scholarly journals A universal gauge for thermal conductivity of silicon nanowires with different cross sectional geometries

2011 ◽  
Vol 135 (20) ◽  
pp. 204705 ◽  
Author(s):  
Jie Chen ◽  
Gang Zhang ◽  
Baowen Li
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nanowires ◽  
Cross Sectional

The Effect of Cross-sectional Geometry on ZT Enhancement in Rough Silicon Nanostructures

2010 ◽  
Vol 1267 ◽  
Author(s):  
Jyothi Swaroop Sadhu ◽  
Marc G Ghossoub ◽  
Sanjiv Sinha
Keyword(s):  
Thermal Conductivity ◽  
Boundary Condition ◽  
Cross Section ◽  
Silicon Nanowires ◽  
Silicon Nanostructures ◽  
Dramatic Reduction ◽  
Cross Sectional ◽  
The Wire ◽  
Phonon Localization ◽  
The Impact

AbstractThe dramatic reduction in the thermal conductivity of rough silicon nanowires is due to phonon localization in the wire resulting from multiple scattering of phonons from the rough walls. We report the dependence of thermal conductivity of the nanowires as a function of the surface roughness and the diameter of the wire by modeling the nanowire as a waveguide. In addition, we estimate the impact of boundary condition, dimensionality and cross section of rough wire on the thermal conductivity. This theoretical model gives insights for tailoring thermal conductivity and enhancing the ZT of silicon to 1 for its use in thermoelectrics

Effect of cross-sectional geometry on thermal conductivity of Si1−xGex nanowires

2016 ◽  
Vol 30 (18) ◽  
pp. 1650108
Author(s):  
Peixin Qu
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nanowires ◽  
Silicon Germanium ◽  
High Frequency ◽  
Low Frequency ◽  
Volume Ratio ◽  
Boltzmann Transport ◽  
Cross Sectional ◽  
Atom Concentration ◽  
Pure Silicon

By incorporating the direction-dependent phonon-boundary scattering from the surface of the nanowires with different cross-sectional shapes into the linearized phonon Boltzmann transport equation, we theoretically investigate the effect of cross-sectional geometry on the thermal conductivity of [Formula: see text] nanowires. It is demonstrated that the surface-to-volume ratio (SVR) is a universal gauge for both pure silicon nanowires (SiNWs) and silicon–germanium nanowires (SiGe NWs), and the thermal conductivity of nanowires decreases monotonically with the increase of SVR. We also find that the thermal conductivity of high-frequency phonons in nanowires is more strongly SVR dependent than that of low-frequency phonons, and the thermal conductivity of high-frequency phonons is severely suppressed by alloy scattering, therefore the SVR dependence on thermal conductivity of [Formula: see text] NWs decreases with the increase of Ge atom concentration [Formula: see text] [Formula: see text]. These findings are useful for understanding and tuning the thermal conductivity of nanowires by geometry.

Infrared Diagnostics of Free Charge Carriers in Silicon Nanowires

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940030 ◽  
Author(s):  
A. I. Efimova ◽  
E. A. Lipkova ◽  
K. A. Gonchar ◽  
A. A. Eliseev ◽  
V. Yu. Timoshenko
Keyword(s):  
Silicon Nanowires ◽  
Crystalline Silicon ◽  
Free Charge Carrier ◽  
Charge Carrier Concentration ◽  
Attenuated Total Reflection ◽  
Free Charge ◽  
Cross Sectional ◽  
Text Type ◽  
Cross Sectional Size ◽  
Potential Applications

Free charge carrier concentration in arrays of silicon nanowires (SiNWs) with cross-sectional size of the order of 100[Formula: see text]nm was quantitatively studied by means of the infrared spectroscopy in an attenuated total reflection mode. SiNWs were formed on lightly-doped [Formula: see text]-type crystalline silicon substrates by metal-assisted chemical etching followed by additional doping through thermoactivated diffusion of boron at 900–1000∘C. The latter process was found to increase the concentration of free holes in SiNWs up to [Formula: see text][Formula: see text]cm[Formula: see text]. Potential applications of highly doped SiNWs in thermoelectric energy converters and infrared plasmonic devices are discussed.

Thermal conductivity of silicon nanowires embedded on thermoelectric platforms

2016 ◽  
Vol 27 (10) ◽  
pp. 105007 ◽  
Author(s):  
JinYong Choi ◽  
Kyoungah Cho ◽  
Dae Sung Yoon ◽  
Sangsig Kim
Keyword(s):  
Thermal Conductivity ◽  
Silicon Nanowires

Thermal Conductivity in Thin Silicon Nanowires with Rough Surfaces by Molecular Dynamics Simulations

2010 ◽  
Author(s):  
Xueming Yang ◽  
Albert C. To ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
Vai Pan Iu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Silicon Nanowires ◽  
Rough Surfaces ◽  
Thin Silicon ◽  
Dynamics Simulations

scholarly journals Rigid Polyurethane Foams Modified with Biochar

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5616
Author(s):  
Katarzyna Uram ◽  
Maria Kurańska ◽  
Jacek Andrzejewski ◽  
Aleksander Prociak
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Thermal Insulation ◽  
Foam Cells ◽  
Polyurethane Foams ◽  
Cross Sectional ◽  
Rigid Polyurethane Foams ◽  
Insulation Materials

This paper presents results of research on the preparation of biochar-modified rigid polyurethane foams that could be successfully used as thermal insulation materials. The biochar was introduced into polyurethane systems in an amount of up to 20 wt.%. As a result, foam cells became elongated in the direction of foam growth and their cross-sectional areas decreased. The filler-containing systems exhibited a reduction in their apparent densities of up to 20% compared to the unfilled system while maintaining a thermal conductivity of 25 mW/m·K. Biochar in rigid polyurethane foams improved their dimensional and thermal stability.

Sign in / Sign up

Export Citation Format

Share Document