A while back we looked at wide bandgap materials like GaN when used for power devices, but, along with power comes heat and the need for it to be dissipated. GaN isn’t great for that; the old sapphire substrates were very bad, and newer (and more expensive) SiC substrates are better but not sufficient, according to researchers at UC Riverside.
Metal is often used as a heat sink, but its ability to do so in very thin films dissipates because the main “mobile” element is the electron. In graphene, however, the main dissipative component is the phonon – essentially, the ability to carry the crystal vibration efficiently, and this remains effective even for just a few layers.
So they built transistors with “quilts” of graphene on the actual transistor drains, connecting it to graphite heat sinks (although they say other heat sinks are possible too). These can be more effective because they insinuate themselves deep into the circuit without substantially disrupting the topology due to their use of “few-layer graphene” (FLG).
Of course, today, graphene is typically obtained by flaking graphite – something of an inexact science. They see graphene growth as a reality in the future, which would make the whole process a bit more deterministic.
You can find out more and get access to a paper published in Nature here…