kV-Class Photoconductive Semiconductor Switches Using Mn-Doped Semi-Insulating GaN Bulk Crystals

Photoconductive semiconductor switches (PCSSs) were fabricated using Mn-doped semi-insulating GaN substrates. The n+-GaN regions were selectively formed via Si-ion implantation followed by activation annealing, and Ti/Au was deposited as ohmic contacts. Current-voltage (I-V) characteristics of the GaN PCSSs were measured. Under monochromatic ultraviolet illumination (λ = 365 nm), a distinct photocurrent was observed that increased proportionally to optical power. Notably, the photocurrent was approximately 40 times larger than that of the Fe/C co-doped GaN PCSSs, reflecting the difference of carrier lifetimes. Under dark conditions, kV-class high breakdown voltages were demonstrated alongside low leakage current. These results showcase the significant potential of Mn-doped GaN PCSSs for high-power and high-speed power electronics applications free from electromagnetic interference (EMI).