Tu Fan, Drost Martin, Szenti Imre, Kiss Janos, Kónya Zoltan, Marbach Hubertus
Lehrstuhl für Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
Department of Applied and Environmental Chemistry, University of Szeged, Szeged, Hungary.
Beilstein J Nanotechnol. 2017 Dec 5;8:2592-2605. doi: 10.3762/bjnano.8.260. eCollection 2017.
We report on the fabrication of carbon nanotubes (CNTs) at predefined positions and controlled morphology, for example, as individual nanotubes or as CNT forests. Electron beam induced deposition (EBID) with subsequent autocatalytic growth (AG) was applied to lithographically produce catalytically active seeds for the localized growth of CNTs via chemical vapor deposition (CVD). With the precursor Fe(CO) we were able to fabricate clean iron deposits via EBID and AG. After the proof-of-principle that these Fe deposits indeed act as seeds for the growth of CNTs, the influence of significant EBID/AG parameters on the deposit shape and finally the yield and morphology of the grown CNTs was investigated in detail. Based on these results, the parameters could be optimized such that EBID point matrixes (6 × 6) were fabricated on a silica surface whereby at each predefined site only one CNT was produced. Furthermore, the localized fabrication of CNT forests was targeted and successfully achieved on an AlO layer on a silicon sample. A peculiar lift-up of the Fe seed structures as "flakes" was observed and the mechanism was discussed. Finally, a proof-of-principle was presented showing that EBID deposits from the precursor Co(CO)NO are also very effective catalysts for the CNT growth. Even though the metal content (Co) of the latter is reduced in comparison to the Fe deposits, effective CNT growth was observed for the Co-containing deposits at lower CVD temperatures than for the corresponding Fe deposits.
我们报道了在预定位置制备具有可控形态的碳纳米管（CNT），例如制备单个纳米管或碳纳米管森林。采用电子束诱导沉积（EBID）并随后进行自催化生长（AG），通过光刻法制备催化活性种子，用于通过化学气相沉积（CVD）实现碳纳米管的局部生长。使用前驱体Fe(CO)，我们能够通过EBID和AG制备纯净的铁沉积物。在证明这些铁沉积物确实可作为碳纳米管生长的种子后，详细研究了重要的EBID/AG参数对沉积物形状以及最终生长的碳纳米管的产率和形态的影响。基于这些结果，可以优化参数，从而在二氧化硅表面制备EBID点矩阵（6×6），使得在每个预定位置仅生成一根碳纳米管。此外，目标是在硅样品上的AlO层上实现碳纳米管森林的局部制备，并成功达成。观察到铁种子结构会以“薄片”形式出现特殊的抬起现象，并对其机理进行了讨论。最后，给出了原理验证，表明来自前驱体Co(CO)NO的EBID沉积物也是碳纳米管生长的非常有效的催化剂。尽管与铁沉积物相比，后者的金属含量（Co）有所降低，但在比相应铁沉积物更低的CVD温度下，观察到含钴沉积物能实现有效的碳纳米管生长。
