High-Density, Large-Area Single-Walled Carbon Nanotube Networks on Nanoscale Patterned Substrates

Abstract

High-density single-walled carbon nanotubes forming self-directed networks on nanoscale patterned substrates are produced by chemical vapor deposition. The roles of catalyst particles for the growth of single-walled carbon nanotubes are investigated. Transition-metal particles of 3−7 nm size, obtained by depositing thin catalyst films (0.5−1 nm), remain as active catalysts for the growth of high-density single-walled carbon nanotubes on select catalyst supports (SiO2). Highly organized single-walled carbon nanotube architectures with controlled density can be fabricated following the predefined submicrometer-sized substrate patterns, suggesting the possibility of building nanotube-based molecular-scale electronic devices.

Template-directed carbon nanotube network using self-organized Si nanocrystals

“…Nanotubes appear, in fact, to prefer to grow on the oxide. 18 Yet we observe a strong preference for nanotubes to exist between the tops of the Si islands when the island spacing is small. We suggest that the topography of the nanocrystals on the substrate determines the suspended-nanotube network.…”

“…8,18 When the catalyst is distributed evenly over the sample, nanotubes grow both on top of the pillars and on the bottom areas between the pillars. 11 In our experiment, we deposit catalyst over the entire surface and it remains distributed evenly across the substrate, as we observe with SEM at higher magnification, both on top of the Si nanocrystals and on the oxide between the nanocrystals.…”

Direct Synthesis of Single-Walled Carbon Nanotubes on Silicon and Quartz-Based Systems

“…At any temperature, the produced SWNTs retain their high quality judging from its high G/D ratio of about 30. Most notably, with our method, SWNTs were synthesized on the Si surface even at 650°C 31) : This is by far the lowest temperature among the previous reports where 800°C 25,27) or 900°C (or higher) [13][14][15][22][23][24] was employed for SWNT synthesis. This technique is also effective for a quartz substrate and the spectrum (Fig.…”

“…however, in some cases, catalytic metals were mounted on substrates using dry processes such as sputtering or deposition [22][23][24][25][26][27] . Although selective synthesis of SWNTs on a flat Si surface was reported recently 27) , these methods are prone to forming relatively large (i.e.…”

“…Although selective synthesis of SWNTs on a flat Si surface was reported recently 27) , these methods are prone to forming relatively large (i.e. more than 10 nm) agglomerates of catalyst metals and to producing multi-walled carbon nanotubes (MWNTs).…”