Observation of Tunneling Current in Semiconducting Graphene p-n Junctions

TL;DR

This paper reports the observation of tunneling and rectification in bilayer graphene p-n junctions, where an electric field induces a band gap and enables tunneling currents, revealing density of states features.

Contribution

It demonstrates electric field-induced band gap and tunneling behavior in bilayer graphene p-n junctions, a novel approach for 2D semiconductor device control.

Findings

Tunneling current exhibits a differential resistance peak at forward bias.

Electric field modulates the density of states in bilayer graphene.

Carrier charge tuning via electric field is analogous to impurity doping in 3D semiconductors.

Abstract

We demonstrate a tunneling and rectification behavior in bilayer graphene. A stepped dielectric top gate creates a spatially modulated electric field, which opens the band gap in the graphene and produces an insulating region at the p-n interface. A current-voltage relationship exhibiting differential resistance peak at forward bias stems from the tunneling current through the insulating region at the p-n interface. The tunneling current reflects singularities in the density of states modified by the electric field. This work suggests that the effect of carrier charge tuning by external electric field in 2D semiconductors is analogously to that by impurity doping in 3D semiconductors.