Non-linear resistivity and heat dissipation in monolayer graphene

TL;DR

This study investigates the nonlinear electrical conduction and heat dissipation mechanisms in monolayer graphene, revealing how self-heating and phonon interactions influence resistance behavior at low temperatures.

Contribution

It provides experimental insights into the nonlinear resistivity and heat dissipation processes in monolayer graphene, highlighting the role of sample length and interface phonons.

Findings

Differential resistance peaks near zero bias at low temperatures due to self-heating.

Heat dissipation mechanisms depend on sample length, involving optical phonons for longer samples.

Nonlinear conduction is influenced by energy dissipation processes at the graphene-silica interface.

Abstract

We have experimentally studied the nonlinear nature of electrical conduction in monolayer graphene devices on silica substrates. This nonlinearity manifests itself as a nonmonotonic dependence of the differential resistance on applied DC voltage bias across the sample. At temperatures below ~70K, the differential resistance exhibits a peak near zero bias that can be attributed to self-heating of the charge carriers. We show that the shape of this peak arises from a combination of different energy dissipation mechanisms of the carriers. The energy dissipation at higher carrier temperatures depends critically on the length of the sample. For samples longer than 10um the heat loss is shown to be determined by optical phonons at the silica-graphene interface.