Design of a GaAs Photoconductive Semiconductor Switch for Reliable Triggering of a Gas Switch

A novel photoconductive semiconductor switch (PCSS) with a field-shielding conductor was designed to homogenize the electric field at the electrode edge, thereby enabling reliable triggering of a high-voltage gas switch. The structure of the field-shielding conductor incorporated PCSS (Con-PCSS) was optimized by simulating the electrostatic field. The results indicated that a significant electric field enhancement appeared at the electrode edge of the pristine PCSS (P-PCSS), causing device failure, whereas the electric field distribution in the Con-PCSS was relatively uniform. Compared to the P-PCSS, the Con-PCSS demonstrated superior performance with a higher withstanding voltage and lower dark current. It was found experimentally that the Con-PCSS exhibited nearly stable current and weak damage over 10 000 shots, whereas the P-PCSS exhibited current decay and severe damage after only 4000 shots. Additionally, a ±80-kV gas switch integrated with the Con-PCSS was successfully triggered by a low-energy fiber, showing a stable switching delay time over 8000 continuous shots.