Evaluation Of Transport Effects On The Performance Of A Laser-controlled GaAs Switch

The attempt to use bulk, semiconductor-based photoconductive devices as compact switches in demanding pulsed power applications has been limited by breakdown phenomena variously described as "thermal runaway," "surface flashover," and "lock-on," all forms of non- ohmic conduction. We present a summary of experimental observations related to optically induced non-ohmic current-voltage characteristics in semi-insulating semiconductors and integrate these observations into a revised power scaling criteria for bulk photoconductive semiconductor switches. We pursue an argument that unifies these observations with the physical mechanisms of charge-transport in the bulk and contact related phenomena at the device boundaries.