Field emission current saturation of aligned carbon nanotube Effect of density and aspect ratio

The investigation of field emission (FE) properties of carbon nanotube film reveals a strong dependency on the density and its aspect ratio. Nonlinearity in the Fowler-Nordheim (F-N) plot has been explained in terms of change in work function of carbon due to heating during FE. A characteristic knee in the F-N plot, separates the linear region from the nonlinear region. I-knee value turns out to be a basic parameter to define the FE process. It has been shown that an optimum density and length of the nanotubes have high efficiency of field emission. An explanation has been given for the phenomena responsible for efficient field emission in short nanotubes