Carbon nanotube growth from Langmuir–Blodgett deposited Fe3O4 nanocrystals
Carbon nanotube growth from Langmuir–Blodgett deposited Fe3O4 nanocrystals
复制标题
从 Langmuir-Blodgett 沉积的 Fe3O4 纳米晶体中生长碳纳米管
DOI：
10.1088/0957-4484/23/40/405604
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发表时间：
2012
期刊：
影响因子：
3.5
通讯作者：
P. Vereecken
中科院分区：
文献类型：
--
作者：
M. H. van der Veen;M. Cirillo;K. Lambert;Stijn Flamée;M. Bodnarchuk;W. Heiss;S. De Gendt;Z. Hens;P. Vereecken
我们研究胶体Fe3O4纳米晶体作为碳纳米管（CNT）生长的催化剂系统，允许从催化剂成型和活化步骤解耦CNT生长步骤。该系统由6.4 nm的Fe3O4纳米晶体使用基于溶液的热分解反应合成，随后，转移为六方有序的LB单层TiN基板上。我们首次展示了从LB沉积的纳米晶体上的金属底层对齐CNT生长。六方有序的单层催化剂颗粒显示出有前途的稳定性高达CNT生长温度。进行原位TEM加热实验以发现颗粒变形的开始，并显示纳米颗粒在高达600 °C下的稳定性。高温下的颗粒聚结也通过增加CNT直径（从580 °C下的9.5 nm增加到630 °C下的16 nm）来证明。通过选择在低于起始颗粒聚结温度的温度下工作，在不同的催化剂活化和生长条件下获得等效的CNT直径。在金属底层上的催化剂的高稳定性使我们能够独立于催化剂成形步骤来研究CNT生长动力学。这项工作开辟了一条路线，结合生长的CNT生长的TiN可以用作底部接触的电气评价的研究。
We investigate colloidal Fe3O4 nanocrystals as a catalyst system for carbon nanotube (CNT) growth that allows for decoupling the CNT growth step from the catalyst shaping and activation step. The system consists of 6.4 nm Fe3O4 nanocrystals synthesized using a solution-based thermal decomposition reaction and, subsequently, transferred as hexagonally ordered Langmuir–Blodgett (LB) monolayers on TiN substrates. We demonstrate for the first time aligned CNT growth from LB deposited nanocrystals on a metallic underlayer. The hexagonally ordered monolayers of catalyst particles show promising stability up to the CNT growth temperature. In situ TEM heating experiments were performed to find this onset of particle deformation and showed stability of the nanoparticles up to 600 °C. The particle coalescence at high temperatures was also evidenced by the increasing CNT diameter, from 9.5 nm at 580 °C to 16 nm at 630 °C. By choosing to work at temperatures below the onset particle coalescence temperature, equivalent CNT diameters were obtained under different catalyst activation and growth conditions. The high stability of the catalyst on the metallic underlayer enables us to study CNT growth kinetics independently of the catalyst shaping step. This work opens a route towards combining growth studies with an electrical evaluation of the CNT growth as the TiN can be used as the bottom contact.