The invention belongs to the technical field of 
semiconductor photoelectric detection, and particularly relates to a tunneling photoelectric 
detector based on a Van der Waals 
heterojunction and a preparation method of the tunneling photoelectric 
detector. A 
metal type two-dimensional material is used as a carrier 
transport layer; an insulating type two-dimensional material is used as a 
barrier layer and a tunneling layer; and a 
semiconductor type two-dimensional material is used as a 
photoelectric conversion material. The device structure sequentially comprises a substrate (1), a 
metal type two-dimensional material layer (2), an insulating type two-dimensional material tunneling layer (3), a 
semiconductor type two-dimensional material light 
absorption layer (4) and a 
metal electrode (5) from bottom to top. When the device works, the insulating type two-dimensional material plays a role of the 
barrier layer in the dark, which improves the potential barrier to prevent 
electron transmission, and effectively reduces the 
dark current of the device; under 
light irradiation, bias 
voltage is applied to enable the insulating type two-dimensional material layer to generate a tunneling effect, a conduction step of 
photon-generated carriers is formed, a carrier multiplication effect is generated, and the 
photocurrent of the device is effectively improved. The device has the characteristicsof high response rate, high 
detection rate, high 
optical switch ratio, quick response and the like.