Effect of degassed elements on the degradation behavior of carbon nanotube cathodes in sealed field emission-backlight units

The effect of degassed elements from the phosphor layer on a carbon nanotube (CNT) cathode was investigated. During the operation of field emission backlight units, it was found that zinc and sulfur were degassed from the phosphor anode. X-ray photoelectron spectroscopy analysis showed that sp(2) bonding in the CNTs changed to zinc-assisted sp(3)-like bonding, modified by the adsorption of the zinc. The change of the CNT structure to a nonhexagonal carbon network suggests that the electron emission from the degraded CNT tips decreases due to the higher work function of sp(3)-like bonding, compared to that of sp(2) bonding.