A mode for the periodicity and weakening surge in semi-insulating GaAs photoconductive semiconductor switches is proposed based on the transferred-electron effect. It is shown that the periodicity and weakening surge is caused by the interaction between the self-excitation of the resonant circuit and transferred electron oscillation of the switch. The bias electric field （larger than Gunn threshold） across the switch is modulated by the AC elec-tric field,when the instantaneous bias electric field E is swinging below Gunn electric field threshold ET but grea-ter than the sustaining field Es （the minimum electric field required to support the domain） at the time of the do-main reaching the anode, and then the delayed-dipole domain mode of switch is obtained. It is the photon-activated carriers that satisfy the requirement of charge domain formation on carrier concentration and device length prod-uct of 10^12 cm^-2,and the semi-insulating GaAs photoconductive semiconductor switch is essentially a type of pho-ton-activated charge domain device.
Given is the experiment results in which the laser pulses of 1 046 nm and 532 nm are used to trigger the semi-insulation GaAs photoconductive semiconductor switch(PCSS) with an electrode distance of 4 mm. And made is an analysis of the switchs photovoltaic response characteristics under the high gain mode when the biased field is bigger than the Geng effect field. Also a theory is presented that the main reason for the photovoltaic pulse response delay is the transmission of charge domain, caused by the presence of EL2 energy level in the chip material. Finally, the transmission time of charge domain is calculated and a result that inosculates with the experiment is attained.
The quenched domain mode of the photo-activated charge domain （PACD） in semi-insulating （SI） GaAs photoconductive semiconductor switches （PCSSs） is observed. We find that the quenched domain is induced by the instantaneous electric field across the PCSS being lower than the sustaining electric field of the domain during the transit of the domain. The extinction of the domain before reaching the anode can lead to a current oscillation frequency larger than the transit- time frequency when the bias electric field is lower than the threshold electric field of the nonlinear PCSS. According to the operation circuit and the physical properties of a high-field domain,an equivalent circuit of the quenched domain is presented. The equivalent circuit parameters including capacitance, resonant frequency, and inductance are calculated and measured. Our calculations agree well with the experimental results. This research provides theoretical and experimental criteria for heightening the oscillation frequency and efficiency of PACD devices.
