Structure engineering of Ga<sub>2</sub>O<sub>3</sub> photodetectors: a review
Wentao Wu, Hong Huang, Yilin Wang, Haoran Yin, Keju Han, Xiaolong Zhao, Xiao Feng, Yan Zeng, Yanni Zou, Xiaohu Hou, Zhongming Wei, Shibing Long
Abstract
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.