High-performance self-powered broadband photodetector based on a PtS₂/MoSe₂ vertical heterostructure

Broadband photodetectors that operate across the visible to infrared spectrum are vital for applications in environmental monitoring, biomedicine, remote sensing, imaging, and optical communications. However, most existing devices require external bias, which undermines energy efficiency and slows response due to depletion-region perturbations. Here, we demonstrate a self-powered PtS₂/MoSe₂ van der Waals heterostructure photodetector that leverages type-II band alignment to establish a built-in electric field, enabling efficient carrier separation without external bias. The device exhibits an ultralow dark current of ~10^-13 A and a broadband response spanning 405-1064 nm. Under 532 nm excitation with a 0 V bias, it achieves a responsivity of 0.22 A W^-1, a specific detectivity of 5.7 × 10⁹ Jones, and an external quantum efficiency of 50.4%. Moreover, the heterostructure delivers high-quality imaging across the visible-infrared regime. These results highlight the PtS₂/MoSe₂ heterostructure as a powerful platform for low-power, stable, and highly sensitive broadband photodetection, paving the way for advanced multispectral sensing and imaging technologies.