Charge and energy transfer are fundamental processes in van der Waals heterostructures (vdWHs), and controlling the transfer pathway is crucial for applications spanning from photodetection to photoluminescence. However, deterministic modulation of energy transfer (ET) and charge transfer (CT) is limited by static band alignments and physical barrier thicknesses. Here, we integrate an optical microcavity with two-dimensional (2D) heterostructures, leveraging the cavity resonance as a switch to convert the dominant mechanism from energy transfer to charge transfer, an unexpected transition that is tunable via laser parameters and cavity geometry. We reveal that the cavity-modified local electromagnetic environment thermodynamically stabilizes the CT pathways via dipole-selective coupling. Furthermore, cavity-mediated exciton-photon hybridization generates intermediate states that reconstruct the non-equilibrium relaxation landscape, while the cavity-enhanced local field induces photon-assisted tunneling to overcome intrinsic barrier limitations. Our work provides unprecedented flexibility for manipulating carrier dynamics in tunable optoelectronics, opening new avenues for ultrafast photodetectors, low-power photovoltaics, tunable switches, and various interdisciplinary applications.

As one of the most promising materials for two-dimensional transition metal chalcogenides (2D TMDs), molybdenum diselenide (MoSe₂) has great potential in photodetectors due to its excellent properties like tunable bandgap, high carrier mobility, and excellent air stability. Although 2D MoSe₂-based photodetectors have been reported to exhibit admired performance, the large-area 2D MoSe₂ layers are difficult to be achieved via conventional synthesis methods, which severely impedes its future applications. Here, we present the controllable growth of large-area 2D MoSe₂ layers over 3.5-inch with excellent homogeneity by a simple post-selenization route. Further, a high-quality n-MoSe₂/p-Si van der Waals (vdW) heterojunction device is in-situ fabricated by directly growing 2D n-MoSe₂ layers on the patterned p-Si substrate, which shows a self-driven broadband photoresponse ranging from ultraviolet to mid-wave infrared with an impressive responsivity of 720.5 mA·W⁻¹, a high specific detectivity of 10¹³ Jones, and a fast response time to follow nanosecond pulsed optical signal. In addition, thanks to the inch-level 2D MoSe₂ layers, a 4 × 4 integrated heterojunction device array is achieved, which has demonstrated good uniformity and satisfying imaging capability. The large-area 2D MoSe₂ layer and its heterojunction device array have great promise for high-performance photodetection and imaging applications in integrated optoelectronic systems.