A High-Speed Photodetector Fabricated with Tungsten-Doped MoS2 by Ion Implantation

Molybdenum disulfide (MoS2) is a promising 2D semiconductor material for its unique characteristics such as tunable bandgap, high electrical conductivity, and strong light-matter interaction. Presently, many efforts have been made to modulate its properties, such as surface engineering, strain introduction, doping, and so on. Recently, it has been proved that substitutional metal doping is an effective approach to tune the energy bandgap of the aimed material and improve the performance of the device. Conventional metal doping methods will inevitably introduce impurities or defects and cannot control doping regions. Ion implantation is widely used in traditional semiconductor modification processes due to its high efficiency, controllability, and homogeneity. But it is rarely applied to 2D materials because of the damage caused during the implantation process. Here, the SiO2 substrate is implanted by tungsten ion implantation and then the tungsten doping of MoS2 is successfully achieved by chemical vapor deposition (CVD) growth process, while avoiding direct implantation damage to it. The W-doped MoS2 photodetectors show a high-speed response with a rise/fall time of 210 ms/160 ms. This work provides a novel doping strategy for metal doping of 2D materials and opens a new avenue to modify 2D materials properties.