Fabrication of carbon nanotube field emission cathodes in patterns by a laser transfer method

This study reports a novel approach, based on the method of laser induced pattern transfer, that can deposit patterned carbon nanotube (CNT) field emission cathodes on a variety of substrates at room temperature and in an ambient environment. Tests of emission characteristics of the fabricated cathodes present favourable emission current flux, low threshold electrical field, 1 mA cm^-2 current density at 3.3 V νm^-1 for the 8 νm thick film and good emission focusing. Well-defined CNT patterns with a feature size down to 10 νm were produced using a mask. Compared with CNT film produced by printing based methods, higher density and better adhesion were achieved, without any post-treatment. Control of the film thickness can plainly be accomplished by adjusting the coated CNT film thickness on the support and the number of laser pulses. The fast deposition rate and high degree of feasibility of using the substrate, as well as the fabrication environment, render the proposed approach a potential method for low cost fabrication of precision patterns for CNT.