Investigation of Delay Jitter of Avalanche GaAs PCSS for Triggering High-Voltage Gas Switch

The delay jitter characteristics of gallium arsenide (GaAs) photoconductive semiconductor switches (PCSSs) triggered in avalanche mode were experimentally investigated under dc bias. In the dark-state measurement, the PCSS was tested under a 40-kV bias voltage to verify its withstanding voltage and reliability. In the ON-state measurement, the delay jitter time of PCSS at different triggering positions was measured. The experimental results showed that the shortest delay jitter time was obtained when the laser was applied to the middle position of the cathode electrode. To evaluate the long-time stability, the delay-jitter time was recorded after continuous shots. It shows an ascending trend in delay jitter time with the increase in operating shots. The degeneration of the delay jitter time of the PCSS was mainly attributed to the device damage, including electrode ablation and filament current ablation, which was verified by the analysis of scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). Furthermore, a bipolar high-voltage gas switch integrated with PCSSs was successfully triggered by a low-energy fiber laser.