Imagine trying to spot a single crooked line hidden in a wall made of millions of perfectly aligned bricks. That is essentially what scientists have struggled to do when looking for tiny defects inside the crystals that make up LED lights. But now, researchers in the United Kingdom have found a better way to do exactly that.
LEDs are everywhere — from the light bulbs in your home to the screens of mobile phones and large digital displays. These devices work by converting electrical energy into light, and they are made from a material called gallium nitride, a crystalline substance grown in labs. Sometimes, during the crystal growth process, small imperfections called dislocations form. Think of them like wrinkles in an otherwise smooth crystal surface. These imperfections can make LEDs less efficient, wasting energy as heat instead of light.
For years, scientists have used a powerful but limited technique called Transmission Electron Microscopy to find these defects. The problem? It only lets them examine tiny, razor-thin slices of material, making it hard to get the full picture.
In a new study published in the journal Acta Materialia, researchers from the University of Liverpool and the University of Strathclyde took a different approach. They used a scanning electron microscopy technique called Electron Backscatter Diffraction, or EBSD for short, which can examine much larger areas of crystal more easily. By combining EBSD with a calculation method developed by University of Liverpool geoscientist John Wheeler, the team was able to spot individual dislocations for the first time — and even tell them apart by type, including edge, screw, and mixed dislocations.
Professor John Wheeler, who holds the George Herdman Chair of Geology at the University of Liverpool and co-authored the study, said being able to identify individual defects this way is a major step forward. The technique allows researchers to study crystal flaws across much larger areas than before, building a clearer understanding of how crystals grow and change. That knowledge could eventually help engineers design LEDs that convert more electricity into light and less into wasted heat.
The researchers believe this is the first time such detailed imaging has been achieved using EBSD in gallium nitride. The method could also be applied to other crystalline materials — both natural, like minerals found in rocks, and human-made — where similar defects play a role in determining strength, flexibility, and other properties.