Abstract
We investigated the growth behavior and morphology of vertically aligned carbon nanotubes (CNTs) on silicon (Si) substrates by direct current (DC) plasma enhanced chemical vapor deposition (PECVD). We found that plasma etching and precipitation of the Si substrate material significantly modified the morphology and chemistry of the synthesized CNTs, often resulting in the formation of tapered-diameter nanocones containing Si. Either low bias voltage (∼500 V) or deposition of a protective layer (tungsten or titanium film with 10-200 nm thickness) on the Si surface suppressed the unwanted Si etching during growth and enabled us to obtain cylindrical CNTs with minimal Si-related defects. We also demonstrated that a gate electrode, surrounding a CNT in a traditional field emitter structure, could be utilized as a protection layer to allow growth of a CNT with desirable high aspect ratio by preventing the nanocone formation.
| Original language | English |
|---|---|
| Pages (from-to) | 835-840 |
| Number of pages | 6 |
| Journal | Carbon |
| Volume | 43 |
| Issue number | 4 |
| DOIs | |
| State | Published - 2005 |
Bibliographical note
Funding Information:We acknowledge the support of the work by University of California Discovery Fund under Grant No. ele02-10133/Jin, NSF NIRTs under Grant No. DMI-0210559 and DMI-0303790. The authors would like to thank Dr. Alexander Tikhonovsky for assistance in TEM studies and helpful discussions.
Keywords
- A. Carbon nanotubes
- B. Chemical vapor deposition
- C. Scanning electron microscopy, Transmission electron microscopy