Van der Waals heterostructures have also been demonstrated to exhibit remarkable performance in optoelectronic devices. Here, a self-driven photodetector based on GaSe/MoSe2 field-effect transistor (FET) was designed and fabricated. The built-in electric field in the type-II band alignment can exhibit excellent response and serve as an equivalent of a bias voltage. Moreover, the detector can achieve a broad bandwidth spanning from 520 nm to 850 nm, with peak responsivity observed at 785 nm. The heterostructure device produced responsivity of 0.47 A/W at a power density of 80 mW/cm2, an external quantum efficiency of 74.4%, a specific detectivity of 9.65×109 Jones, and a fast photoresponse speed (24.6 ms). In addition, the photodetector presents a well-defined rectification ratio of 95.6, which is comparable to that of a conventional diode. These results indicate that GaSe/MoSe2 photodetectors can provide high performance for future optoelectronic devices.

The increasing demand for broadband and self-powered optoelectronic devices has stimulated the development of two-dimensional (2D) material-based photodetectors. Here, we construct a self-powered photodetector based on a MoSe₂/SnS₂ van der Waals (vdW) heterostructure. The unique combination of MoSe₂ and SnS₂ provides complementary light absorption and a type-II band alignment, which generates an interfacial built-in electric field to facilitate photogenerated carrier separation and transport, enabling efficient self-powered operation without external bias. The device exhibits a broad spectral photoresponse from ultraviolet (UV) to infrared (IR) wavelengths (350–1050 nm). Under zero bias, the photodetector achieves a responsivity of 0.6 mA/W and a rapid response time of 5.8/6.1 ms (rise/fall) under 405 nm illumination, demonstrating effective self-driven photoresponse. With an applied reverse bias of −2 V, the device further reaches a responsivity of 161 mA/W and a detectivity of 8.6 × 10¹⁰ Jones under 405 nm illumination. In addition, the device exhibits a low dark current of 5 pA and a high on/off ratio of 1180. These results demonstrate the potential of the MoSe₂/SnS₂ vdW heterostructure for broadband and self-powered optoelectronic applications.