The Development of a Micro-Fabricated CNT-Based Neutralizer for Micro-Propulsion Applications

This paper reports the preliminary development of a microand nano-fabricated carbon nanotube (CNT) –based electron source intended for micro-propulsion applications. The paper proposes a device that implements a trade-off between microfabrication complexity and performance using a 3D packaging technology to minimize interception and decouple the process flows of the grid and the emitter array. The device uses plasma enhanced chemical vapor deposited (PECVD) CNTs as field enhancers. The PECVD CNT growth is documented, and IV characteristics of the emitted current from a micro-/nano-structured emitter substrate are provided. A maximum emitted current of 71 μA @ 480 V is obtained from a 0.25 cm estimated active emitter area and a grid with 200 μm separated 50 μm from the emitters. The electron source emission can be described by the Fowler-Nordheim theory, and a field enhancement of 3.69×10/cm –corresponding to an emitter tip radius of 27 nm.