研究了定向生长的多壁碳纳米管2～18GHz的复介电常数与复磁导率谱.定向生长的碳纳米管的介电常数要小于采用普通化学气相沉积法制备的碳纳米管,而磁导率大于采用普通化学气相沉积法制备的碳纳米管.透射电镜观察发现定向生长的碳纳米管中腔内规则分布着纳米Fe颗粒,同时也有部分Fe颗粒被碳层片所包覆,沉积在碳纳米管的外表面上. Fe颗粒的存在可以解释定向生长的碳纳米管所具有的较高的磁导率.在定向生长的碳纳米管制备过程中,通过调节催化剂进给数量和速度可以调节Fe颗粒在碳纳米管中的分布,这为碳纳米管的电磁性能的调控提供了一种新的途径.
2～18GHz complex permittivity and complex permeability spectra of directionally grown
carbon nanotubes (CNTs) were studied. The permittivity of directionally grown CNTs is lower than that of CNTs prepared by common chemical vapor deposition (CVD)
method, but permittivity is evidently higher. TEM micrographs show that Fe nano-particles regularly
distribute in the center cavity of directionally grown CNTs. There are also Fe particles covered by carbon layers deposited on the outer surface
of directionally grown CNTs. The existence of Fe particles may explain the higher permeability of directionally grown CNTs. During the preparation of
directionally grown CNTs, the amount and velocity of catalyst feed-in can adjust the distribution of Fe particles in the sample of CNTs, thus providing a new route to modulate the electrical and magnetic properties
of CNTs.
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