Influence of the composition of a NbNx thin-film field emitter array on emission characteristics

We fabricated ${\mathrm{NbN}}_x$ thin-film field emitter arrays by the ion beam assisted deposition technique which can prepare transition-metal nitride thin films at a relatively low temperature of about 500 °C. The emitter arrays were fabricated by depositing ${\mathrm{NbN}}_x$ thin films on Si cones. The nitrogen composition of the film is controlled by selecting the deposition condition, such as the arrival rate ratio of N to Nb flux. We investigated the influence of the nitrogen composition of the ${\mathrm{NbN}}_x$ thin-film field emitter arrays on electron emission characteristics. The emitter arrays with a higher nitrogen composition emitted electrons at a lower voltage and showed more stable emission than those with a lower composition. We compared the emission stability of the ${\mathrm{NbN}}_x$ emitters with that of the Si emitters. The emission from the NbN emitter (composition ∼1.0) was more stable than that from the Si emitter by a factor of 10 in terms of the noise power.