Tunable GaTe-MoS2 van der Waals p-n Junctions with Novel Optoelectronic Performance

P-n junctions based on vertically stacked van der Waals (vdW) materials have attracted a great deal of attention and may open up unforeseen opportunities in electronics and optoelectronics. However, due to the lack of intrinsic p-type vdW materials, most previous studies generally adopted electrical gating, special electrode contacts, or chemical doping methods to realize p-n vdW junctions. GaTe is an intrinsic p-type vdW material with a relatively high charge density, and it has a direct band gap that is independent of thickness. Here, we report the construction of ultrathin and tunable p-GaTe/n-MoS2 vdW heterostructure with high photovoltaic and photo-detecting performance. The rectification ratio, external quantum efficiency, and photoresponsivity are as high as 4 x 10(5), 61.68%, and 21.83 AW(-1), respectively. In particular, the detectivity is up to 8.4 x 10(13) Jones, which is even higher than commercial Si, InGaAs photodetectors. This study demonstrates the promising potential of p-GaTe/n-MoS2 heterostructures for next-generation electronic and optoelectronic devices.