High performance broadband self-driven photodetector based on MXene (Ti3C2Tx)/GaAs Schottky junction

As a novel family of 2D materials, MXenes are supposed to play a vital role in optoelectronic devices and systems due to their high conductivity, good optical properties, and favorable compatibility with water and organic solvents. However, the application of MXenes in highly sensitive photodetection is far scarcely investigated. Here, we demonstrate high-quality Ti3C2Tx/GaAs Schottky junction by simply dripping Ti3C2Tx MXene solution on a pre-patterned GaAs substrate. Owing to the wide absorption of MXene and the good quality junction, the self-driven Ti3C2Tx/GaAs Schottky junction photodetector with an impressive performance is realized. The assembled photodetector exhibits a high sensitivity over a wide waveband with a good responsivity of ~1.46 A/W, a large specific detectivity of ~1.23 × 1013 Jones, and a high Ilight/Idark ratio of 5.6 × 105. Significantly, the photodetector is capable of sensing infrared light signal up to 980 nm which exceeds the absorption edge of GaAs (874 nm) due to the generation of hot electrons in Ti3C2Tx MXene film. Given the superior device performance along with a simple and facile fabrication method, the Ti3C2Tx/GaAs Schottky junction photodetector may find the great potential in high performance broadband, self-driven photodetection applications.