中国物理B ›› 2013, Vol. 22 ›› Issue (3): 37701-037701.doi: 10.1088/1674-1056/22/3/037701

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

Carbon materials with quasi-graphene layers: the dielectric, percolation properties and the electronic transport mechanism

卢明明a, 袁杰a b, 温博a, 刘甲a, 曹文强b, 曹茂盛a   

  1. a School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081, China;
    b School of Information Engineering, Minzu University of China, Beijing 100081, China
  • 收稿日期:2012-07-12 修回日期:2012-09-05 出版日期:2013-02-01 发布日期:2013-02-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 50972014, 51072024, and 51132002).

Carbon materials with quasi-graphene layers: the dielectric, percolation properties and the electronic transport mechanism

Lu Ming-Ming (卢明明)a, Yuan Jie (袁杰)a b, Wen Bo (温博)a, Liu Jia (刘甲)a, Cao Wen-Qiang (曹文强)b, Cao Mao-Sheng (曹茂盛)a   

  1. a School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081, China;
    b School of Information Engineering, Minzu University of China, Beijing 100081, China
  • Received:2012-07-12 Revised:2012-09-05 Online:2013-02-01 Published:2013-02-01
  • Contact: Yuan Jie E-mail:yuanjie4000@163.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 50972014, 51072024, and 51132002).

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摘要： We investigate the dielectric properties of multi-walled carbon nanotubes (MWCNTs) and graphite filling in SiO2 with the filling concentration of 2-20 wt.% in the frequency range of 102-107 Hz. MWCNTs and graphite have general electrical properties and percolation phenomena owing to their quasi-structure made up of graphene layers. Both permittivity ε and conductivity σ exhibit jumps around the percolation threshold. Variations of dielectric properties of the composites are in agreement with the percolation theory. All the percolation phenomena are determined by hopping and migrating electrons, which are attributed to the special electronic transport mechanism of the fillers in the composites. However, the twin-percolation phenomenon exists when the concentration of MWCNTs is between 5-10 wt.% and 15-20 wt.% in the MWCNTs/SiO2 composites, while in the graphite/SiO2 composites, there is only one percolation phenomenon in the graphite concentration of 10-15 wt.%. The unique twin-percolation phenomenon of MWCNTs/SiO2 is described and attributed to the electronic transfer mechanism, especially the network effect of MWCNTs in the composites. The formation of network plays an essential role in determining the second percolation threshold of MWCNTs/SiO2.

关键词: multi-walled carbon nanotube, quasi-graphene layer, dielectric properties, percolation

Abstract: We investigate the dielectric properties of multi-walled carbon nanotubes (MWCNTs) and graphite filling in SiO2 with the filling concentration of 2–20 wt.% in the frequency range of 102–107 Hz. MWCNTs and graphite have general electrical properties and percolation phenomena owing to their quasi-structure made up of graphene layers. Both permittivity ε and conductivity σ exhibit jumps around the percolation threshold. Variations of dielectric properties of the composites are in agreement with the percolation theory. All the percolation phenomena are determined by hopping and migrating electrons, which are attributed to the special electronic transport mechanism of the fillers in the composites. However, the twin-percolation phenomenon exists when the concentration of MWCNTs is between 5–10 wt.% and 15–20 wt.% in the MWCNTs/SiO2 composites, while in the graphite/SiO2 composites, there is only one percolation phenomenon in the graphite concentration of 10–15 wt.%. The unique twin-percolation phenomenon of MWCNTs/SiO2 is described and attributed to the electronic transfer mechanism, especially the network effect of MWCNTs in the composites. The formation of network plays an essential role in determining the second percolation threshold of MWCNTs/SiO2.

Key words: multi-walled carbon nanotube, quasi-graphene layer, dielectric properties, percolation

中图分类号:  (Permittivity (dielectric function))

  • 77.22.Ch
73.23.-b (Electronic transport in mesoscopic systems) 72.80.Tm (Composite materials) 72.20.Ee (Mobility edges; hopping transport)