The environmental stability of field emission from single-walled carbon nanotubes

We demonstrate long-term field emission stability from single-walled carbon nanotubes. Unballasted nanotubes operate without degradation for over 350 h at 10(-9) Torr. Nanotubes are shown to be significantly less sensitive to operating environments than metallic emitters. In 10(-7) Torr of H2O, we demonstrate 100 h of continuous bias field emission with no current degradation. Protrusion growth and current runaway, typical problems for unballasted metal emitters, are not observed with nanotubes. Single-walled nanotubes do show susceptibility to damage by oxidation. We suggest that the exceptional environmental stability of carbon nanotubes is due to a combination of geometry, strong carbon bonding, and the lack of protrusion growth. (C) 1999 American Institute of Physics. [S0003-6951(99)03245-3].