Engineers develop technique to locate nanoscale ‘hot spots’ in electronic components to improve their longevity

When electronic devices like laptops or smartphones overheat, they are fundamentally suffering from a heat transfer problem at the nanoscale. Identifying the source of this problem can be a bit like trying to find a needle in a haystack.

“The building blocks of our modern electronics are transistors with nanoscale features. To understand which components are overheating, the first step is to get a detailed temperature map,” says Andrea Pickel, an assistant professor in the Department of Mechanical Engineering at the University of Rochester. “But for that, you need something with nanoscale resolution.”

Existing optical thermometry techniques are impractical because they have fundamental limitations in the spatial resolution they can achieve.

So Pickel and materials science PhD students Ziyang Ye and Benjamin Harrington have designed a new approach to overcome these limitations by building on the Nobel Prize in Chemistry super-resolution fluorescence optical microscopy techniques used in biological imaging.

In a new Scientific progressstudyThe researchers describe their process of mapping heat transfer using luminescent nanoparticles.

By applying highly doped nanoparticles to the surface of a device, the researchers were able to achieve very high-resolution thermometry at the nanoscale down to 10 millimeters away. That distance is extremely large in the world of super-resolution microscopy, Pickel says, and the biological imaging techniques they drew inspiration from typically work at less than a millimeter.

Pickel explains that while biological imaging techniques are a great source of inspiration, their application to electronics presents significant obstacles because they involve very different materials.

“Our requirements are very different from those of biologists because they’re studying things like cells and water-based materials,” she explains. “Often, they might have a liquid like water or oil between their objective and their sample. That’s great for biological imaging, but if you’re working with an electronic device, that’s the last thing you want.”

The paper presents the technique using an electrical heating structure that the team designed to produce steep temperature gradients, but Pickel says their method can be used by manufacturers to improve a wide range of electrical components. To further improve the process, the team hopes to reduce the laser power used and refine methods for applying layers of nanoparticles to devices.