A Multi-Layer Diamond Cathode for High Power Applications

A multi-layer diamond thin film field-emission cathode is proposed for high power applications such as UV lasers, high power switches, vacuum electronic devices and high--energy accelerators. The proposed optimization of various layers enables us to take advantage of high thermal conductivity of diamond to increase the maximum current obtained from each emission site thereby increasing the total current density. The proposed diamond cold cathodes developed using an integrated deposition-testing system will potentially offer higher stability, larger emission site density, and much higher lifetime than existing cold cathodes. Diamond's higher thermal conductivity, higher thermal diffusivity and lower sputter yield discourages thermal evaporation of emission sites, and thus reduces the possibility of catastrophic failure. UHV has constructed an innovative system whereby the cathodes can be deposited and tested without exposing them to air, and we propose to use this system to understand and optimize the emission site behavior. UHV will work with Sarnoff Corporation and Sandia Labs to successfully fabricate and analyze high power cathodes. Phase II will involve development of larger area cathodes for implementation in high power systems.