Improved On-State Performances of GaAs PCSS Based on an Optical Internal Reflection Structure

We demonstrate the positive role of an optical internal reflection structure (OIRS) in improving the on-state performances of gallium arsenide photoconductive semiconductor switch (GaAs PCSS). Herein, the structure consisting of a convex lens and two reflectors creates an effect of increasing the extrinsic absorbance. Under the same laser input, the PCSS employing this structure has achieved higher voltage output, faster switching and lower on-state resistance, which demonstrates at least 1.5-fold improvement in triggering efficiency, compared to the normal device. A two-dimensional (2D) device simulation has been performed and reveals that the positive effect of the OIRS is attributed to the accelerated formation of avalanche domains and the heightened carrier concentration, which are affected by the increased optical absorption.