High-performance MoS₂ Homojunction Photodiode Enabled by Facile Van der Waals Contacts with 2D Perovskite

p-n junction, as an important part of modern electronics and integrated circuits, is the basis of various functional devices. Compared with heterojunctions, 2D p-n homojunctions preclude interface problems and have greater potential in ultra-sensitive photodetection. Here, through simple van der Waals contacts with a 2D perovskite layer, it is realized efficient p-type doping of MoS2 and constructed a high-performance photodiode based on MoS2 homogeneous p-n junction. The dark current is as low as 10(-12) A, with an ideality factor of 1.3. Under illumination, the open circuit voltage of the device can reach up to 0.7 V. In addition, under zero bias, the device exhibits a high responsivity of 529 mA W-1 and a fast response time of 105/109 mu s. This work not only provides a facile and stable method to construct the MoS2 p-n homojunction but also opens up possibilities for new-type 2D-based optoelectronic devices and technologies.