Room-Temperature Near-Infrared and Self-Powered Photodetectors Based on Graphite/WTe } /Ge Mixed Van Der Waals Heterostructure

Herein, we report a graphite (Gr)/WTe _{\text{2}} /Ge mixed-dimensional van der Waals (vdWs) heterojunction-based Schottky photodetector (PD) for self-powered near-infrared detection. Notably, the fabricated device can respond to the wide spectrum of 400-2200 nm with the optimal wavelength around 1550 nm. In particular, it exhibited remarkable photovoltaic characteristics with a maximum responsivity of 2.3 A/W, a specific detectivity of 3.4 \times 10 ^{\text{10}} Jones, and a light \textit{I}_{\biosc{on}} / \textit{I}_{\biosc{off}} ratio of over 10 ^{\text{3}} with a fast response speed of 4.4/8.6 \mu s under 1550 nm. Moreover, a clear single-point image of "SCNU" in the self-driven mode can be obtained under 1550 nm illumination. The above results suggest that the constructed Gr/WTe _{\text{2}} /Ge PD shows great potential in the field of ultrafast near-infrared detection and high-resolution imaging.