Effects of Process Parameters and Substrate Structures on Growth of Single-Walled Carbon Nanotubes by Catalytic Decomposition of Ethanol

Abstract

Single-walled carbon nanotubes (SWNTs) were prepared by ethanol chemical vapor deposition (CVD), using Co and Mo as metal catalysts deposited on Si/SiO2 substrates with and without an Al underlayer. The effects of Mo addition, catalyst particle size and the Al underlayer were discussed on the basis of the results of scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman measurement. In substrates with Si/SiO2/Co/Mo structures, a Co layer with a thickness of 1 nm produced smaller catalyst particles and SWNTs with a thinner diameter and at a higher yield than a Co layer with a thickness of 2 nm. The addition of Mo to Co films in substrates was shown to have the effect of suppressing Co aggregation and keeping catalyst particles small, even with high-temperature CVD growth. It was also found that the introduction of an Al underlayer promoted SWNT growth because of the formation of Al2O3 clusters after heat treatment.

Carbon Nanotubes and Their Growth Methods

“…The general CNTs grown by CVD also belong to open tip growth. However the inner and outer layers of tube are simultaneously sealed & CNTs growth is stopped according to Zhao Y. et al (2006).…”

The growth of carbon nanotube with chemical vapor deposition under different process parameters

“…Increase of temperature to 500 ℃, CNTs and even CNT array are observed. Previous studies showed that metallic Al does not promote CNT growth, and the enhancement in CNT yield was obtained when Al 2 O 3 was formed [16] . During CNT growth, the Al layer melts and forms droplets that absorb oxygen from the SiO 2 layer and oxidize quickly to form thermally stable Al 2 O 3 clusters.…”

Growth of Pd‐Filled Carbon Nanotubes on the Tip of Scanning Probe Microscopy

“…A 10 nm-thick Al film was deposited as a buffer layer on a Si wafer or cantilever. This layer is known to prevent the formation of silicide as well as to support catalyst as nanoparticle [14,15]. Then Pd of 5-40 nm was deposited as catalyst by sputtering.…”