Diameter-controlled growth of aligned single-walled carbon nanotubes on quartz using molecular nanoclusters as catalyst precursors

Fei Peng,Yan Li,Hao Sun,Jinyong Wang,Ruoming Li,Feng Yang,Da Luo,Juan Yang

doi:10.1007/s11434-012-5588-y

Abstract

Molecular nanoclusters containing Fe and Mo atoms have been used as catalyst precursors for the growth of single-walled carbon nanotubes (SWNTs) on stable temperature (ST)-cut quartz substrates by chemical vapor deposition. Attribute to the uniform catalyst nanoparticles and the confinement effect of the crystalline substrates, well-aligned SWNTs with narrow diameter distribution have been synthesized. Atomic force microscopy measurements show that the mean diameter of the nanotubes obtained by thermal decomposition of ethanol at 900°C is 0.76 ± 0.16 nm, which is the smallest among all reported results for aligned SWNTs. The mean diameter of the nanotubes increases with growth temperature. In addition to using identical nanoclusters as the catalyst precursors, the avoidance of annealing treatment of catalyst precursors is also a key point for obtaining SWNTs with controlled diameters. Using these identical nanoclusters as catalyst precursors and carefully tuning the growth parameters make us closer to the ultimate goal of controlling the chirality of SWNTs.

Highlights

Chemical vapor depositionStable temperature (ST)-cut single crystal quartz was used as the substrate for the SWNT growth
Molecular nanoclusters containing Fe and Mo atoms have been used as catalyst precursors for the growth of single-walled carbon nanotubes (SWNTs) on stable temperature (ST)-cut quartz substrates by chemical vapor deposition
For SWNTs grown at higher temperatures (940 and 970°C), the mean diameter increased to 1.29 nm and 1.53 nm respectively and the diameter distribution were broader (Figure 2(c) and (d))

Summary

Chemical vapor deposition

Stable temperature (ST)-cut single crystal quartz was used as the substrate for the SWNT growth. The catalyst precursors were dissolved in the mixed solvent of 80% ethanol and 20% water. After dropping the catalyst precursor solution onto the substrate and drying in ambient atmosphere, the substrate was placed into the quartz tube reactor. The substrate was at first heated to 900 970°C in 200 standard-state cubic centimeters per minute (sccm) of H2, and ethanol was bubbled into the reactor with 100 sccm of. H2 for 15 min to grow SWNTs. it was cooled down to room temperature under Ar flow

Characterization

Results and discussion

Conclusions