Facile construction of MXene/Ge van der Waals Schottky junction with Al2O3 interfacial layer for high performance photodetection

MXene/bulk semiconductor vdW Schottky junctions are considered to be a hopeful construction strategy for photodetection applications. However, the existence of interfacial states is an obstacle for their actualization. Herein, we developed a kind of Ti3C2Tx/Ge vdW Schottky junction photodetector with Al2O3 interfacial layer through a facile drop of Ti3C2Tx MXene solution on the well-defined Al2O3/Ge substrate. The Al2O3 interfacial layer brings a positive impact on the suppression of dark current and the improvement of light current. Actually, the device shows remarkable photodetection characteristics at 1550 nm with self-powered mode in term of a high responsivity of 665 mA/W, a large specific detectivity of 1.24 × 1013 Jones, a fast response speed of 73.5/81.5 μs. The device also exhibits a broadband response spectrum from 405 to 1550 nm. These fascinating performances and the simple device preparation make the Ti3C2Tx/Al2O3/Ge vdW Schottky junction be promising for the low cost but high performance optoelectronic devices.