PbSe-Modified Graphene/Si Heterojunction for Self-Powered Broadband Detection with Dual-Light Modulation Effects

Self-powered broadband photodetectors hold significant promise for sensing, communications, and imaging applications. This work presents a high-performance, self-powered broadband photodetector based on an electrochemically synthesized PbSe cubic crystal-modified graphene/Si heterojunction. The device exhibits favorable photoelectric characteristics, achieving a detectivity D* of 3.59 × 10¹⁰ Jones at 1550 nm and 2.1 × 10⁹ Jones under room-temperature 600 K blackbody radiation. Innovatively, the integration of infrared-sensitive material modification with the highly tunable Fermi level of graphene enables effective decoupling between photon energy and Schottky barrier height within the graphene/Si junction. Experimental results confirm a novel dual-light modulation effect: photogenerated carriers induced by an infrared modulating light dynamically shift the graphene's Fermi level, thereby significantly modulating the photocurrent response generated by a signal light. This mechanism establishes a new pathway for the dynamic control of optoelectronic signals. Finally, the potential of this device for imaging applications is demonstrated.