Enhanced Photoelectric Responsivity of Graphene/GaAs Photodetector Using Surface Plasmon Resonance Based on Ellipse Wall Grating-Nanowire Structure

High-efficiency integrated photodetectors can assist in future high-speed communication devices for achieving high responsivity characteristics. In this paper, we designed and optimized a graphene/GaAs heterojunction photodetector based on ellipse wall grating-nanowire (EWG-NW) structure. We evaluated the optical and electrical performance of the photodetector between 400 and 800 nm by COMSOL. Compared with graphene/GaAs heterojunction photodetector based on plain structure, our device exhibits enhanced responsivity performance within the visible spectrum at 0 bias voltage. The maximum photocurrent responsivity of 514 mA/W (increased by 56%) and detectivity of 1.16 x 1011 Jones (increased by 41%) are achieved at 725 nm. The mechanism of improvement originates from surface plasmon resonance-enhanced electromagnetic field excited by elliptical wall gratings and metal nanowires in graphene/GaAs heterostructures, thus significantly enhancing carrier separation and transfer. We also analyzed the influence of structural parameter on the absorptivity. The result indicates that the performance of our photodetector can be significantly improved by our design of the plasma structure, which provides a potential scheme for the application of plasma structure optoelectronic devices.

Automated summary

This paper presents the design and optimization of a graphene/GaAs heterojunction photodetector based on the ellipse wall grating-nanowire structure. The device exhibits enhanced responsivity characteristics within the visible spectrum, achieving high photocurrent responsivity and detectivity at zero bias voltage. The improvement is attributed to the surface plasmon resonance-enhanced electromagnetic field, which enhances carrier separation and transfer.