High-throughput ionic liquid electrospray sources based on dense monolithic arrays of emitters with integrated extractor grid and carbon nanotube flow control structures

We report the design, fabrication, and experimental characterization of externally-fed, batch-microfabricated electrospray emitter arrays with integrated extractor grid and carbon nanotube flow control structures for low-voltage and high-throughput electrospray of the ionic liquid EMI-BF₄ in vacuum. The conformal carbon nanotube forest on the emitters provides a highly effective wicking structure to transport liquid up the emitter surface to the emission site at the tips. Arrays containing as many as 81 emitters in 1 cm² were tested and emission currents as high as 5 μA per emitter in both polarities were measured, with a start-up bias voltage as low as 520 V. Imprints formed on the collector electrode and per-emitter IV characteristics showed excellent emission uniformity.