Effects of bonding materials in screen-printing paste on the field-emission properties of carbon nanotube cathodes

The effects of bonding materials in screen-printing paste on field-emission properties were investigated with respect to high-efficient carbon nanotube (CNT) cathodes. The materials used to bond the CNTs to the cathode were composed of an insulating glass frit and a conducting Ag paste. The dependence of the electrical conductivity of the CNT paste, bonding material, and CNT ink on the field-enhancement factor was investigated using the Fowler–Nordheim equation. The emission current from the CNT cathode as the result of an electron tunneling effect was increased with increasing ratio of the dielectric glass-frit fraction in the CNT paste. The larger emission current of CNT cathode containing insulating-bonding materials can be attributed to a combination of the increased effective height of the CNTs, which protrude over the film in the cathode, and an increased field-enhancement factor.