Analyzing the Effects of Aluminum-Doped ZnO and Ag Layers for the Transparent Electrode Vertical PCSS

To figure out the effects of aluminum-doped ZnO (AZO) and Ag layers for the transparent electrode vertical (TEV) photoconductive semiconductor switch (PCSS) reported in our previous works, several different structures of high power, new vertical, extrinsic-triggered PCSS were designed and their performances are presented. All the PCSSs were fabricated on the vanadium compensated semi-insulating (VCSI) 4H-SiC substrates. The ON-state performance of all device versions was characterized by a test circuit without load resistor. Among all structures, the version with AZO transparent window, AZO subcontact layer, and silver mirror reflector has been testified to be the most reasonable structure, and shows the best results as well. Its minimum ON-state resistance is $6.11~\Omega $ at the optical power density of 2.62 MW/cm2. The factor for the best ON-state performance of this structure is attributed to the improvement of utilization efficiency of laser energy, and good contact between the AZO and SiC substrate.