Scientists at the University of Minnesota Twin Cities have demonstrated that the electron beam radiation previously believed to degrade crystals can in fact repair cracks in such nanostructures. It is hoped that the breakthrough could offer a new approach to developing more perfect crystal nanostructures, a process critical to improving the efficiency and cost-effectiveness of materials common in nearly all electronic devices used today.
Researchers have long thought that when the crystals were put under electron beam radiation they would degrade, but here they found that when a crystal of titanium dioxide (TiO2) was irradiated with an electron beam, the naturally occurring narrow cracks filled in and managed to heal themselves. The discovery was found by accident when the team were using scanning transmission electron microscopy (STEM) to examine the structural and plasmonic properties of these nanoscale cracks and the cracks kept closing on them.
As reported in the journal Nature Communications [Guo et al. Nat. Commun. (2023) DOI: 10.1038/s41467-023-41781-x], instead of electron beam radiation damaging and degrading crystalline materials, they observed the opposite, a constructive aspect of the radiation. In the self-healing process, several atoms of the crystal combined in tandem with increasing electron doses and came together in the middle to form a kind of bridge that worked to fill the crack.
This is the first time that the electron beams have been employed in a constructive way to engineer novel nanostructures on an atom-by-atom basis. Regardless of whether it is atomically sharp cracks or another type of defect in a crystal, it seems to be inherent in the materials that were grown. The use of electron beam exposure during the growth of crystalline thin film for a variety of technologically important materials could therefore help to significantly improve the film quality.
As lead researcher Andre Mkhoyan told Materials Today, “This discovery will force researchers to re-evaluate and re-examine their view about the effects of electron beam radiation. There is a new opportunity to use constructive force of electron beam radiation.”
The team now plan to find further ways to engineer the process and to introduce new factors, such as altering the conditions of the electron beam or the temperature of crystal to identify how to improve or speed up the process. In addition, they are hoping to investigate different parameters of the electron beam and crystals to make this radiolysis-based process more efficient and practical.
“This discovery will force researchers to re-evaluate and re-examine their view about the effects of electron beam radiation. There is a new opportunity to use constructive force of electron beam radiation.”Andre Mkhoyan
In the self-healing process, several atoms of the crystal combine to form a bridge to fill the crack