Current Filamentation in bulk GaAs Photoconductive Semiconductor Switches

Current filamentation during the high gain or non-linear switching mode in GaAs photoconductive semiconductor switches (PCSS) was reported in many papers. Optical properties which influence triggering include wavelength, temporal width, spatial size, and uniformity. The most important electrical property is the initial field produced across the switch. In this paper a high speed camera is used to monitor the infrared photoluminescence of the filaments during fast initiation of high gain switching for bulk GaAs PCSS (e.g. 15x6x3 mm(3)). The dependencies of the location of the current filaments on the optical properties including spatial size, uniformity and the electrical properties of the initial field produced will be discussed.