Challenges and opportunities in Ga2O3 solar-blind photodetectors: From material engineering to device realization

Abstract

Ultraviolet (UV) photodetectors have attracted extensive attention in both civilian and military applications due to their critical roles in environmental monitoring, flame detection, missile warning, and space communication. Among various UV-sensitive materials, Ga₂O₃ has emerged as a highly promising candidate owing to its ultra-wide bandgap (4.7-4.9 eV), excellent thermal and chemical stability, strong radiation hardness, cost-effectiveness, and high transparency to visible light. Its bandgap precisely corresponds to the solar-blind UV region (λ < 280 nm), enabling intrinsic solar-blind photodetection without the need for optical filters. This review focuses on the recent progress of Ga₂O₃-based solar-blind UV photodetectors, emphasizing the relationship between intrinsic material properties and device performance. It first outlines various growth techniques for Ga₂O₃ with different crystal orientations and discusses their influence on crystal quality and defect control. Subsequently, recent advances in Ga₂O₃ photodetector architectures including metal-semiconductor-metal devices, Schottky photodiodes, heterojunctions, and phototransistors-are comprehensively reviewed, with comparative analyses of their operational mechanisms and performance metrics. Furthermore, the development of Ga₂O₃-based avalanche photodiodes is highlighted as a key step toward practical, high-gain solar-blind photodetection. Finally, the review summarizes current challenges and future directions, focusing on doping control, defect engineering, and heterostructure design to optimize device performance and enabling large-scale applications.