Conductivity enhancement in single-walled carbon nanotube bundles doped with K and Br
Conductivity enhancement in single-walled carbon nanotube bundles doped with K and Br
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DOI：
10.1038/40822
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发表时间：
1997-07-17
期刊：
影响因子：
64.8
通讯作者：
Smalley, RE
中科院分区：
文献类型：
--
作者：
Lee, RS;Kim, HJ;Smalley, RE
单壁碳纳米管 (SWNT) 通过金属催化激光烧蚀石墨制备，形成紧密堆积的束或“绳”(1)。这些绳状微晶在 50 K 以上表现出金属行为（参考文献 2），单个管的行为类似于分子线，在低温下表现出量子效应 (3,4)。他们提供了一种 ah-碳主晶格，与石墨 (5) 和固体 C-60（参考文献 6）类比，可能会形成具有有趣电子特性的插层化合物，例如增强的导电性和超导性。多壁纳米管材料掺杂有碱金属 (7) 和 FeCl3（参考文献 8）。在这里，我们报告了通过与溴和钾（分别是典型的电子受体和供体）的气相反应对单壁碳纳米管批量样品进行掺杂。掺杂使 300 K 时的电阻率降低了 30 倍，并扩大了电阻温度系数为正的区域（金属行为的特征）。这些结果表明，掺杂的单壁碳纳米管代表了一个新的合成金属家族。
Single-walled carbon nanotubes (SWNTs), prepared by metal-catalysed laser ablation of graphite, form close-packed bundles or 'ropes'(1). These rope crystallites exhibit metallic behaviour above 50 K (ref. 2), and individual tubes behave as molecular wires, exhibiting quantum effects at low temperatures(3,4). They offer an ah-carbon host lattice that, by analogy with graphite(5) and solid C-60 (ref. 6), might form intercalation compounds with interesting electronic properties, such as enhanced electrical conductivity and superconductivity. Multi-walled nanotube materials have been doped with alkali metals(7) and FeCl3 (ref. 8). Here we report the doping of bulk samples of SWNTs by vapour-phase reactions with bromine and potassium-a prototypical electron acceptor and donor respectively Doping decreases the resistivity at 300 K by up to a factor of 30, and enlarges the region where the temperature coefficient of resistance is positive (the signature of metallic behaviour). These results suggest that doped SWNTs represent a new family of synthetic metals.