In this paper, a three-layer GaAs photoconductive semiconductor switch (GaAs PCSS) is designed to withstand high voltage from 20 35 kV. The maximum avalanche gain and minimum on-state resistance of PCSS are 1385 0.58 Ω, respectively, which the highest values reported date. Finally, influence bias on stability analyzed. evaluated calculated. results show that jitter at voltages 30 kV 164.3 ps 10...