Progress in gallium arsenide photoconductive switch research for high power applications

Gallium arsenide (GaAs) photoconductive semiconductor switches (PCSS) have been studied as an enabling technology for a variety of applications at both the Air Force Research Laboratory and Sandia National Laboratories. High gain PCSS can be triggered with small laser diodes or laser diode arrays. The requirements of these applications require the switching of high voltage in sub-nanosecond time with low temporal jitter of the switches relative to the trigger laser. There have been several configurations and sizes of these switches studied by the Air Force Research Laboratory over the last several years. The most recent designs are with small structures where the electrical contacts are placed on opposite sides of the bulk material. This configuration allows for different electrical conditions on either side depending on the nature of the semiconductor structure; i.e., p-i-n or n-i-n. In addition to the type of structure used and geometry of the contacts, the performance of these switches (switch time, voltage, and jitter) is dependent on the thickness of the GaAs. Several thicknesses have been studied during the past year. This paper reports on the results of several studies to investigate the ultra-fast switching properties of these structures.