All-Solution Fabricated MXene/GaAs Self-Driven Photodetector with an Inserted Graphene Oxide Interface Layer

As a novel two-dimensional material, MXene has attracted much attention due to its special photoelectric properties. The formation of van der Waals Schottky heterojunctions between MXene and bulk semiconductor materials is a promising method for manufacturing photodetectors. Furthermore, the deterioration in device performance resulting from the Schottky interfacial state can be effectively mitigated by implementing interface engineering techniques. In this study, we develop a Ti₃C₂T_<i>x</i>/GO/GaAs van der Waals Schottky junction photodetector with a graphene oxide interfacial barrier layer, which is fabricated using an all-solution method on a prepatterned substrate. The insertion of the GO interfacial layer effectively decreases the dark-current noise, thereby maintaining an ultralow dark current at zero bias, achieving a large specific detectivity of 1.4 × 10¹³ Jones and an ultrafast response speed of 41.7/40.0 μs. Moreover, the device exhibits a broad-band response spectrum spanning from 405 to 980 nm. The infrared photoresponse exceeding the absorption edge of GaAs results from the excitation of hot electrons by the plasmon effect in the MXene film. Due to the simple preparation and high specific detectivity, the Ti₃C₂T_<i>x</i>/GO/GaAs self-driven photodetector is suitable for the monitoring of weak light signals and can be used as the basis for many light detection applications.