Farewell to faulty electronics with defect detection tool

Engineers at the Australian National University (ANU) have developed a powerful new tool to help manufacturers spot defects or unwanted features in everyday technology — such as mobile phones, batteries and solar cells — more easily and much earlier in the fabrication process than current methods. Their work has been described in the journal Advanced Energy Materials.

Working with scientists from the National Renewable Energy Laboratory in the US, the ANU researchers discovered that the light emitted from various semiconductor materials — including silicon, perovskites and many thin films — had some very distinct qualities. By capturing this light on camera, the optical images can be used to gather important information about how the material works.

Dr Hieu Nguyen, lead author on the study, explained that the team’s invention works by capturing high-resolution images of semiconductor materials, including many potential defects, within seconds. He said, “It’s not just several times faster than techniques currently being used — it’s tens of thousands of times faster.

“Now we know much more about the property of the light — and, just from the image, we can extract different information with incredible depth.”

Dr Nguyen said his team demonstrated their method by capturing images of the optical bandgap, one of the first pieces of information researchers need to know about a material. This bandgap determines many properties of semiconductors, including the ability to absorb light and conduct electricity.

“We tested this invention extensively on various state-of-the-art perovskite solar cells made here at ANU and independently confirmed the results with many other low-speed or low-resolution techniques. They matched perfectly,” he said.

“The beautiful part of this research is that we used ordinary tools that are commercially available, and converted them into something extraordinary.”

Co-author Boyi Chen, also from ANU, said he was thrilled by the results of the research. “Before this invention, it took an entire week to get a high-quality bandgap image on a device,” he said. “Now, with our invention, it takes just a few seconds to get an image with the same quality.

“This invention will help to produce more robust mobile phones, solar cells, sensors and other optical devices as it can spot defects very early in the fabrication process.”

According to Dr Nguyen, the invention will open the door to a new generation of ultrahigh-resolution, precise characterisation and defect-detection tools for both research and industry sectors. The team is currently refining the tool so that it can be commercialised.

Image caption: Dr Hieu Nguyen, ANU Research School of Electrical, Energy and Materials Engineering.

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