Cathodes for Futuristic THz VEDs

The development of terahertz (THz) technology has garnered significant attention due to its potential applications in communications, imaging, and spectroscopy. Central to the advancement of THz vacuum electron devices (VEDs) are electron emitters, which play a pivotal role in determining the efficiency and performance of these devices. This article details the advancements in electron emitter technology at CSIR-CEERI, focusing on thermionic and field emission cathodes essential for next-generation VEDs. The study examines Controlled Porosity Dispenser (CPD) cathodes, Nano-Scandate cathodes, and free-standing graphene film emitters. CPD cathodes demonstrate enhanced emission uniformity and efficiency through optimized pore structures. The fabrication of nano-scandate cathodes, utilizing scandia-doped tungsten nanoparticles, achieves high current densities at lower operating temperatures, extending the cathode’s lifespan. The introduction of tungsten-doped reduced graphene oxide (rGO) films as field emitters presents a significant improvement in emission performance, offering potential applications in advanced THz devices. Analytical and emission studies confirm the superior performance of these cathodes, positioning them as crucial components in the evolution of high-power, high-frequency VEDs.