Theoretical studies on lattice-oriented growth of single-walled carbon nanotubes on sapphire

In this work, a theoretical study is performed to quantitatively understand the van der Waals interactions between single-walled carbon nanotubes (SWNTs) and sapphire substrates. The energetically preferred alignment directions of SWNTs on A-, R- and M-planes and the random alignment on the C-plane predicted by this study are all in good agreement with experiments. It is also shown that smaller SWNTs have better alignment than larger SWNTs due to their stronger interaction with sapphire substrate. The strong vdW interactions along preferred alignment directions can be intuitively explained by the nanoscale ‘grooves’ formed by atomic lattice structures on the surface of sapphire. This study provides important insights to the controlled growth of nanotubes and potentially other nanomaterials.

Z Li et al. Theoretical studies on lattice-oriented growth of single-walled carbon nanotubes on sapphire. Nanotechnology, 28, 385601 (2017).