An ultra-responsive gold-nanoparticle-functionalized MoS2/GaSe/Ga2O3 heterostructure for self-powered broadband photodetection

Abstract

Conventional photodetectors have limitations in spectral range and efficiency; incorporating them with diverse materials could help overcome these constraints by enabling broadband, self-powered detection across the UVC to NIR spectrum. The MoS₂/GaSe/Ga₂O₃ heterostructure demonstrates optimized band synchronization and substantial optical absorption, significantly boosting detection efficiency over a broad optical spectrum. MoS₂ possesses direct bandgap properties and high electron mobility, while GaSe exhibits excellent carrier mobility and optical absorption. In addition, Ga₂O₃ features a wide bandgap and exceptional UV detection capabilities. The fabricated device exhibited an ultra-high responsivity of 14.45 A W⁻¹, with a response speed of 21 ms/54 ms at a 0 V applied bias under 266 nm light irradiation. It also showed a maximum responsivity of 6.40 A W⁻¹ and 10.75 A W⁻¹ under 625 nm and 1064 nm light irradiation at 0 V applied bias. Furthermore, the device surface was functionalized to create localized plasmon hot electrons, which enhances the generation of hot electrons through the decay and excitation of surface plasmons. This process yields a remarkable 153% enhancement in photodetector performance due to localized surface plasmon resonance effects that improve light absorption and carrier generation in the heterostructure. This work paves the way for developing MoS₂/GaSe/Ga₂O₃-based broadband photodetectors suitable for high-performance, self-powered optoelectronic devices.