Imaging, simulation, and electrostatic control of power dissipation in graphene devices

TL;DR

This study uses infrared thermal microscopy and simulations to visualize and understand hot spot formation and power dissipation in graphene transistors, revealing how bias and material properties influence energy distribution.

Contribution

It introduces a non-invasive thermal imaging method combined with modeling to analyze energy dissipation and hot spot dynamics in graphene devices.

Findings

Hot spots align with minimum charge density locations.

Hot spot position can be controlled by bias adjustments.

Shape of hot spots reflects the density of states in graphene.

Abstract

We directly image hot spot formation in functioning mono- and bilayer graphene field effect transistors (GFETs) using infrared thermal microscopy. Correlating with an electrical-thermal transport model provides insight into carrier distributions, fields, and GFET power dissipation. The hot spot corresponds to the location of minimum charge density along the GFET; by changing the applied bias this can be shifted between electrodes or held in the middle of the channel in ambipolar transport. Interestingly, the hot spot shape bears the imprint of the density of states in mono- vs. bilayer graphene. More broadly, we find that thermal imaging combined with self-consistent simulation provides a non-invasive approach for more deeply examining transport and energy dissipation in nanoscale devices.