Ultrahigh responsive negative photoconductivity photodetector based on multilayer graphene/InSe van der Waals heterostructure

Negative photoconductivity (NPC) exhibits great potential in the field of photodetection due to low power consumption and high response. Herein, the photodetectors based on InSe and multilayer graphene (MLG)/InSe van der Waals heterostructure are fabricated. The InSe photodetector shows a positive photoconductivity (PPC) behavior, while the MLG/InSe photodetector exhibits NPC behavior. The ultrahigh responsivity (1.88 × 105 A/W) is achieved for the NPC MLG/InSe photodetector, which is five orders of magnitude higher than that of the sole InSe photodetector based on PPC (6.97 A/W). The MLG/InSe photodetector also shows a high external quantum efficiency (6.41 × 107%) and a fast response time (22 ms). The proposed high-performance MLG/InSe heterostructure photodetector based on NPC for low-dimensional materials may extend applications in future optoelectronic devices.