Research on Time Jitter of GaAs Photoconductive Semiconductor Switches in the Negative Differential Mobility Region

Time jitter of GaAs photoconductive semiconductor switches (PCSS) is investigated at an optical excitation of 1053-nm wavelength and 500-ps pulse duration. The experimental results indicate that the time jitter of the GaAs PCSS exhibits a nonmonotonic variation in the negative differential mobility (NDM) region. All of these time jitters are lower than 4% of the rise time of the switching waveform. The optimum time jitter of ~15 ps is achieved at the onset of the NDM region. The theoretical relationship between the optical excitation parameters, the bias electric field, and the time jitter of the GaAs PCSS is built up. The nonmonotonic behavior of the time jitter with electric field is attributed to the instability of the relative fluctuation of drift velocity caused by inter-valley transition of carriers in GaAs.