Electron beam radiation has long been used in a variety of fields, including electron microscopy and lithography. A recent study, however, has revealed that it can also be used to repair nanostructures. This unexpected discovery has far-reaching ramifications for nanotechnology and materials research.
Researchers at the University of Minnesota Twin Cities discovered in a startling new study that electron beam radiation, which they previously assumed destroyed crystals, can help mend defects in these nanostructures.
The remarkable discovery opens up a new avenue for the creation of more precise crystal nanostructures, a process important to enhancing the efficiency and cost-effectiveness of materials utilized in almost all electrical devices we use every day.
For a long time, researchers studying nanostructures assumed that when we exposed the crystals to electron beam radiation to study them, they would degrade. What we showed in this study is that when we took a crystal of titanium dioxide and irradiated it with an electron beam, the naturally occurring narrow cracks actually filled in and healed themselves.
Andre Mkhoyan
“For a long time, researchers studying nanostructures assumed that when we exposed the crystals to electron beam radiation to study them, they would degrade,” said Andre Mkhoyan, a chemical engineering and materials science professor at the University of Minnesota and the study’s principal researcher. “What we showed in this study is that when we took a crystal of titanium dioxide and irradiated it with an electron beam, the naturally occurring narrow cracks actually filled in and healed themselves.”
The discovery was made by accident while utilizing the University of Minnesota’s cutting-edge electron microscope to investigate the crystals for a completely different purpose.
“I was studying the cracks in the crystals under the electron microscope, and these cracks kept filling in,” said Silu Guo, a Ph.D. student in chemical engineering and materials science at the University of Minnesota. “This was unexpected, and our team realized that maybe there was something even bigger that we should be studying.”
In the self-healing process, several atoms of the crystal moved together in tandem and met in the middle and formed a sort of bridge that filled the crack. For the first time, the researchers showed that the electron beams could be used constructively to engineer novel nanostructures atom-by-atom.
“Whether it’s atomically sharp cracks or other types of defects in a crystal, I believe it’s inherent in the materials we’ve grown, but it’s truly astonishing to see how Professor Mkhoyan’s group can mend these cracks using an electron beam,” said University of Minnesota Chemical Engineering and Materials Science Professor Bharat Jalan, a collaborator on the study.
The researchers claim the next step is to include new factors, such as modifying the electron beam settings or the temperature of the crystal, in order to improve or accelerate the process.
“First we discovered, now we want to find more ways to engineer the process,” Mkhoyan was quoted as saying.
