University of Michigan researchers have developed a method to achieve high-resolution 3D imaging at the one-nanometer scale. The method presents a novel application of multi-modal imaging to combine microscopy signals and achieve high-resolution imaging.
"Seeing invisible worlds, far smaller than the wavelengths of light, is absolutely critical to understanding the matter we are engineering at the nanoscale, not just in 2D but in 3D as well," said Robert Hovden, an associate professor of materials science and engineering at U-M
To date, researchers typically had to choose between 3D imaging of a structure or 2D imaging of its chemical distribution. Both techniques rely on scanning transmission electron microscopes to accelerate an electron beam through a sample material to resolve structures. The major drawback of these methods is that to achieve high-resolution imaging a significant amount of energy is required, and in the case of chemical imaging, the energy required is on the cusp of the point where materials will begin to melt if exposed to additional energy.
This energy dose issue is especially consequential in 3D chemical imaging which requires numerous chemical images. To overcome the dose issue, the team developed a method known as "multi-modal electron tomography" to collect images at every tilt angle while chemical imaging only occurs every few tilts. After imaging, a multi-modal algorithm takes the information and combines the signals into a 3D structure and chemistry.
Published in Nature Communications, the method is capable of imaging organic compounds and metals simultaneously.
"Our solution takes advantage of all the complementary signals that are present in our microscope by promoting communication between a signal that doesn't require much dose and a very dose hungry signal," said Jonathan Schwartz, a doctoral graduate of materials science and engineering from U-M.
Multimodal imaging is growing in popularity amongst the world's engineers. The technique allows researchers to combine two different signals to enhance information and further our understanding of materials science.
"This is one of the first big results of the power of multimodality in our field. It's exciting to still find new ways to see matter at these small scales," said Hovden.