Influence of the interelectrode distance in electrophoretic cold cathode fabrication on the emission uniformity

In the present work, we studied the influence of the distance between electrodes in the electrophoretic process of flat cold cathode fabrication on the uniformity of the emission centers distribution. As the emitting material, we used single-wall carbon nanotubes. We found that the uniformity of field emission strongly depends on the distance between electrodes during the electrophoretic deposition. The best results have been achieved when the distance was smallest within the limits of the studied range (0.3–1.8 cm). For the high distances (1.1–1.8 cm), most of the emission sites were located on the edges of the cathodes. Good uniformity of field emission current has been achieved for the cathodes deposited with interelectrode distance equal to 0.3 cm. The cathodes were tested in the diode construction with the cathode–anode gap of 200 μm. Uniform light emission was obtained after the short training in the vacuum chamber. The turn-on voltage was 600 V, and the maximum achieved current was 850 μA at an applied voltage of 1.3 kV.