High Thermoelectric Performance of Ge/Si Core−Shell Nanowires: First-Principles Prediction

2010 ◽  
Vol 114 (19) ◽  
pp. 9096-9100 ◽  
Author(s):  
Xin Chen ◽  
Yanchao Wang ◽  
Yanming Ma
Keyword(s):  
First Principles ◽  
Thermoelectric Performance ◽  
Core Shell ◽  
Shell Nanowires

Regulating the electronic and optical properties of GaN/InN core/shell nanowires: A first-principles study

2020 ◽  
Vol 34 (25) ◽  
pp. 2050214 ◽  
Author(s):  
Chang Liu ◽  
Enling Li ◽  
Tuo Peng ◽  
Kaifei Bai ◽  
Yanpeng Zheng ◽  
...  
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Core Shell ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Gan Nanowires ◽  
The Core ◽  
Light Region ◽  
Calculation Results ◽  
Shell Nanowires

In this paper, electronic and optical properties of GaN/InN core/shell nanowires (CSNWs) have been theoretically investigated through the first principles calculations. The binding energy of In and N atoms on surface of six crystal planes along the [Formula: see text]-axis of GaN nanowires are all negative, which indicate that In and N atoms can be effectively deposited on the surface of GaN nanowires and preparing GaN/InN CSNWs is feasible theoretically. Calculation results of electronic properties indicate that the core/shell ratio and diameter of GaN/InN CSNWs have significant effect on the band structure, bandgap can be effectively adjusted when keeping the number of GaN layers unchanged and changing the number of InN layers. Moreover, with the increase in the number of InN layers, the absorption spectrum of GaN/InN CSNW has significant redshift and few weak absorption peaks appear in the visible light region.

Thermoelectric Modeling of Si-Si1−xGex Ordered Nanowire Composites

2005 ◽  
Vol 886 ◽  
Author(s):  
Ming Y. Tang ◽  
Mildred S. Dresselhaus ◽  
Ronggui Yang ◽  
Gang Chen
Keyword(s):  
Thermoelectric Materials ◽  
Model Systems ◽  
Thermoelectric Performance ◽  
Core Shell ◽  
Host Matrix ◽  
Electronic Density ◽  
Quantum Confinement Effects ◽  
Interface Scattering ◽  
Low Dimensional ◽  
Shell Nanowires

ABSTRACTThermoelectrics have always been attractive for power generation and cooling because of power reliability and environmentally friendly issues. However, this concept remains non-competitive due to the limitation in the efficiency of available thermoelectric materials and device designs [1]. In the 1990s, Hicks and Dresselhaus predicted the possibility of a dramatic enhancement in thermoelectric performance based on the special behavior of low dimensional materials [2, 3]. This enhancement is in part due to the increase in quantum confinement effects, the increase in electronic density of states at specified energies, and the increase in the phonon interface scattering for low dimensional structures.Nanowires and core-shell nanowires can be considered to be model systems to illustrate representative behavior in low dimensional thermoelectric materials. It is expected that a system made out of nanowires or core-shell nanowires would have a higher thermoelectric performance than its bulk counterpart due to an increase in the number of interfaces. The interfaces that are introduced must be such that phonons are scattered more strongly than are electrons. Theoretical studies have been carried out to better understand the transport properties of Si-Si1−xGex ordered nanowire composites. The composite is modeled as having Si wires embedded in a Si1−xGex host matrix. Thus, core-shell Si/Si1−xGex nanowires can be considered as a building block of the composite. The effect of the wire diameter and the shell alloy composition on ZT is presented.

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