Suppression of electron scattering resonances in graphene by quantum dots

TL;DR

This study investigates how quantum dot nanopatterning can suppress electron scattering resonances in graphene, revealing a method to tune its optoelectronic properties by inducing structural rehybridization.

Contribution

It demonstrates that quantum dot superlattices can eliminate scattering resonances in graphene through induced buckling and rehybridization, offering a new approach for property control.

Findings

Quantum dot superlattices eliminate scattering resonances in graphene.

Charge transfer influences the energy of scattering resonances.

Nanopatterning induces buckling and rehybridization in graphene.

Abstract

Transmission of low-energetic electrons through two-dimensional materials leads to unique scattering resonances. These resonances contribute to photoemission from occupied bands where they appear as strongly dispersive features of suppressed photoelectron intensity. Using angle-resolved photoemission we have systematically studied scattering resonances in epitaxial graphene grown on the chemically differing substrates Ir(111), Bi/Ir, Ni(111) as well as in graphene/Ir(111) nanopatterned with a superlattice of uniform Ir quantum dots. While the strength of the chemical interaction with the substrate has almost no effect on the dispersion of the scattering resonances, their energy can be controlled by the magnitude of charge transfer from/to graphene. At the same time, a superlattice of small quantum dots deposited on graphene eliminates the resonances completely. We ascribe this effect to a nanodot-induced buckling of graphene and its local rehybridization from sp$^{2}$ to sp$^{3}$ towards a three-dimensional structure. Our results suggest nanopatterning as a prospective tool for tuning optoelectronic properties of two-dimensional materials with graphene-like structure.