Domain engineered gallium oxide phototransistors enabling intelligent ultraviolet vision with dynamic gating

Abstract

Domain-induced carrier scattering and persistent photoconductivity (PPC) remain major bottlenecks in β-Ga₂O₃-based deep-ultraviolet (DUV) photodetectors, limiting their use in high-speed imaging, optical communication, and neuromorphic sensing systems. Here, we propose a materials–circuits co-design strategy that integrates crystallographic domain engineering with pulsed-gate modulation to overcome these challenges. Si-doped β-Ga₂O₃ thin films were epitaxially grown on 6° off-axis sapphire substrates, where atomic step edges induced single-domain alignment, resulting in improved lateral carrier transport and reduced leakage current compared with on-axis counterparts. Under comparable pulsed conditions, single-domain devices exhibited faster recovery than previously reported β-Ga₂O₃ phototransistors, highlighting the synergistic interplay between domain-engineered transport and dynamic gating. As a result, the devices achieved a high detectivity (D*) of 9.17 × 10¹⁵ Jones and a fast photoresponse of 0.7 ms under reset conditions, while maintaining stable and energy-efficient operation under sub-volt bias. Beyond individual devices, the optimized phototransistors were integrated into a 24 × 24 active-pixel array for system-level DUV imaging. Coupled with convolutional neural networks (CNNs), the array achieved accurate pattern recognition and image reconstruction, while synaptic depression and active reset processes enabled rapid afterimage suppression and image recovery. Overall, this work establishes a domain-engineered, pulse-modulated β-Ga₂O₃ phototransistor platform that unifies materials-, device-, and system-level innovations, providing a scalable and energy-efficient route toward intelligent ultraviolet vision.

Keywords

active pixel arrays / domain engineering / DUV imaging techniques / gallium oxides / low-power operations / neuromorphic visions

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