Optoelectronic Logic Gates and Chaotic Encryption Optical Communication Enabled by Dual-Band Optical Response in a-Ga2O3/Cr2O3 Heterostructures

Self-powered bipolar photodetectors (PDs) have garnered significant attention for their potential in optoelectronic logic gates (OELGs) and secure optical communication systems, owing to their extremely low power consumption and cost-effectiveness. However, conventional unipolar PDs are constrained by functional rigidity and their reliance on passive decoding circuits. In this study, a self-powered bipolar photoelectrochemical detector (PEC-PD) is presented with a wavelength-dependent photoresponse in electrolytes, based on an amorphous gallium oxide/chromium oxide (a-Ga 2 O 3 /Cr 2 O 3 ) p–n heterojunction. This distinctive behavior arises from variations in the competitive dynamics between interfacial redox reactions and photogenerated carrier transport at the semiconductor/electrolyte interface under short-wave ultraviolet (UV-C) and long-wave ultraviolet (UV-A) irradiation. The device exhibits a positive photocurrent response time of 82.1/91.2 ms under 254 nm illumination and a negative photocurrent response time of 9.1/13.6 ms under 380 nm without an external power supply. Utilizing this tunable photoresponse, five fundamental Boolean logic operations—“OR”, “AND”, “NOR”, “NOT”, and “NAND”—are demonstrated by tailoring the illumination at specific wavelengths. Furthermore, the distinct bipolar photocurrent behaviors enable encrypted optical communication within a single photoelectrode architecture. This study advances the understanding of carrier dynamics manipulation and provides a solid foundation for the development of multi-functional OELGs and secure optical communication systems.