Two-dimensional (2D) heterostructure with atomically sharp interface holds promise for future electronics and optoelectronics because of their multi-functionalities. Here we demonstrate gatetunable rectifying behavior and self-powered photovoltaic characteristics of novel p-GeSe/n-MoSe2 van der waal heterojunction (vdW HJ). A substantial increase in rectifcation behavior was observed when the devices were subjected to gate bias. The highest rectifcation of~ 1 × 104  was obtained at Vg = − 40V. Remarkable rectifcation behavior of the p-n diode is solely attributed to the sharp interface between metal and GeSe/MoSe2. The device exhibits a high photoresponse towards NIR (850 nm). A high photoresponsivity of 465 mAW−1, an excellent EQE of 670%, a fast rise time of 180 ms, and a decay time of 360 ms were obtained. Furthermore, the diode exhibits detectivity (D) of 7.3 × 109
 Jones, the normalized photocurrent to the dark current ratio (NPDR) of 1.9× 1010W−1, and the noise equivalent power (NEP) of 1.22× 10–13WHz−1/2. The strong light-matter interaction stipulates that the GeSe/MoSe2 diode may open new realms in multi-functional electronics and optoelectronics applications.