The effect of hole current on the recovery characteristics of semi-insulating GaAs photoconductive opening switches

GalIium Arsenide (GaAs) photoconductive switches offer the possibility of serving as compact opening switches for dc voltage systems that require fast opening times (<100nS) and high voltage holdoff (> 10kV) . The voltage recovery characteristics of GaAs often exihibit Gunn effects, and instead of recovering to its initial off-state voltage, the device "locks-on" at Gunn threshold fields (/spl ap/2.5kV/cm). Measurements performed on semi-insulating Cr:GaAs photoconductive opening switches at dc voltages up to 10kV and current densities up to 100mA/cm/sup 2/ indicate that hole current may be a primary instigator of lock-on during voltage interruption, and that lock-on can be avoided in increasing the density of hole traps.