Photothermoelectric and Photoelectric Contributions to Light Detection in Metal–Graphene–Metal Photodetectors

TLDR

Graphene’s high mobility, Fermi velocity, and constant light absorption across the visible to far‑infrared spectrum make it ideal for high‑speed, ultrabroadband photodetectors, though the exact photodetection mechanism remains debated. The study aims to determine how wavelength and polarization affect metal–graphene–metal photodetectors. The authors perform wavelength‑ and polarization‑dependent measurements on metal–graphene–metal devices to dissect photothermoelectric and photoelectric contributions. They quantify and control the relative contributions of photothermoelectric and photoelectric effects, enabling more efficient, ultrafast photodetector designs.

Abstract

Graphene’s high mobility and Fermi velocity, combined with its constant light absorption in the visible to far-infrared range, make it an ideal material to fabricate high-speed and ultrabroadband photodetectors. However, the precise mechanism of photodetection is still debated. Here, we report wavelength and polarization-dependent measurements of metal–graphene–metal photodetectors. This allows us to quantify and control the relative contributions of both photothermo- and photoelectric effects, both adding to the overall photoresponse. This paves the way for a more efficient photodetector design for ultrafast operating speeds.