The relation between the work function and current fluctuation was investigated for various kinds of emitters: element metals, transition metal nitrides, and diamonds. Since these deposited emitters have no good standard, if is difficult to distinguish the effect of work function and the other physical parameters such as apex radius. in order to distinguish these effects, we propose a unique technique of the SK chart and plotting the Fowler-Nordheim characteristics in the SK chart in accordance with the magnitude of the noise power: SKN plot. The SKN plot deafly exhibits the relation between physical parameters and current fluctuation and it was found that the emitter with lower work function shows lower current fluctuation.