Bulmer John S, Martens Jon, Kurzepa Lukasz, Gizewski Tomasz, Egilmez M, Blamire M G, Yahya Noorhana, Koziol Krzysztof K K
Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK.
Anritsu Corporation, 490 Jarvis Dr Morgan Hill, CA 95037.
Sci Rep. 2014 Jan 21;4:3762. doi: 10.1038/srep03762.
Recent progress with tailored growth and post-process sorting enables carbon nanotube (CNT) assemblies with predominantly metallic or semi-conducting concentrations. Cryogenic and microwave measurements performed here show transport dimensionality and overall order increasing with increasing metallic concentration, even in atmospheric doping conditions. By 120 GHz, the conductivity of predominantly semi-conducting assemblies grew to 400% its DC value at an increasing growth rate, while other concentrations a growth rate that tapered off. A generalized Drude model fits to the different frequency dependent behaviors and yields useful quality control parameters such as plasma frequency, mean free path, and degree of localization. As one of the first demonstrations of waveguides fabricated from this material, sorted CNTs from both as-made and post-process sources were inserted into sections of practical micro-strip. With both sources, sorted CNT micro-strip increasingly outperformed the unsorted with increasing frequency-- illustrating that sorted CNT assemblies will be important for high frequency applications.
定制生长和后处理分选方面的最新进展使得能够制备出具有主要为金属或半导体浓度的碳纳米管（CNT）组件。在此进行的低温和微波测量表明，即使在大气掺杂条件下，随着金属浓度的增加，传输维度和整体有序度也会增加。到120吉赫兹时，主要为半导体组件的电导率以不断增加的增长率增长至其直流值的400%，而其他浓度的增长率则逐渐下降。一个广义德鲁德模型适用于不同的频率依赖行为，并得出诸如等离子体频率、平均自由程和局域化程度等有用的质量控制参数。作为用这种材料制造波导的首批示范之一，将来自原始和后处理源的分选碳纳米管插入实际微带的部分。对于这两种源，随着频率增加，分选碳纳米管微带的性能越来越优于未分选的——这表明分选碳纳米管组件对于高频应用将很重要。
