Current-voltage characteristics of graphene devices: interplay between Zener-Klein tunneling and defects

TL;DR

This study investigates the current-voltage behavior of graphene devices near the Dirac point, revealing a superlinear I-V relationship influenced by Zener-Klein tunneling and defect scattering, with experimental and theoretical insights.

Contribution

It provides a combined theoretical and experimental analysis of how Zener-Klein tunneling and defects affect graphene's I-V characteristics near the Dirac point.

Findings

I-V follows a power law with exponent 1<α≤1.5

Lower mobility correlates with higher α

Defects enhance visibility of Zener-Klein tunneling

Abstract

We report a theoretical/experimental study of current-voltage characteristics (I-V) of graphene devices near the Dirac point. The I-V can be described by a power law (I \propto V^\alpha, with 1< \alpha <= 1.5). The exponent is higher when the mobility is lower. This superlinear I-V is interpreted in terms of the interplay between Zener-Klein transport, that is tunneling between different energy bands, and defect scattering. Surprisingly, the Zener-Klein tunneling is made visible by the presence of defects.