Sub-ohm on-state resistance LT-GaAs photoconductive switch for ultrafast pulse power technology

As a core component of ultrafast pulse power technology, the performance of photoconductive semiconductor switches is fundamentally limited by on-state resistance. To address this challenge, we demonstrate a low-temperature gallium arsenide photoconductive semiconductor switch (LT-GaAs PCSS) that achieves a minimal on-state resistance of 0.005 Ω, thereby extending the lifetime of the PCSS. This study employs numerical simulations and experimental methods to reveal the physical mechanism by which nonlinear critical conditions trigger the transition of the PCSS into a sub-ohm state. This phenomenon is attributed to the effects of carrier impact ionization, the spatial distribution of photo-generated carriers, and internal defect processes in the LT-GaAs material. Our work provides a foundation for the development of highly efficient, compact, and long-lifetime optical control devices.