One-Pot Synthesized Mixed-Dimensional Graphene for Photodetectors in Near-Infrared Image Sensors and Logic Circuits

Abstract The advancement of heterostructures in two-dimensional (2D) materials plays a pivotal role in enhancing their optoelectronic capabilities. Nevertheless, existing heterostructures encounter limitations concerning light absorption efficiency and band alignment, impeding the generation and transportation of photo-generated charge carriers. To overcome these challenges, we have pioneered the development of a self-powered photodetector operating in the near-infrared (NIR) spectra. This innovative photodetector is built upon nitrogen-doped graphene quantum dots (N-GQDs), three-dimensional (3D) graphene, and germanium (Ge) Schottky junctions. By leveraging the remarkable light absorption capabilities of N-GQDs and 3D-graphene, combined with precisely aligned heterostructure band alignment, as-fabricated device manifests a robust built-in electric field. Consequently, it facilitates efficient generation and separation of photo-generated charge carriers, thereby significantly amplifying overall optoelectronic performance. The as-fabricated photodetectors exhibit exceptional responsivity (2.3 × 103 A/W) and specific detectivity (6.2 × 1014 Jones) when illuminated at 2200 nm. Extensive studies validate the outstanding reproducibility, long-term stability, and microsecond-level rise/fall times of the proposed photodetectors. Particularly noteworthy is their remarkable image sensing capability, enabling the capture of high-resolution images in the NIR range. Furthermore, we have successfully demonstrated the integration of as-fabricated photodetector into optically controlled digital logic circuits. This groundbreaking research paves the way for designing and fabricating high-performance 3D heterostructures, opening up exciting possibilities for diverse optoelectronic applications.