Highly polarization-sensitive, broadband, low dark current, high responsivity graphene-based photodetector utilizing a metal nano-grating at telecommunication wavelengths

Recent advances in graphene-based photodetectors have demonstrated the feasibility of utilizing graphene as a fantastic material for the development of future high-performance photodetectors. In this paper, a high-performance graphene-based photodetector is proposed with plasmonic structure by employing a single graphene layer, periodic metal nano-grating, and Si/SiO2 substrate. The plasmonic coupling phenomena between graphene and the metal nano-grating can cause absorption enhancement in this structure. The proposed structure has almost perfect absorption at the telecommunication wavelength (1.55 mu m), and its optical response shows a polarization-sensitive characteristic in the spectral range from 1 mu m to 2.1 mu m. Moreover, the electrical characterization and the dynamic response of this structure are obtained. Based on simulation results, the proposed structure under 0.5 mW incident optical power and at a wavelength of 1.55 mu m exhibits a low dark current on the order of about 0.001 mA, maximum photocurrent of 0.81 mA, and responsivity of 1650 mA/Wat a bias voltage of 3 V. Also, the rise time of the dynamic response is determined to be about 87 ps, and the 3 dB bandwidth of the frequency response is obtained to be about 4 GHz. (C) 2021 Optical Society of America

Automated summary

The study introduces a high-performance graphene-based photodetector structure capable of enhancing light absorption within a specific wavelength range, featuring low dark current, high responsivity, and fast dynamic response.