Preparation and Performance Optimization of Boron-gallium Co-doped Zinc Oxide Transparent Electrodes

Silicon carbide (SiC) photoconductive semiconductor switches (PCSS) are optoelectronic devices that utilize ultrafast pulsed lasers to modulate semiconductor resistivity for switching operations. Transparent oxide conductive films, especially zinc oxide thin films, are considered as a potential alternative electrode materials to reduce the on-resistance due to their excellent optical transparency and electrical conductivity. However, zinc oxide thin films are prone to ablation damage under high-energy pulsed laser irradiation, leading to crack formation and significantly affecting the device’s lifespan. Additionally, uneven local electric field distribution in the electrodes poses challenges to the long-term stability of the device. In this study, boron-gallium co-doped zinc oxide (BGZO) thin films were prepared by magnetron sputtering, and effects of annealing temperature (300-600 ℃) on their structural and electrical properties were investigated. X-ray diffraction and Hall effect measurements revealed that these films annealed at 400 ℃ exhibited optimal crystallinity and electrical performance, achieving a visible-light transmittance of 93% and a resistivity as low as 1.40×10-2 Ω·cm. After integrating the optimized BGZO films as transparent electrodes into SiC PCSS devices, these BGZO-based devices, under 532 nm wavelength and 170 mJ pulsed laser excitation, exhibited more stable operation than conventional Ni-based electrodes, with reduced filamentary current damage at the SiC-electrode interface and improved electric field uniformity at the electrode edges. This study provides an optimized fabrication strategy for high-performance transparent conductive films and confirms their advantages in PCSS applications.