High-current Field Emitter Arrays for Directed Energy Weapons

Field-emission electron-emitting arrays hold promise for use in high current-density electron-beam devices as replacement for power consuming thermionic emitters. Large field-emitter arrays, however, are limited in total current due to non-uniformity and resulting instability problems. As a solution to these problems current-limiting devices, such as a field-effect transistor (FET) for each emitter site were considered in the Phase I program. The results have shown the feasibility of this approach, including the demonstration of significant total currents from uncontrolled emitters, and development of a fabrication scheme extendable to arrays of 1 cm2 area for an expected total controlled current of 1 A. ISSI, in cooperation with the University of Southern California (USC), proposes to further develop, fabricate and test, both experimentally and by modeling, large arrays of FET-controlled, carbon-nanotube field-emitter devices to meet the required total current at a current density of 1 A/cm2.