A Study of Vertical Transport in Silicon-Graphene Junction*

In this report, we explore the important roles of single layer graphene in the vertical tunneling process as a tunneling barrier. Although being a semimetal in the lateral lattice plane, the graphene together with the vdW gap acts as a tunneling barrier, that is nearly transparent to vertically tunneling electrons, due to its atomic thickness and the transverse momenta mismatch between the injected electrons and the graphene band structure. This is accentuated using electron tunneling spectroscopy (ETS) showing a lack of features corresponding to the Dirac cone band structure. Meanwhile, the graphene acts as a lateral conductor through which the potential and charge distribution across the tunneling barrier can be tuned. These unique properties make graphene an excellent 2D atomic grid, transparent to charge carriers, and yet offer the control of the carrier flux via the electrical potential.