Hot-carrier photocurrent effects at graphene-metal interfaces

TL;DR

This paper investigates the ultrafast photo-thermoelectric photocurrent at graphene-metal interfaces, revealing how photon energy, Fermi level, and polarization influence photocurrent generation, with implications for optoelectronic device design.

Contribution

It provides a unified experimental framework explaining photo-thermoelectric photocurrent generation at graphene-metal interfaces, considering multiple influencing factors.

Findings

Photocurrent depends on photon energy, Fermi energy, and light polarization.

A single photo-thermoelectric model explains all observed phenomena.

Ultrafast photoexcitation leads to elevated electron temperatures and photocurrent generation.

Abstract

Photoexcitation of graphene leads to an interesting sequence of phenomena, some of which can be exploited in optoelectronic devices based on graphene. In particular, the efficient and ultrafast generation of an electron distribution with an elevated electron temperature and the concomitant generation of a photo-thermoelectric voltage at symmetry-breaking interfaces is of interest for photosensing and light harvesting. Here, we experimentally study the generated photocurrent at the graphene-metal interface, focusing on the time-resolved photocurrent, the effects of photon energy, Fermi energy and light polarization. We show that a single framework based on photo-thermoelectric photocurrent generation explains all experimental results.