Figure 3. Raman and thermal imaging of a bare epitaxial graphene device.

(a) Raman image of 2D-mode peak position before self-heating. Arrow highlights false color overlay of crack in (c). (b) Measured temperature distribution while dissipating 16 mW of power. This is not the graphene temperature but the volumetric average over the sampled volume of the IR measurement (See Supporting Information). (c) Raman image of 2D-mode intensity after failure where a crack is observed near the middle of the device. (d) Overlay of (b,c) showing that the crack is co-located with regions of most severe heating. The grounded electrode is on the right-hand side.