Exploring new frontiers: graphene-embedded silicon waveguides for telecommunication photodetection

Our focus on silicon photonics addresses the challenge of NIR photodetection. We introduce a novel method embedding graphene (Gr) between crystalline (c-Si) and hydrogenated amorphous silicon (a-Si:H) to overcome it. This method enhances light-matter interaction, precisely confining the optical field where Gr is placed. We integrate the photodetector (PD) into a Silicon-On-Insulator waveguide, revealing a new photoconversion mechanism induced by traps at the Gr/a-Si:H interface. These traps release charge carriers into graphene under NIR light, boosting the generated current. In our PD within the a-Si:H/c-Si waveguide, Gr is positioned where field intensity peaks, maximizing interaction at 1.55 μm. Numerical simulations fine-tuned waveguide dimensions for optimized performance. Preliminary optical characterization shows promising responsivity evaluation of 0.22 A/W at 1550 nm wavelength under a reverse bias of –10 V applied to the PD. These findings signify a significant advancement in silicon photonics research.