A planar-type cold cathode that has a thin film diode structure, such as a metal-oxide-semiconductor tunneling cathode, produces highly directional emission and is insensitive to environment in contrast with a field emission cathode. The authors fabricated the planar cathodes based on nanocrystalline silicon covered with a thin oxide film prepared by pulsed laser ablation and examined the emission uniformity. The electron emission from the cathode with thin gold metal occurred around the edge of the emission area where it was surrounded with contact metal of thick aluminum, while electrons were emitted near the center of the area in the cathode with thin platinum. Afterward, the electron emitted area extended to the whole emission area with increasing the gate voltage. Scanning electron microscopy images showed discontinuous island structures of gold film and continuous and dense of platinum. The results demonstrated that emission uniformity was strongly dependent on morphology and resistance of thin metal.