Integration of PbS Quantum Dots with 3D-Graphene for Self-powered Broadband Photodetectors in Image Sensors

High-performance broadband photodetectors (PDs) are crucial in various military and civilian applications. However, conventional near-infrared (NIR) PDs still face several inevitable self-limitations such as a finite light absorption range for silicon (Si) and large area array issues for InGaAs. In response to these challenges, this work proposes a high-performance and uncooled NIR PD with wide-band response and long-term stability, which is integrated by the PbS quantum dots (QDs)/three-dimensional graphene (3D-graphene)/Si heterojunction. The incorporation of nanostructures (3D-graphene) and interface engineering (PbS QDs) on Si efficiently modulates carrier transport, optimizes light absorption, and enhances photovoltaic conversion efficiency. The detection range of the as-proposed Si-based PD can be extended to 2200 nm. And even at this wavelength, the device exhibits high detectivity (6.8 × 10¹⁰ Jones) and high responsivity (5.2 × 10⁴ mA/W). Furthermore, the device demonstrates satisfactory reproducibility and long-term stability, holding significant promise in optical logic gate circuits and infrared imaging applications. This research unlocks the full potential of Si in NIR detection and underscores its considerable potential in the development of next-generation NIR imaging and integrated circuits.