Achieving high photoelectric efficiency in an optimized vertical photoconductive device with 355 nm excitation

Abstract

This work demonstrates a high-efficiency, intrinsically triggered vertical photoconductive semiconductor switch using 355 nm laser excitation. The key is a zero-electrode-offset design where the electrode edges are aligned flush with the laser-incident sidewall. This geometry maximizes the effective contact area for collecting photogenerated carriers confined within a shallow (∼50 μm) surface layer, enabling efficient current spreading. Compared to a conventional planar structure, the optimized vertical device achieves over an order-of-magnitude reduction in on-state resistance at high optical intensity, reaching a remarkably low saturated resistance of 0.5 Ω at 10 MW/cm2. This performance surpasses that of extrinsically triggered vertical devices and advanced planar devices with n+ implantation, while operating at significantly lower optical intensity and without requiring complex doping processes. The results validate a promising strategy that combines the benefits of intrinsic triggering (high efficiency) and vertical architecture (robust current handling) for developing high-voltage, high-power pulsed electronics.