Measurements of the Thermal Conductivity of Individual α-Tetragonal Boron Nanoribbons

2011 ◽  
Author(s):  
Juekuan Yang ◽  
Scott W. Waltermire ◽  
Yang Yang ◽  
Deyu Li ◽  
Xiaoxia Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Silicon Nanowires ◽  
Complex Structures ◽  
One Dimensional ◽  
Seebeck Coefficients ◽  
Electrical Conductivities ◽  
Mechanical Devices ◽  
Property Characterization

Boron-based materials (i.e., boron and its borides) are mostly semiconductors with complex structures. These structures are characterized by an arrangement of an icosahedral cluster of B12 atoms [1]. The complexity of the crystal structure gives boron-based material a high melting point and low thermal conductivity at high temperature. On the other hand, the Seebeck coefficients and electrical conductivities of most bulk boron-based materials increase as temperature increases. Therefore, bulk boron-based materials are good candidates for high-temperature thermoelectric applications [2]. Due to the unique properties of bulk boron-based materials, one-dimensional nanostructures of boron-based materials have also attracted much attention, and various boron-based nanostructures have been synthesized recently [3]. These boron-based nanostructures are projected to be promising materials for novel nanoelectronic and nanoelectro-mechanical devices, as well as high temperature thermoelectric materials. However, compared to the extensive studies of carbon nanotubes and silicon nanowires, little has been done on the property characterization of boron and boride nanostructures.

Silicide/Silicon Hetero-Junction Structure for Thermoelectric Applications

2015 ◽  
Vol 15 (10) ◽  
pp. 7472-7475 ◽  
Author(s):  
Dongsuk Jun ◽  
Soojung Kim ◽  
Wonchul Choi ◽  
Junsoo Kim ◽  
Taehyoung Zyung ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Electrical Energy ◽  
Multilayered Structure ◽  
Thermoelectric Device ◽  
Cmos Process ◽  
Platinum Silicide ◽  
Seebeck Coefficients ◽  
Heating And Cooling ◽  
Electrical Conductivities

We fabricated silicide/silicon hetero-junction structured thermoelectric device by CMOS process for the reduction of thermal conductivity with the scatterings of phonons at silicide/silicon interfaces. Electrical conductivities, Seebeck coefficients, power factors, and temperature differences are evaluated using the steady state analysis method. Platinum silicide/silicon multilayered structure showed an enhanced Seebeck coefficient and power factor characteristics, which was considered for p-leg element. Also, erbium silicide/silicon structure showed an enhanced Seebeck coefficient, which was considered for an n-leg element. Silicide/silicon multilayered structure is promising for thermoelectric applications by reducing thermal conductivity with an enhanced Seebeck coefficient. However, because of the high thermal conductivity of the silicon packing during thermal gradient is not a problem any temperature difference. Therefore, requires more testing and analysis in order to overcome this problem. Thermoelectric generators are devices that based on the Seebeck effect, convert temperature differences into electrical energy. Although thermoelectric phenomena have been used for heating and cooling applications quite extensively, it is only in recent years that interest has increased in energy generation.

Erbium boride composites with high ZT values at 800 K

2013 ◽  
Vol 1490 ◽  
pp. 41-44
Author(s):  
Frederick C. Stober ◽  
Barbara R. Albert
Keyword(s):  
High Temperature ◽  
Energy Conversion ◽  
Single Phase ◽  
Rietveld Analysis ◽  
Molar Ratio ◽  
Refractory Materials ◽  
Solid Reaction ◽  
Seebeck Coefficients ◽  
Electrical Conductivities ◽  
Multi Phase

ABSTRACTSingle phase erbium borides ErB2, ErB4, and ErB12 show Seebeck coefficients and power factors with absolute values that are significantly lower than those of a stable Er-B multi phase composite obtained through high temperature solid-solid reaction from the elements (molar ratio Er:B = 1:6). According to quantitative Rietveld analysis the composite consists of erbium diboride (1 %), tetraboride (83 %), and dodecaboride (16 %), and the measurement of the electrical conductivities, Seebeck coefficients, and thermal conductivities leads to ZT values as high as 0.53 at 830 K. Such refractory materials can be used for energy conversion in a range of high temperatures that are otherwise difficult to address.

Simultaneous Measurements of Thermal Conductivity and Seebeck Coefficients of Roughened Nanowire Arrays

2012 ◽  
Vol 1456 ◽  
Author(s):  
J. S. Sadhu ◽  
T. Hongxiang ◽  
J. Ma ◽  
J. Kim ◽  
S. Sinha
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Silicon Nanowires ◽  
Nanowire Array ◽  
Temperature Drop ◽  
Nanowire Arrays ◽  
Measured Temperature ◽  
Si Substrates ◽  
Seebeck Coefficients ◽  
Simultaneous Measurements

ABSTRACTWe report simultaneous measurements of thermal conductivity and Seebeck coefficient on array-scale silicon nanowires fabricated by metal assisted chemical etching. The measurements are conducted on the solid and the mesoporous nanowire arrays (NWAs) obtained from etching 1 ohm-cm and 0.002 ohm-cm Si substrates respectively. We demonstrate control on sidewall morphology and doping of the arrays that have an aspect ratio up to 20 and 30 % areal coverage. We employ differential frequency-domain measurements, separately on the array and the corresponding substrate to obtain the temperature drop and Seebeck voltage contribution of the nanowire array. The technique is validated by measurements on bulk silicon across the resistivity 0.002-1 ohm-cm. The Seebeck measurements reveal quenching of the phonon drag in the nanowires in comparison to the bulk in the measured temperature range of 300 K- 500 K. The Seebeck coefficient shows a ~18 % decrease in the solid NWAs and ~22 % increase in the mesoporous NWAs at room temperature. The thermal conductivity is close to Casimir limit for the solid wires while it drops to ~2.5 W/mK in the mesoporous nanowires.

scholarly journals Enhanced Thermoelectric Characteristics of Ag2Se Nanoparticle Thin Films by Embedding Silicon Nanowires

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3072
Author(s):  
Seunggen Yang ◽  
Kyoungah Cho ◽  
Sangsig Kim
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Thermoelectric Material ◽  
Silicon Nanowires ◽  
High Performance ◽  
Conductivity Measurement ◽  
Thermoelectric Generators ◽  
Seebeck Coefficients ◽  
Thermal Conductivities

A solution-processable Ag2Se nanoparticle thin film (NPTF) is a prospective thermoelectric material for plastic-based thermoelectric generators, but its low electrical conductivity hinders the fabrication of high performance plastic-based thermoelectric generators. In this study, we design Ag2Se NPTFs embedded with silicon nanowires (SiNWs) to improve their thermoelectric characteristics. The Seebeck coefficients are −233 and −240 µV/K, respectively, for a Ag2Se NPTF alone and a Ag2Se NPTF embedded with SiNWs. For the Ag2Se NPTF embedded with SiNWs, the electrical conductivity is improved from 0.15 to 18.5 S/m with the embedment of SiNWs. The thermal conductivities are determined by a lateral thermal conductivity measurement for nanomaterials and the thermal conductivities are 0.62 and 0.84 W/(m·K) for a Ag2Se NPTF alone and a Ag2Se NPTF embedded with SiNWs, respectively. Due to the significant increase in the electrical conductivity and the insignificant increase in its thermal conductivity, the output power of the Ag2Se NPTF embedded with SiNWs is 120 times greater than that of the Ag2Se NPTF alone. Our results demonstrate that the Ag2Se NPTF embedded with SiNWs is a prospective thermoelectric material for high performance plastic-based thermoelectric generators.

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