Tuning the doping of epitaxial graphene on a conventional semiconductor via substrate surface reconstruction

TL;DR

This paper demonstrates how to control the doping type of epitaxial graphene on germanium by manipulating substrate surface reconstruction through thermal annealing, supported by experimental and theoretical analysis.

Contribution

It introduces a method to tune graphene doping via substrate surface reconstruction, combining microscopy, spectroscopy, and first-principles modeling.

Findings

Doping of graphene can be switched from p to n by substrate surface changes.

Surface reconstruction on Ge influences graphene's electronic properties.

Theoretical model aligns with experimental results.

Abstract

Combining scanning tunneling microscopy and angle-resolved photoemission spectroscopy, we demonstrate how to tune the doping of epitaxial graphene from p to n by exploiting the structural changes that occur spontaneously on the Ge surface upon thermal annealing. Furthermore, using first principle calculations we build a model that successfully reproduces the experimental observations. Since the ability to modify graphene electronic properties is of fundamental importance when it comes to applications, our results provide an important contribution towards the integration of graphene with conventional semiconductors.