Localized surface plasmon resonance-driven 71.9% EQE in Ga2O3 photodetectors: From photovoltaic enhancement to multifunctional optoelectronic logic gates integration

Ga₂O₃-based photodetectors with dual-band response characteristics hold great promise for realizing multifunctional optoelectronic logic gates (OELGs) in digital computing and secure communication. In this work, a hybrid organic-inorganic heterojunction based on PEDOT:PSS/Pt NPs/Ga₂O₃/GaN is designed to overcome the zero-bias performance bottleneck of conventional Ga₂O₃ heterojunction photodetectors and to integrate multiple logic operations into a single device. Under 254 nm illumination and 0 V bias, the device achieves an ultra-high external quantum efficiency (EQE) of ∼71.9% via the localized surface plasmon resonance (LSPR) of platinum (Pt) nanoparticles (NPs) embedded at the PEDOT:PSS/Ga₂O₃ interface. Statistics from twelve additional devices yield a median EQE of 71.3%. When an external bias is applied, the photodetector exhibits a tunable dual-band response in the UVC and UVA regions. By programming the bias voltage and optical inputs, six reconfigurable logic functions (NOR, NOT, NAND, XNOR, OR, and AND) are realized within a single unit, demonstrating its potential for parallel optical computing. Additionally, an encryption communication system based on these OELGs validates their applicability in secure data transmission, where dual-band signals can be dynamically encoded and decoded.