Is it getting hot in here, or is it just your electronics?
Laptops, cellphones, and other electronic devices are hot – and we’re not just talking about tech trends. More transistors are being jammed into smaller surface areas within computer chips, and MIT engineers say this could result in explosive interactions between electrons and heat-carrying particles called phonons.
“When your computer is running, it generates heat, and you want this heat to dissipate, to be carried out by phonons,” said Bolin Liao, lead author of a recent paper published by MIT researchers in the journal Nature Communications.
“If phonons are scattered by electrons, they’re not as good as we thought they were in carrying heat out. This will create a problem that we have to solve as chips become smaller.”
In experiments, the MIT team used precisely timed laser pulses to measure the interactions between electrons and phonons in a very thin silicon wafer. As the concentration of electrons in the silicon increased, the more the electrons scattered the phonons and prevented them from transporting heat away.
Even though this has a hazardous impact on electronic devices, it could be beneficial for things like thermoelectric generators that convert heat directly into electrical energy. Scattering phonons could reduce heat leakage and improve performance for this application.
“Now we know this effect can be significant when the concentration of electrons is high,” said Liao. “We now have to think of how to engineer the electron-phonon interaction in more sophisticated ways to benefit both thermoelectric and microelectronic devices.”
