Maximizing One-Dimensional Porous Emitter Packing Density for Electrospray Applications

The emitted current as a function of applied voltage has been investigated for linear electrospray emitter arrays of different emitter separation distances. The emitter arrays were fabricated out of porous tungsten using conventional micro fabrication techniques adapted for use on porous substrates. Experimental results are provided for samples of each emitter density and show that the emitter arrays produce between 0.5 to 1.5 μA of current per emitter. A normalization scheme is implemented to directly compare data between emitters with different geometry and emitter densities. Numerical simulation results were used to account for reductions in the electric field at the emitter tip due to close emitter packing. The normalized data shows that each sample emits similar current per emitter. This result highlights the potential for electrospray clustering and miniaturization. Finally, details about current research in creating two dimentional emitter arrays is discussed.