Comparison of Field Emission in Carbon Nanotubes and Gallium-doped Carbon Nanotubes

Carbon nanotubes and Ga-doped carbon nanotubes were synthesized by pyrolysis and then purified. Thin films of the purified samples were fabricated by a screen-printing method. Field emission properties of these films were studied. It was shown that the turn-on field of carbon nanotubes and Ga-doped carbon nanotubes was 2.22V/μm and 1.0V/μm, and the current densities were 400μA/cm2 and 4000μA/cm2 for carbon nanotubes and Ga-doped carbon nanotubes at applied fields 2.4V/μm. The electron field emission properties of the gallium-doped nanotubes were much better than those of carbon nanotubes. Mechanisms of field emission of gallium-doped nanotubes were explained.