MXene/RGO/Si Schottky Junction for a High-Performance Self-Powered Broadband Photodetector

Two-dimensional (2D) materials are attractive for self-powered photodetectors, but their practical use is often hindered by unstable interfaces, inefficient carrier extraction, and poor environmental durability. Ti₃C₂T_x-MXene offers high electrical conductivity yet suffers from oxidation-induced instability, whereas reduced graphene oxide (RGO) provides better structural robustness but limited interfacial charge transport capability when used alone. In this work, the Ti₃C₂T_x-MXene/RGO/Si Schottky junction photodetector was fabricated based on a hybrid interfacial engineering strategy, in which Ti₃C₂T_x-MXene and RGO are integrated as a multifunctional Schottky-contact layer. This hybrid interface simultaneously promotes carrier extraction, suppresses dark current, and improves device stability under self-powered operation. Compared with the Ti₃C₂T_x-MXene/Si device, the Ti₃C₂T_x-MXene/RGO/Si photodetector exhibits markedly enhanced zero-bias performance, including an on/off ratio of 1.48 × 10³, a responsivity of 1.82 × 10² mA W^-1, and a specific detectivity of 2.37 × 10¹⁰ Jones under 368 nm illumination, corresponding to 22.5-, 10.1-, and 24.2-fold improvements, respectively. In addition, the rise and fall times are shortened to 12 and 18 ms, respectively. n-Si serves as the dominant photogeneration medium, and the Ti₃C₂T_x-MXene/RGO hybrid layer mainly functions as an interfacial carrier-separation and collection layer. The hybrid structure also improves the operational stability of the device under ambient conditions. These results demonstrate that Ti₃C₂T_x-MXene/RGO hybrid interfacial engineering is an effective strategy for addressing the performance-stability trade-off in Si-based self-powered Schottky photodetectors.