Electron emission properties of carbon nanotubes

We report on the ®eld emission properties of carbon nanotubes, focusing on current density versus electric ®eld (J±F) characteristics and the spacing between the emitter and collector. We grew carbon nanotubes on SUS304, nickel, Inconel-600, and Invar-42 substrates using plasma-enhanced chemical vapor deposition, using methane gas as the carbon source and hydrogen gas as the catalyst and dilution gas. We found that nanotubes grew fastest on Invar-42. Nanotubes were distributed from 50 to 100 nm in diameter and from 1 to 30 mm long. Onset ®eld of the ®eld emission was 0.7 V/mm and the current density was 1 mA/cm2 at an electric ®eld of 3.0 V/mm. A Fowler±Nordheim plot was made. Field enhancement factor b and emission area a were calculated and compared between substrates. Using nickel on quartz glass, carbon nanotubes were selectively fabricated on metal lines on quartz glass. # 2001 Elsevier Science B.V. All rights reserved.