Study On Characteristics Of 30kv/50a Gallium Arsenide Photoconductive Switch With Low Light Energy

With the gradual expansion of the application field of pulse power technology,there is a higher requirement for photoconductive switches,using micro-focus levels.The weak light triggering photoconductive switch to generate ultra-fast electric pulse is a hot research topic in this field.Based on the structure and characteristics of GaAs photo-conductive semiconductor switches(GaAs PCSS),the suitable gap value and chip shape of photoconductive switches under high bias voltage are developed.The photoconductive switch is required to work in the bias voltage of 30kV and above.Therefore,insulating oil is used as a further insulation measure,which effectively improves the withstand voltage of the 11mm heterodyne photoconductive switch to 45kV.A fiber-coupled laser diode(LD)is used as the trigger source.When the bias voltage is up to 35kV,the photoconductive switch output amplitude is small and in linear operation mode.The factor that causes the switch to enter nonlinearity is found to be related to the density of the light energy that triggers the light energy value,and the trigger light energy density of the photoconductive switch is increased by twice.Using a pulsed nanosecond laser as the trigger source,the switch enters a nonlinearity and successfully outputs a current amplitude of up to 61.1 A.Calculating the minimum light energy density based on the carrier density threshold entering the nonlinearity is basically consistent with the experimental results.Among them,the phenomenon that the loop resistance value is smaller than the series resistance is guessed because the resistance value changes due to the change of the magnetic field.And the on-resistance value of the switch is very small,only on the order of sub-ohms.