Space Charge Limited Transport in Si Field Emitter Arrays

Field emitter arrays (FEAs) are cold electron sources for applications such as radio frequency (RF), ion and xray sources. For any application, the current density is of utmost importance and it is the main figure of merit. Little work has been done to understand how to geometrically optimize the design of the anode in order to provide the optimal current drive for a given voltage. It is well-known that thermionic sources obey the 1D Child-Langmuir space charge limit which provides the geometrical design considerations. Here, we investigate the impact of the 1D Child-Langmuir law on Si FEAs by changing the cathode/anode distance. We report that Si FEAs obey the classical law with one slight modification.