of merit in several superlattice systems. Materials with a large thermoelectric figure of merit can be used to develop efficient solid-state devices that convert waste heat into electricity. Superlattices grown by thin-film deposition techniques, however, are not suitable for large scale applications. Nanocomposites represent one approach that can lead to high thermoelectric figure merit. This paper reviews the current understanding of thermal conductivity reduction mechanisms in superlattices and presents theoretical studies on thermoelectric properties in semiconducting nanocomposites, aiming at developing high efficiency thermoelectric energy conversion materials.

Enhanced thermoelectric performance of GeTe through in situ microdomain and Ge-vacancy control

2019 ◽  
Vol 7 (25) ◽  
pp. 15181-15189 ◽  
Author(s):  
Khasim Saheb Bayikadi ◽  
Raman Sankar ◽  
Chien Ting Wu ◽  
Chengliang Xia ◽  
Yue Chen ◽  
...  
Keyword(s):  
High Temperature ◽  
Figure Of Merit ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Vacancy Level

The thermoelectric figure-of-merit (ZT) for GeTe powder is able to be raised from ∼0.8 to 1.37 at high temperature near ∼500 °C by tuning the Ge vacancy level through a reversible in situ route.

Elaboration of Core Si/Shell SiC Nanowires

2013 ◽  
Vol 740-742 ◽  
pp. 306-310
Author(s):  
Maelig Ollivier ◽  
Laurence Latu-Romain ◽  
Arnaud Mantoux ◽  
Mickaël Martin ◽  
Thierry Baron ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicon Nanowires ◽  
Atmospheric Pressure ◽  
Seed Layer ◽  
Si Nanowires ◽  
Protective Shell ◽  
Top Down ◽  
Preferential Growth ◽  
Sic Nanowires ◽  
Sem And Tem

Silicon nanowires obtained by a top-down approach have been carburized at high temperature and atmospheric pressure with two different gaseous precursors: CH4 and C3H8. These processes reveal core silicon / shell 3C-SiC nanowires. After being characterized by SEM, FIB-SEM and TEM microscopies, the 3C-SiC layer has been used as seed layer for the growth of epitaxial 3C-SiC on the nanowires. Preferential growth of 3C-SiC on the sidewalls of nanowires has been observed. Thanks to the biocompatibility of SiC compared to Si, this layer could act as a protective shell for biosensors based on Si nanowires transistor.

Optimization of High Thermoelectric Figure-of-Merit in p-type Ag1-x(Pb1-ySny)mSb1-zTem+2

2007 ◽  
Vol 1044 ◽  
Author(s):  
Kyunghan Ahn ◽  
Mercouri G Kanatzidis
Keyword(s):  
High Temperature ◽  
Thermoelectric Properties ◽  
High Performance ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Practical Applications ◽  
P Type

AbstractThe Ag1-x(Pb1-ySny)mSb1-zTem+2 compounds have been found to exhibit high performance p-type thermoelectric properties and are now being considered for practical applications. In this paper, various m values and silver concentrations were investigated to determine the effect on thermoelectric properties. Also, the charge-compensated compounds were studied in order to eliminate the problem of excess tellurium evaporation at high temperature.

scholarly journals Tuning the fluorescence intensity and stability of porous silicon nanowires via mild thermal oxidation

RSC Advances ◽  
2017 ◽  
Vol 7 (55) ◽  
pp. 34579-34583 ◽  
Author(s):  
Lu Gan ◽  
Haiping He ◽  
Qianqian Yu ◽  
Zhizhen Ye
Keyword(s):  
Porous Silicon ◽  
Thermal Oxidation ◽  
Fluorescence Intensity ◽  
Silicon Nanowires ◽  
Luminescence Quenching ◽  
Porous Si ◽  
Si Nanowires ◽  
Porous Silicon Nanowires

Porous Si nanowires show anomalous luminescence quenching and improved sensing stability upon mild thermal oxidation.

Thermoelectric properties of (Bi,Pb)–Sr–Co–O oxide

2000 ◽  
Vol 15 (2) ◽  
pp. 382-386 ◽  
Author(s):  
Woosuck Shin ◽  
Norimitsu Murayama
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Single Crystal ◽  
Figure Of Merit ◽  
Polycrystalline Sample ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Sinter Forging ◽  
Thermoelectric Application

Electrical conductivity and thermopower of Bi2Sr3Co2Ox sintered bodies were first investigated in the temperature range 440–1060 K in air for high-temperature thermoelectric application. The samples fabricated by the sinter-forging method increased their bulk densities and electrical conductivity. The value of thermopower and the temperature dependence of electrical conductivity of the sinter-forged samples were close to that of the single crystal. Evaluating the thermal conductivity of the polycrystalline sample, we calculated a thermoelectric figure of merit Z to be 0.107 × 10−3 K−1 at 1060 K.

scholarly journals n-type thermoelectric material Mg2Sn0.75Ge0.25 for high power generation

2015 ◽  
Vol 112 (11) ◽  
pp. 3269-3274 ◽  
Author(s):  
Weishu Liu ◽  
Hee Seok Kim ◽  
Shuo Chen ◽  
Qing Jie ◽  
Bing Lv ◽  
...  
Keyword(s):  
Power Generation ◽  
Output Power ◽  
High Power ◽  
Figure Of Merit ◽  
High Efficiency ◽  
Waste Heat ◽  
Flow Equation ◽  
Thermoelectric Figure ◽  
One Dimensional ◽  
High Power Factor

Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg2Sn-based material, Mg2Sn0.75Ge0.25, is a good example to meet the dual requirements in efficiency and output power. It was found that Mg2Sn0.75Ge0.25 has an average ZT of 0.9 and PF of 52 μW⋅cm−1⋅K−2 over the temperature range of 25–450 °C, a peak ZT of 1.4 at 450 °C, and peak PF of 55 μW⋅cm−1⋅K−2 at 350 °C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with Th = 400 °C and Tc = 50 °C to be of 10.5% and 6.6 W⋅cm−2 under a temperature gradient of 150 °C⋅mm−1, respectively.

scholarly journals Realizing a 14% single-leg thermoelectric efficiency in GeTe alloys

2021 ◽  
Vol 7 (19) ◽  
pp. eabf2738
Author(s):  
Zhonglin Bu ◽  
Xinyue Zhang ◽  
Bing Shan ◽  
Jing Tang ◽  
Hongxia Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Figure Of Merit ◽  
High Efficiency ◽  
Phonon Scattering ◽  
Waste Heat ◽  
Chemical Diffusion ◽  
Thermoelectric Device ◽  
Thermoelectric Efficiency ◽  
Good Service ◽  
Thermoelectric Figure

GeTe alloys have recently attracted wide attention as efficient thermoelectrics. In this work, a single-leg thermoelectric device with a conversion efficiency as high as 14% under a temperature gradient of 440 K was fabricated on the basis of GeTe-Cu2Te-PbSe alloys, which show a peak thermoelectric figure of merit (zT) > 2.5 and an average zT of 1.8 within working temperatures. The high performance of the material is electronically attributed to the carrier concentration optimization and thermally due to the strengthened phonon scattering, the effects of which all originate from the defects in the alloys. A design of Ag/SnTe/GeTe contact successfully enables both a prevention of chemical diffusion and an interfacial contact resistivity of 8 microhm·cm2 for the realization of highly efficient devices with a good service stability/durability. Not only the material’s high performance but also the device’s high efficiency demonstrated the extraordinariness of GeTe alloys for efficient thermoelectric waste-heat recovery.

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