Materials scientists at the University of Minnesota have discovered a novel method to create and precisely control microscopic “flaws” within ultra-thin materials. These internal imperfections, formally known as extended defects, offer a promising pathway to endow next-generation nanomaterials with unprecedented properties, potentially sparking significant advancements in nanotechnology.
Understanding Extended Defects
Extended defects are disruptions in a material’s crystal structure that extend across a relatively large area – unlike point defects which affect single atoms. Think of a pristine crystal lattice like a perfectly arranged grid of building blocks; an extended defect is like a deliberate, carefully placed break in that grid. The unique aspect of these defects is that they occupy a small volume while influencing the properties of the surrounding material significantly.
Achieving Unprecedented Control
The research, published in Nature Communications, demonstrated the ability to engineer regions within the material with densities of these extended defects up to 1,000 times greater than in areas without patterning. This level of control is crucial because it allows researchers to tailor materials’ properties in specific zones.
“These extended defects are exciting because they span the entire material but occupy a very small volume,” explains Andre Mkhoyan, a professor in the University of Minnesota’s Department of Chemical Engineering and Materials Science and senior author of the study. “By carefully controlling these tiny features, we can leverage the properties of both the defect and the surrounding material.”
The Technique: Patterned Defect Creation
The team’s breakthrough lies in a new approach to material design. They found that by creating tiny, defect-inducing patterns on the surface before growing the thin film, they could precisely control the density and type of extended defects.
“We figured out a new way to design materials by making tiny, defect-inducing patterns on the substrate surface before growing thin film on it,” said Supriya Ghosh, a graduate student in the Mkhoyan Lab and first author on the paper.
This technique allows for the creation of materials with drastically different properties in different sections. By concentrating defects along the material’s thickness, researchers can generate new films where nanometer-sized patterns are largely dictated by these defects. This could lead to radical changes in material behavior.
Broader Implications and Future Applications
While the initial study focused on perovskite oxides—a class of materials increasingly used in solar cells and other applications—the researchers believe this method is adaptable to various types of thin materials. The potential benefits are far-reaching. It opens a pathway towards developing electronic devices that harness the unique properties conferred by these controlled defects.
The research team included Jay Shah, Silu Guo, Mayank Tanwar, Donghwan Kim, Sreejith Nair, Matthew Neurock, Turan Birol, and Bharat Jalan, all from the Department of Chemical Engineering and Materials Science, along with Fengdeng Liu from the Department of Electrical and Computer Engineering.
In essence, this research demonstrates that strategically introducing imperfections can unlock entirely new functionalities in nanomaterials, paving the way for a new era of materials design.
This innovative approach to materials engineering could revolutionize nanotechnology by offering a precise and versatile method for creating materials with tailored properties at the nanoscale
