Study of ballasting carbon nanotube field emitter arrays with coaxial gate using doped silicon resistor

One of the limitations of carbon nanotube (CNT) field emitter arrays (FEA) is the non-uniformity of total emission current contribution from each emitter due to geometry variation among CNT field emitters. We previously used a ballast resistor to ballast each emitter's current contribution to improve the reliability and stability of our CNT field emission (FE) cathode with coaxial gate. However, this approach has two main disadvantages: reduced FE current and enlarged power dissipation. In this paper, we improve the ballasting of our CNT FEA with coaxial gate using a doped silicon resistor. Each CNT field emitter is in series with a doped silicon resistor to avoid over current, based on the saturation of drift velocity in doped silicon. The FE current from each emitter can be limited at a desired current level based on the doping density and size of the doped silicon resistor. Those dominating emitter can be protected as gate voltage increases. The proposed approach is expected to improve our CNT cathode reliability and stability.