Soft Carrier Multiplications by Hot Electrons in Graphene

TL;DR

This paper demonstrates that impact ionization-induced carrier multiplication occurs at low electric fields in graphene, with a quadratic dependence on the field and sensitivity to temperature and carrier concentration.

Contribution

It introduces a Boltzmann formalism analysis showing impact ionization effects in graphene without a threshold, differing from conventional semiconductors.

Findings

Carrier multiplication occurs at low electric fields in graphene.

The effect is quadratic in the electric field.

Current increases with electronic temperature but decreases with carrier concentration.

Abstract

By using Boltzmann formalism, we show that carrier multiplication by impact ionization can take place at relatively low electric fields during electronic transport in graphene. Because of the absence of energy gap, this effect is not characterized by a field threshold unlike in conventional semiconductors, but is a quadratic function of the electric field. We also show that the resulting current is an increasing function of the electronic temperature, but decreases with increasing carrier concentration.