Relationship between Effective Work Functions and Noise Powers of Emission Currents in Nickel-Deposited Field Emitters

Abstract

Low-frequency current fluctuations in nickel-deposited field emitters were evaluated quantitatively with normalized noise power which was obtained by integrating the spectral density of the current fluctuation between the frequencies of 0.2 and 2 Hz. The distance between the emitter and the collector was adjusted to 1.5 µm, in order to realize an electrode spacing similar to those of vacuum microelectronics devices. Measurements were performed under an ultrahigh-vacuum environment. The obtained noise powers were analyzed with the Seppen-Katamuki chart which indicates the effective work function and apex radius of the emitter. It was found that the emitters with higher effective work functions showed higher noise powers. The results were explained qualitatively from the differential of the Fowler-Nordheim equation.