Gate-Programmable Bipolar β-Ga2O3 Solar-Blind Phototransistor for Encrypted Optical Communication and Image Transmission

Abstract High-speed and reliable secure optical communication remains challenging because existing bipolar photodetectors either rely on slow electrochemical processes or require wavelength-selective excitation, resulting in limited processing speed, increased system complexity, and reduced communication reliability. Here, we demonstrate a gate-programmable solar-blind β-Ga2O3 phototransistor, in which gate-controlled reconfiguration of lateral and vertical carrier transport enables reversible switching of current polarity under only a fixed 254 nm solar-blind illumination wavelength. The device exhibits a responsivity of 1.73 × 104 A/W, a detectivity above 1014 Jones, and a millisecond response time, outperforming most previously reported photoelectrochemical-type and solid-state bipolar photodetectors in terms of combined sensitivity, speed, and operational simplicity. Benefiting from the electrically programmable bipolar response, the phototransistor further realizes fast XOR logic functionality, enabling encrypted text communication and image encryption/decryption under solar-blind ultraviolet illumination. This work establishes a high-performance β-Ga2O3 optoelectronic platform integrating solar-blind photodetection, logic operation, and information security, providing a promising hardware solution for next-generation secure optical communication systems.