This line of research looks to exploit physical phenomena that cause a flow of electrons using field enhancing structures. The field enhancing structures, i.e., field enhancers, use low voltage to set a high electrostatic field that can produce quantum tunneling of electrons from (field emission) or into (field ionization) surfaces of metals or semiconductors. There is a wide variety of applications that can benefit from this exciting research effort including portable analytical instruments (gas ionizers), neutralizers for ion-based space engines, high-frequency vacuum amplifiers, multi-electron beam lithography, and portable X-rays sources that don’t use radioactive isotopes. I have focused my research in using silicon tips and vertically aligned multiwalled carbon nanotubes (MWCNTs) to implement field enhancers. On the one hand, silicon tips can have tip diameters that are up to an order of magnitude smaller than the diameter of MWCNTs, and process flows for fabricate silicon tips are easier to integrate with common microfabrication technology. On the other hand, MWCNTs are far more resistant than silicon tips to oxygen and high-pressure operation, and they can potentially emit more current per emitter before burning out.