Direct visualization of electrical transport-induced alloy formation and composition changes in filled multi-wall carbon nanotubes by in situ scanning transmission electron microscopy
Direct visualization of electrical transport-induced alloy formation and composition changes in filled multi-wall carbon nanotubes by in situ scanning transmission electron microscopy
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DOI：
10.1016/j.jallcom.2017.05.316
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发表时间：
2017-10
影响因子：
6.2
通讯作者：
Z. Aslam;J. Lozano;R. Nicholls;A. Koós;F. Dillon;M. Sarahan;P. Nellist;N. Grobert
中科院分区：
文献类型：
--
作者：
Z. Aslam;J. Lozano;R. Nicholls;A. Koós;F. Dillon;M. Sarahan;P. Nellist;N. Grobert
为了评估金属填充碳纳米管的适用性，了解它们在电流存在下的行为至关重要。在这项工作中，我们利用了显着的优势，结合原位实验与扫描透射电子显微镜在环形暗场模式和相关的分析技术，以获得进一步的洞察到铁填充的P，N掺杂的多壁碳纳米管的电输运诱导的转变。通过这些协同分析技术，我们可以真实的时间监测发生在碳纳米管和它们的Fe填充物中的动态效应，作为通过电流和随后的焦耳加热的结果。采用透射电子显微镜、扫描透射电子显微镜和分析技术进行原位实验，可以对中间相的形成、演变和组成进行详细分析。我们发现，发生一个多阶段的过程中，Fe填充反应与氮形成一个中间合金相，然后分解。发现管的内部通道内的高浓度氮气的存在对该过程至关重要。
In order to evaluate the applicability of metal-filled carbon nanotubes, it is crucial to understand their behaviour in the presence of electric currents. In this work we exploit the significant advantages of combining in situ experiments with scanning transmission electron microscopy in annular dark-field mode and related analytical techniques to gain further insights into the electrical transport induced transformations in Fe-filled P,N-doped multi-wall carbon nanotubes. With these synergistic analysis techniques, we could monitor in real time the dynamical effects that take place in the carbon nanotubes and their Fe filling as a consequence of the passing of an electric current and subsequent Joule heating. A detailed analysis of the formation, evolution and composition of intermediate phases has been possible employing in situ experiments with transmission electron microscopy, scanning-transmission electron microscopy and analysis techniques. We show that a multistage process occurs in which the Fe filling reacts with nitrogen to form an intermediate alloy phase, which then decomposes. The presence of high concentrations of nitrogen within the inner channel of the tube is found to be crucial to this process.