Ultraresponsive, Self-Driven Broadband (UVC-NIR) Photodetector Based on Localized Surface Plasmon Enhanced MoS₂/GaSe/Ga₂O₃ Heterostructures

Innovation in photodetector technology is reported by developing a novel MoS₂/GaSe/Ga₂O₃ heterostructure on Si substrate, capable of detecting a broad spectral range from UVC to NIR. The heterostructure device was designed via sputtered deposition of MoS₂ and Ga₂O₃ films and GaSe via chemical vapor deposition. MoS₂ offers high electron mobility and direct bandgap, GaSe provides high optical absorption and good carrier mobility, while Ga₂O₃ features a wide bandgap and excellent UV detection capabilities. Integrating these materials within the heterostructure addresses the growing demand for broadband photodetection. The fabricated device exhibited ultrahigh responsivity of 14.7 A/W with a response speed of ~ 20 ms under self-driven condition (zero applied bias) for an optical illumination of 266 nm. The device also demonstrate a maximum responsivity of 3.2 A/W and 4.3 A/W under 532 nm and 1064 nm light illuminations at zero applied bias. Further, the functionalization of the heterostructure surface with mono-dispersed Au-nanoparticles (5nm) led to the generation of hot charge carriers through the excitation and decay of surface plasmons. The fabricated surface functionalized heterostructure photodetector exhibits a remarkable 3500% enhancement in responsivity, attributed to localized surface plasmon resonance (LSPR) effects that augment light absorption and carrier generation within the heterostructure. This study paves the way for developing MoS₂/GaSe/Ga₂O₃-based broadband photodetectors for developing high-performance, self-driven optoelectronic devices.