中国物理B ›› 2013, Vol. 22 ›› Issue (11): 117101-117101.doi: 10.1088/1674-1056/22/11/117101

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

A comparison study on the electronic structures, lattice dynamics and thermoelectric properties of bulk silicon and silicon nanotubes

路朋献, 屈凌波, 程巧换   

  1. College of Materials Science and Engineering, Henan University of Technology, Zhengzhou 450001, China College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China
  • 收稿日期:2013-04-12 修回日期:2013-05-30 出版日期:2013-09-28 发布日期:2013-09-28
  • 基金资助:
    Project supported by the Science Foundation of Henan University of Technology, China (Grant Nos. 2011BS056 and 11JCYJ12) and the Post-Doctor Science Research Fund of China (Grant No. 110832).

A comparison study on the electronic structures, lattice dynamics and thermoelectric properties of bulk silicon and silicon nanotubes

Lu Peng-Xian (路朋献), Qu Ling-Bo (屈凌波), Cheng Qiao-Huan (程巧换)   

  1. College of Materials Science and Engineering, Henan University of Technology, Zhengzhou 450001, China College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, China
  • Received:2013-04-12 Revised:2013-05-30 Online:2013-09-28 Published:2013-09-28
  • Contact: Lu Peng-Xian E-mail:pengxian_lu@haut.edu.cn
  • Supported by:
    Project supported by the Science Foundation of Henan University of Technology, China (Grant Nos. 2011BS056 and 11JCYJ12) and the Post-Doctor Science Research Fund of China (Grant No. 110832).

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摘要： In order to investigate the mechanism of the electron and phonon transport in a silicon nanotube (SiNT), the electronic structures, the lattice dynamics, and the thermoelectric properties of bulk silicon (bulk Si) and a SiNT have been calculated in this work using density functional theory and Boltzmann transport theory. Our results suggest that the thermal conductivity of a SiNT is reduced by a factor of 1, while its electrical conductivity is improved significantly, although the Seebeck coefficient is increased slightly as compared to those of the bulk Si. As a consequence, the figure of merit (ZT) of a SiNT at 1200 K is enhanced by 12 times from 0.08 for bulk Si to 1.10. The large enhancement in electrical conductivity originates from the largely increased density of states at the Fermi energy level and the obviously narrowed band gap. The significant reduction in thermal conductivity is ascribed to the remarkably suppressed phonon thermal conductivity caused by a weakened covalent bonding, a decreased phonon density of states, a reduced phonon vibration frequency, as well as a shortened mean free path of phonons. The other factors influencing the thermoelectric properties have also been studied from the perspective of electronic structures and lattice dynamics.

关键词: electronic structure, lattice dynamics, thermoelectric properties, silicon nanotube

Abstract: In order to investigate the mechanism of the electron and phonon transport in a silicon nanotube (SiNT), the electronic structures, the lattice dynamics, and the thermoelectric properties of bulk silicon (bulk Si) and a SiNT have been calculated in this work using density functional theory and Boltzmann transport theory. Our results suggest that the thermal conductivity of a SiNT is reduced by a factor of 1, while its electrical conductivity is improved significantly, although the Seebeck coefficient is increased slightly as compared to those of the bulk Si. As a consequence, the figure of merit (ZT) of a SiNT at 1200 K is enhanced by 12 times from 0.08 for bulk Si to 1.10. The large enhancement in electrical conductivity originates from the largely increased density of states at the Fermi energy level and the obviously narrowed band gap. The significant reduction in thermal conductivity is ascribed to the remarkably suppressed phonon thermal conductivity caused by a weakened covalent bonding, a decreased phonon density of states, a reduced phonon vibration frequency, as well as a shortened mean free path of phonons. The other factors influencing the thermoelectric properties have also been studied from the perspective of electronic structures and lattice dynamics.

Key words: electronic structure, lattice dynamics, thermoelectric properties, silicon nanotube

中图分类号:  (Density functional theory, local density approximation, gradient and other corrections)

  • 71.15.Mb
72.15.Jf (Thermoelectric and thermomagnetic effects) 63.20.dk (First-principles theory)