Influence of Catalyst Film Thickness Deposited by Atomic Layer Deposition on Growth of Aligned Carbon Nanotubes

doi:10.15541/jim20150594

Abstract

Abstract:

Al₂O₃ buffer layer and Fe₂O₃ catalyst film were deposited on Si wafer successively by atomic layer deposition (ALD). The coated Si wafer was used to grow vertically aligned carbon nanotubes (VACNTs) by water-assisted chemical vapor deposition (WACVD). Results show that catalytically active nanoparticles form in the ALD deposited Fe₂O₃ film after heat-treatment in reduced atmosphere, and the thickness of Fe₂O₃ film is closely related to the size of catalytic nanoparticles and the structure of VACNTs grown. For 1.2 nm-thick Fe₂O₃ film as catalyst layer, the VACNTs have an outer diameter of ~10 nm, wall numbers of ~ 5 and height of ~ 400 μm. Increasing the thickness of Fe₂O₃ film leads to outer diameter and wall number of VACNTs increasing, but the height of which decreasing. It is also observed that VACNTs grows on the side face of Si wafer, which indicates that ALD technique can be useful for VACNTs growth on three-dimensional substrate.

Key words: atomic layer deposition, iron oxide, water-assisted chemical vapor deposition, vertically aligned carbon nanotubes, controlled structure, three-dimensional sample

CLC Number:

TQ174

YANG Chao, LI Ying, YAN Lu, CAO Yun-Zhen. Influence of Catalyst Film Thickness Deposited by Atomic Layer Deposition on Growth of Aligned Carbon Nanotubes[J]. Journal of Inorganic Materials, 2016, 31(7): 681-686.

Figures/Tables 4

Fig. 1 Analysis and characterization of Fe2O3 for catalytic film(a) Growth rate of Fe2O3 versus pulse time; (b) film thickness of Al2O3 and Fe2O3 versus cycles; (c) XPS spectrum of Fe2p from Fe2O3 film

Fig. 2 Surface AFM images of Fe2O3 films with different thicknesses after reduced for 5 min (a-c) and TEM images of CNT grown from Fe2O3 films with different thicknesses (d-f)

Fig. 3 Characterizations of Fe2O3 films with different thicknesses before and after being grown VACNTS (a) Particles diameter distribution of Fe2O3 films with different thicknesses after reduced for 5 min; (b) Outer diameter; (c) Wall numbers distribution; (d) Raman spectra of VACNTs grown on Fe2O3 films with different thicknesses

Fig. 4 Morphotogy and structure of VACNTs (a) Side-view T-SEM image of vertically aligned VACNTs; (b) Section T-SEM image of vertically aligned VACNTs; (c) TEM image of VACNTs; (d) T-SEM image of horizontally aligned VACNTs on the side of Si wafer

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