Low Schottky barrier height and transport mechanism in Gold-Graphene-Silicon (001) heterojunctions

The interface resistance at metal/semiconductor junction has been a key issue for decades. The control of this resistance is dependent on the possibility to tune the Schottky barrier height. However, Fermi level pinning in these systems forbids a total control over interface resistance. The introduction of 2D crystals between semiconductor surfaces and metals may be an interesting route towards this goal. In this letter, we study the influence on the Schottky barrier height of the introduction of a graphene monolayer between metal and silicon. We used X-ray Photoemission Spectroscopy to rule out the presence of oxide at the interface, the absence of pinning of the Fermi level and the strong reduction of the Schottky barrier height. We then realized a multiscale transport analysis to determine the transport mechanism. The consistency in the measured barrier height at different scales confirms the good quality of our junctions and the role of graphene in the drastic reduction of the barrier height.