Time-Dependent Analysis of High-Gain Triggering in Semi-insulating GaAs Photoconductive Switches

The transient transport of photo-generated carriers and temporal variation of the built-in field, during triggering in semi-insulating GaAs photoconductive switches, have been investigated by using a special Monte Carlo particle simulator. It shows that the built-in field can exceed the intrinsic avalanche field of semi-insulating GaAs under certain optical and electrical condition. In such a case, local breakdown ionization is considered to be responsible for the transition in GaAs high-gain switching. The optical and electrical triggering thresholds are calculated and the calculated values of optical and electrical thresholds and partial delay time are in agreement with the published experimental data.