Large-area 2D PtTe/silicon vertical-junction devices with ultrafast and high-sensitivity photodetection and photovoltaic enhancement by integrating water droplets.

2D PtTe2 layers, a relatively new class of 2D crystals, have unique band structure and remarkably high electrical conductivity promising for emergent opto-electronics. This intrinsic superiority can be further leveraged toward practical device applications by merging them with mature 3D semiconductors, which has remained largely unexplored. Herein, we explored 2D/3D heterojunction devices by directly growing large-area (>cm2) 2D PtTe2 layers on Si wafers using a low-temperature CVD method and unveiled their superior opto-electrical characteristics.