Large peak-to-valley ratio of negative-differential-conductance in graphene p-n junctions

TL;DR

This paper demonstrates that monolayer graphene p-n junctions exhibit a high peak-to-valley ratio of negative differential conductance at room temperature, due to interband tunneling and bandgap effects, with potential for electronic applications.

Contribution

It reveals the conditions under which large negative differential conductance occurs in graphene p-n junctions, highlighting the role of interband tunneling and symmetry breaking.

Findings

Peak-to-valley ratio can reach tens at room temperature.

Negative differential conductance depends on device parameters.

High interband tunneling is key to the observed behavior.

Abstract

We investigate the transport characteristics of monolayer graphene p-n junctions by means of the non-equilibrium Green's function technique. It is shown that thanks to the high interband tunneling of chiral fermions and to a finite bandgap opening when the inversion symmetry of graphene plane is broken, a strong negative-differential-conductance behavior with peak-to-valley ratio as large as a few tens can be achieved even at room temperature. The dependence of this behavior on the device parameters such as the Fermi energy, the barrier height, and the transition length is then discussed.