Characterization of LED Driven GaN-based Photoconductive Switches

This paper presents the characterization of a carbon-doped gallium nitride (GaN) photoconductive semiconductor switch (PCSS). A novel method was devised to study the devices’ dynamic behaviour using a Cascaded Double Pulse Test (C-DPT), which utilizes commercial off-the-shelf (COTS) near-ultraviolet LEDs as the optical trigger. The C-DPT setup enabled evaluation of the turn-on and turn-off dynamics of lateral GaN PCSS devices, thereby demonstrating proof-of-concept for the proposed dynamic characterization method. While carbon doping has proven effective in achieving high resistivity and reducing leakage currents, the study identifies challenges posed by deep-level carbon traps, which significantly prolong the turn-off time. Additionally, the results highlight the important role of optical intensity in driving the turn-on of the PCSS. These findings emphasize the need to explore alternative impurities and high-power UV LEDs for improved switching performance. This work provides valuable insights into optimizing and characterizing GaN PCSS devices for advanced power electronics applications.