Sub-200 kW Lateral Sapphire-Based Epitaxial GaN Photoconductive Semiconductor Switch

This letter proposes a lateral sapphire-based epitaxial gallium nitride photoconductive semiconductor switch and designs two packaging modes: front-illumination and back-illumination. Tests have shown that the dark-state withstand voltage of packaged devices exceeds 10 kV. The device is illuminated and triggered using a 355 nm wavelength laser, and the output photocurrent waveform is captured through a designed RF extraction circuit. A 39.5% enhancement in photocurrent is demonstrated by the back-illumination device compared to the front-illumination configuration under identical photoelectric conditions. In particular, high-voltage testing shows that the output current of the back-illumination device reaches 61 A, with an on-state resistance as low as 60 Ω and the output power delivered to a 50 Ω matched load is 186 kW under 2 mJ laser energy and 7 kV bias voltage.