Field emission properties of carbon nanotubes pastes examined using design of experiment

Field emission properties of screen-printed carbon nanotube (CNT) pastes were investigated by design of experiments (DOE) using three, two-level, input factors. Characterization showed that the multi-walled carbon nanotubes (MWNTs) with a diameter of approximately 5 nm containing 5 wt. % of carbonaceous impurities were almost completely burnt out after heating to 600°C in air, while 96% of the sample remained even up to 800°C in a nitrogen atmosphere. Experimental measurements using a diode structure for eight sample groups revealed an emission current density of 52–87 μA/cm2 in an electric field of 5 V/μA and a field enhancement factor of 12,079–16,922, assuming the work function of MWNTs to be 5 eV, thereby demonstrating superior emission properties with the sample containing a larger amount of MWNTs. A long-term, 110-h reliability test showed a stable emission property with a half-life of 6,000 h. Journal of Materials Science: Materials in Electronics Issue: 1 2008