Integrating photodetection and neuromorphic vision in ALD-grown amorphous Ga₂O₃ thin films via bias-voltage modulation

We demonstrate what we believe to be a new atomic layer deposition (ALD) process utilizing gallium chloride (GaCl₃) and water vapor as complementary precursors for synthesizing high-quality Ga₂O₃ thin films. The developed process enables the growth of ultrasmooth amorphous Ga₂O₃ layers with sub-nanometer surface roughness and an ultrawide bandgap of 5.29 eV, ideal for deep-ultraviolet (DUV) photonic applications. Metal-semiconductor-metal (MSM) photodetectors employing the Au/Ga₂O₃/Au architecture achieve exceptional performance metrics, including an outstanding photocurrent ratio of 98.36 under 254 nm illumination and ultrafast response characteristics (0.23 s rise/0.25 s decay times). The devices exhibit unique bias-tunable dual-mode operation: low-voltage operation enables conventional fast-response photodetection, while high bias conditions induce persistent photoconductivity effects. This voltage-dependent reconfigurability allows effective emulation of neurobiological functions, particularly demonstrating paired-pulse facilitation and replicating sophisticated learning-forgetting-relearning cognitive processes. Our findings establish ALD-grown Ga₂O₃ as a versatile platform for developing multifunctional optoelectronic systems that synergistically integrate high-performance DUV detection with neuromorphic computing capabilities, paving the way for next-generation reconfigurable optical memory devices and bio-inspired visual processing architectures.