A Review of Ga₂O₃ Heterojunctions for Deep‐UV Photodetection: Current Progress, Methodologies, and Challenges

In recent years, gallium oxide (Ga 2 O 3 ) has drawn considerable research interest as an ultrawide‐bandgap semiconductor due to its promising applications in the power electronics, photodetection, and gas sensing. Moreover, Ga 2 O 3 heterojunctions have emerged as a promising approach to address key limitations of Ga 2 O 3 as a standalone material—most notably, its lack of p‐type doping capability. One of the key application areas for Ga 2 O 3 and its heterojunctions is ultraviolet (UV) photodetection, which has gained significant attention yet remains a relatively nascent field with vast potential for further exploration and optimization. This review provides a detailed overview of the current state‐of‐the‐art in Ga 2 O 3 technology, highlighting recent research advancements, key challenges, and emerging strategies aimed at overcoming these challenges. Specifically, it examines Ga 2 O 3 heterojunctions for deep‐UV photodetection, analysing compatible electrode materials and assessing various substrates suitable for Ga 2 O 3 growth to enhance device performance. This comprehensive review is designed to serve as an essential resource for researchers and engineers working with Ga 2 O 3 ‐based heterojunctions, especially for applications in UV photodetection. Written with the needs of new entrants in mind, it aims to build a robust foundational understanding of Ga 2 O 3 technology, supporting ongoing innovation and application expansion in this field.