Scanning electron microscopy of field-emitting individual single-walled carbon nanotubes

Abstract

The use of scanning electron microscope (SEM) to view the emission from individual single-walled carbon nanotubes (SWCNT) by applying an external field close to the onset of field-emission and then scanning the tube with the electron beam of the SEM was demonstrated. The SWCNT were grown by using chemical vapor depositon (CVD) for 5 min at 850°C with methane and ethylene as precursors and hydrogen as a background gas. It was observed that at the onset of emission, the SEM image did indeed, as speculated, exhibit a few bright spots corresponding to the positions of the CNT tips. Black radial patterns emanating from the emission point toward the extractor electrode were also observed.