Graphene for more efficient heat transfer in electronic devices

US researchers claim nanostructured patterns with a graphene layer can dissipate heat particles more efficiently

Researchers at Rice University in Texas have found that bumpy surfaces with graphene between would help dissipate heat in next-generation microelectronic devices.

Heat sinks are used to carry heat away from electronic devices. The theoretical studies show that enhancing the interface between gallium nitride semiconductors and diamond heat sinks would allow phonons – quasiparticles of sound that also carry heat – to disperse more efficiently.

Rice computer models replaced the flat interface between the materials with a nanostructured pattern and added a layer of graphene, the atom-thick form of carbon, as a way to improve heat transfer. No matter the size, electronic devices need to disperse the heat they produce.

Rouzbeh Shahsavari, materials scientist at the university, said: “With the current trend of constant increases in power and device miniaturisation, efficient heat management has become a serious issue for reliability and performance. Often, the individual materials in hybrid nano and microelectronic devices function well but the interface of different materials is the bottleneck for heat diffusion.

“With current and emerging advancements in nanofabrication like nanolithography, it is now possible to go beyond the conventional planer interfaces and create strategically patterned interfaces coated with nanomaterials to significantly boost heat transport. Our strategy is amenable to several other hybrid materials and provides novel insights to overcome the thermal boundary resistance bottleneck.”

The researchers simulated 48 distinct grid patterns with square or round graphene pillars and tuned them to match phonon vibration frequencies between the materials. Sinking a dense pattern of small squares into the diamond showed a dramatic decrease in thermal boundary resistance of up to 80%. A layer of graphene between the materials further reduced resistance by 33%.

Gallium nitride has become a strong candidate for use in high-power, high-temperature applications like uninterruptible power supplies, motors, solar converters and hybrid vehicles, according to the researchers. Diamond is an excellent heat sink, but its atomic interface with gallium nitride is hard for phonons to traverse. Fine-tuning the pillar length, size, shape, hierarchy, density and order will be important.

The study appeared in the American Chemical Society journal ACS Applied Materials and Interfaces.