Catalyst‐Free Polymorphic β‐Ga₂O₃ Nanomaterials for Solar‐Blind Optoelectronic Devices: Applications in Imaging and Neural Communication

The continuous advancements in ultraviolet-C (UV-C) optoelectronics are poised to meet the growing demand for efficient and innovative optoelectronic devices, particularly in image sensing and neural communication. This study proposes a low-cost tube sealing and muffle calcination process for the catalyst-free synthesis of polymorphic β-Ga₂O₃ nanomaterials. These nanomaterials are synthesized via a vapor-solid (VS) growth mechanism, enabling the formation of high-quality nanowires (NWs), nanobelts (NBs), and nanosheets (NSs). UV-C photodetectors (PDs) fabricated with β-Ga₂O₃ nanobelts demonstrated exceptional performance, exhibiting a responsivity of 4.62 × 10⁵ A W^-1 and a specific detectivity of 4.78 × 10¹² Jones under 254 nm light. This PD enabled high-sensitivity and high-contrast UV-C imaging, effectively capturing the letters "CNU" and a "Panda" pattern. Additionally, the β-Ga₂O₃ nanowire-based optoelectronic synapse (OES) device displayed efficient light sensing and significant persistent photoconductivity, accurately mimicking synaptic behaviors such as short-term to long-term memory transitions and memory reinforcement. The OES device is successfully integrated into a wireless optical communication system, effectively simulating neural signal transmission by outputting the current waveform signal of "CNU 1954" and exhibiting notable UV-C light sensing and learning abilities. This work not only introduces a method for synthesizing polymorphic β-Ga₂O₃ nanomaterials but also underscores their potential in advanced UV-C optoelectronic applications, including image sensing and neural communication.