High-Efficiency Self-Powered Broadband Photodetector Based on PtSe₂/MoSe₂ Heterojunction

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Platinum selenide (PtSe2) is a new 2D transition metal dichalcogenide with tunable bandgap, high carrier mobility, and air stability, which has hopeful applications in high-performance photodetectors and microelectronic devices. However, low response and large dark current caused by the semimetal properties of PtSe2 limit its applications. In this work, a PtSe2/MoSe2 heterojunction photodetector is constructed for high-performance broadband self-powered photodetection. The device exhibits a rectification ratio exceeding 105, achieving an ultralow reverse current of 10–12 A, and superior photovoltaic performance under illumination. The heterojunction photodetector can respond to a broadband spectrum from visible to near-infrared with an external quantum efficiency (EQE) of 64.2%, a photovoltaic responsivity of 275 mA/W, a photovoltaic specific detectivity of 1.96 × 1011 Jones, and a filling factor of 0.46. In addition, a significant specific detectivity of 1.2 × 1013 Jones, a high responsivity of 9.02 × 103 A/W, and an EQE of 2.1 × 107% were obtained under forward bias (3 V). Moreover, the broadband imaging capability in both biasing and self-powered modes also proves the application potential of the PtSe2/MoSe2 heterojunction photodetector. This work highlights the promising potential of 2D transition metal dichalcogenide for broadband, self-powered, and high-performance photodetection.