Output characteristics of GaAs photoconductive semiconductor switch at high bias voltages

A photoconductive semiconductor switch (PCSS) with a gap of 2 mm was fabricated on a semi-insulating GaAs substrate. The PCSS was excited by a 1064 nm wavelength pulse laser which has 700 ps pulse width (FWHM) and energy of 135 µJ. Output pulses of the PCSS were recorded at bias voltages from 100 V to 1.4 kV in fluorinert ambience which has high dielectric strength (Eb > 160 kV/cm). At bias voltages below 1 kV, the PCSS exhibited the linear operational mode, where the output pulse amplitude linearly increases with the increased bias voltage. When the bias voltage gets higher than 1 kV, the output pulse amplitude begin to increase more rapidly due to nonlinear optical process. The pulse width and fall time of the output pulses increased correspondingly.