High-Efficiency\nSelf-Powered Broadband Photodetector\nBased on PtSe₂/MoSe₂ Heterojunction

Abstract

Platinum selenide (PtSe₂) is a new 2D transition\nmetal\ndichalcogenide with tunable bandgap, high carrier mobility, and air\nstability, which has hopeful applications in high-performance photodetectors\nand microelectronic devices. However, low response and large dark\ncurrent caused by the semimetal properties of PtSe₂ limit\nits applications. In this work, a PtSe₂/MoSe₂ heterojunction photodetector is constructed for high-performance\nbroadband self-powered photodetection. The device exhibits a rectification\nratio exceeding 10⁵, achieving an ultralow reverse current\nof 10^–12 A, and superior photovoltaic performance\nunder illumination. The heterojunction photodetector can respond to\na broadband spectrum from visible to near-infrared with an external\nquantum efficiency (EQE) of 64.2%, a photovoltaic responsivity of\n275 mA/W, a photovoltaic specific detectivity of 1.96 × 10¹¹ Jones, and a filling factor of 0.46. In addition, a significant\nspecific detectivity of 1.2 × 10¹³ Jones, a high responsivity\nof 9.02 × 10³ A/W, and an EQE of 2.1 × 10⁷% were obtained under forward bias (3 V). Moreover, the broadband\nimaging capability in both biasing and self-powered modes also proves\nthe application potential of the PtSe₂/MoSe₂ heterojunction photodetector. This work highlights the promising\npotential of 2D transition metal dichalcogenide for broadband, self-powered,\nand high-performance photodetection.