Field enhancement factors of random arrays of carbon nanotubes

The field enhancement factors of flat arrays of aligned, closed-end nanotubes have been determined by accurate computational modelling. Square and random arrays have been considered. The dependence of the enhancement factor on the radius, length and density of the nanotubes has been found for square arrays and the results have been parametrized by a simple empirical function. The density fluctuations of random arrays have been simulated to determine the distribution of enhancement factors. A simple procedure is given for estimating the number of ‘high-emitting’ nanotubes that have enhancement factors much higher than the mean value for the array.