Improved field emission properties of carbon nanotube cathodes by nickel electroplating and corrosion

Carbon nanotube ( CNT) cathodes prepared by electrophoretic deposition were treated by a combination of nickel electroplating and cathode corrosion technologies. The characteristics of the samples were measured by scanning electron microscopy, energy dispersive X-ray spectroscopy, J -E and F-N plots. After the treatment, the CNT cathodes showed improved field emission properties such as turn-on field, threshold electric field, current density, stability and luminescence uniformity. Concretely, the turn-on field decreased from 0.95 to 0.45 V/mu m at an emission current density of 1 mA/cm(2), and the threshold electric field decreased from 0.99 to 0.46 V/mu m at a current density of 3 mA/cm(2). The maximum current density was up to 7 mA/cm(2) at a field of 0.48 V/mu m. In addition, the current density of the CNT cathodes fluctuated at around 0.7 mA/cm 2 for 20 h, with an initial current density 0.75 mA/cm 2. The improvement in field emission properties was found to be due to the exposure of more CNT tips, the wider gaps among the CNTs and the infiltration of nickel particles.