Comparative Study of Lateral and Vertical Beta-Ga2O3 Photoconductive Switches via Intrinsic and Extrinsic Optical Triggering

TL;DR

This study systematically compares lateral and vertical beta-Ga2O3 photoconductive switches under different optical excitations, revealing how device geometry and carrier generation influence performance for high-power applications.

Contribution

First experimental comparison of lateral and vertical beta-Ga2O3 PCSS under intrinsic and extrinsic optical excitation, highlighting the impact of device structure on switching performance.

Findings

Lateral PCSS performs better under intrinsic excitation.

Vertical PCSS excels under extrinsic excitation.

Device geometry and optical excitation type critically affect switch performance.

Abstract

Gallium oxide (Ga2O3), with its ultra-wide bandgap (approximately 4.8 eV) and high breakdown field (approximately 8 MV per cm), is a leading candidate for photoconductive semiconductor switches (PCSSs) in high-power and high-speed pulsed applications. This work, for the first time, presents a systematic experimental comparison of lateral and vertical beta-Ga2O3 PCSS under both intrinsic (245 nm) and extrinsic (280 nm, 300 nm, and 445 nm) optical excitation. Under intrinsic excitation, where carrier generation is confined near the surface due to the shallow absorption depth (approximately between 0.1 and 1 um), the lateral PCSS demonstrated higher photocurrent performance compared to the vertical structure. In contrast, under extrinsic excitation, which enables deeper penetration into the bulk, the vertical PCSS exhibited enhanced switching performance due to a more uniform electric-field distribution across the device volume. These results highlight the critical role of device geometry and carrier generation mechanism in optimizing Ga2O3 PCSS performance and provide valuable guidance for developing efficient and cost-effective high-voltage PCSSs.