Structure Engineering of Ga2O3 photodetectors: A Review

Abstract Deep ultraviolet (DUV) photodetectors play important roles in the modern semiconductor industry due to their diverse applications in critical fields. Wide bandgap semiconductor Ga 2 O 3 is considered as one promising material for highly sensitive DUV photodetectors. However, the high responsivity of Ga 2 O 3 DUV photodetectors always comes at the expense of its response speed. Material engineering for high-quality Ga 2 O 3 materials can optimize the photoresponse performance but at the cost of much more complex process. Structure engineering can efficiently improve the performance of Ga 2 O 3 photodetectors based on various physical mechanisms. Owing to the increased modulation probabilities, part schemes of structure engineering even alleviate the tough requirements on Ga 2 O 3 material quality for high-performance DUV photodetectors. This article reviews the recent efforts in optimizing the performance of Ga 2 O 3 photodetectors through structure engineering. Firstly, photodetectors based on Ga 2 O 3 nanostructures and metasurface structures with nanometer size effect are discussed. In addition, junction structures of Ga 2 O 3 photodetectors, which effectively promote carrier separation in the depletion region, are summarized based on a classification of Schottky junction, heterojunction, phase junction, etc. Besides, Ga 2 O 3 avalanche photodiodes, offering ultra-high gain and responsivity, are focused as a promising prototype for commercialization. Furthermore, field effect phototransistors, based on which the scalability and low power performance of Ga 2 O 3 photodetectors have been well proven, are analyzed in detail. Moreover, auxiliary-field configurations with extra tunable dimensions for Ga 2 O 3 photodetectors are introduced. Finally, we conclude this review and discuss the main challenges of Ga 2 O 3 DUV photodetectors from our perspective.