Growth of aligned carbon nanotubes on ALD-Al₂O₃coated silicon and quartz substrates

Abstract

The smooth surface of the amorphous Al 2 O 3 film on either silicon or quartz, coated by atomic layer deposition (ALD), was changed to rough surface by annealing in either air or hydrogen at high temperature (745 C) due to the formation of nanosized pinholes and micrometre pimples during the crystallisation of the amorphous Al 2 O 3 . The rough surface makes the growth of long carbon nanotubes (CNTs) by chemical vapour deposition impossible. Nevertheless, we were able to develop new catalyst recipes for successful growth of vertically aligned CNTs on ALD-Al 2 O 3 coated silicon and quartz substrates. The lengths of the CNTs reached 90 mm on silicon substrates and 180 mm on quartz substrates. Furthermore, it is observed that the adhesion of CNTs on silicon substrates is much stronger than that on quartz substrates.

Influence of oxide buffer layers on the growth of carbon nanotube arrays on carbon substrates

“…The resulting thin film should be pinhole-free and conformal to the substrate surface [32]. The organometallic precursors used for deposition of Al 2 O 3 and SiO 2 were trimethylaluminum, and trisdimethylamino-silane, respectively.…”