Field emission spectroscopy of nanographite films

Nanocarbon films with high aspect ratio graphite crystallites were fabricated by plasma-enhanced chemical vapor deposition. In order to reveal the origin of their extraordinary field emission properties, integral current-voltage curves and electron spectra from two nanographite cathodes with different morphology were measured in triode configuration. An average current density of about 1 mA/cm
²
was reproducibly obtained at an applied field of 1.2-1.8 V/μm due to high field enhancement. Most remarkably, above a threshold field the electron spectra of both samples revealed two peaks with different field-dependent shift to lower energy. The role of sp
³
surface states for these results will be discussed at the conference.