Directed assembly of carbon nanotube electronic circuits by selective area chemical vapor deposition on prepatterned catalyst electrode structures

Abstract
Electron-beam lithography was used to pattern Fe thin film electrode structures on silicon dioxide covered Si wafers. The Fe film also serves as a catalyst in subsequent chemical vapor deposition of carbon nanotubes. Chemical vapor deposition was performed in a stainless steel chamber using acetylene at a partial pressure of 100 mTorr and a substrate temperature of 660 °C. Transmission electron microscopy images reveal that the carbon nanotubes grown by this method are multiwalled. The carbon nanotubes selectively grow only on the catalyst film and eventually bridge the intentionally designed micron size electrode gap forming carbon nanotube electronic circuits. The resulting devices were characterized by electronic transport measurements in a temperature range from room temperature down to 2 K.