Dynamics of Li deposition on epitaxial graphene/Ru(0001) islands

TL;DR

This study investigates how lithium metal deposits and diffuses on epitaxial graphene islands on Ru(0001), revealing differences in work function changes and intercalation behavior through in situ microscopy techniques.

Contribution

It provides new insights into lithium intercalation and diffusion on graphene/Ru(0001), combining real-time microscopy with work function measurements.

Findings

Li decreases work function more on Ru(0001) than on graphene islands

Li intercalates below graphene, affecting electronic properties

Diffusion of Li out of graphene islands was monitored in real-time

Abstract

Li metal has been deposited on the surface of a Ru(0001) single crystal containing patches of monolayer-thick epitaxial graphene islands. The use of low-energy electron microscopy and diffraction allowed us to {\em in situ} monitor the process by measuring the local work function as well as to study the system in real and reciprocal space, comparing the changes taking place on the graphene with those on the bare Ru(0001) surface. It is found that Li deposition decreases the work function of the graphene islands but to a much smaller degree than of the Ru(0001) surface, as corresponds to its intercalation below the graphene overlayer. Finally, the diffusion process of Li out of the graphene islands has been monitored by photoelectron microscopy using a visible-light laser.