New electron microscopy method sculpts 3-D structures at atomic level

November 9, 2015 by Morgan Mccorkle
ORNL researchers used a new scanning transmission electron microscopy technique to sculpt 3-D nanoscale features in a complex oxide material. Credit: Department of Energy's Oak Ridge National Laboratory

Electron microscopy researchers at the Department of Energy's Oak Ridge National Laboratory have developed a unique way to build 3-D structures with finely controlled shapes as small as one to two billionths of a meter.

The ORNL study published in the journal Small demonstrates how scanning transmission electron microscopes, normally used as imaging tools, are also capable of precision sculpting of nanometer-sized 3-D features in complex oxide materials.

By offering single atomic plane precision, the technique could find uses in fabricating structures for functional nanoscale devices such as microchips. The structures grow epitaxially, or in perfect crystalline alignment, which ensures that the same electrical and mechanical properties extend throughout the whole material.

"We can make smaller things with more precise shapes," said ORNL's Albina Borisevich, who led the study. "The process is also epitaxial, which gives us much more pronounced control over properties than we could accomplish with other approaches."

ORNL scientists happened upon the method as they were imaging an imperfectly prepared strontium titanate thin film. The sample, consisting of a crystalline substrate covered by an amorphous layer of the same material, transformed as the passed through it. A team from ORNL's Institute for Functional Imaging of Materials, which unites scientists from different disciplines, worked together to understand and exploit the discovery.

"When we exposed the amorphous layer to an electron beam, we seemed to nudge it toward adopting its preferred crystalline state," Borisevich said. "It does that exactly where the electron beam is."

The use of a scanning , which passes an electron beam through a bulk material, sets the approach apart from lithography techniques that only pattern or manipulate a material's surface.

"We're using fine control of the beam to build something inside the solid itself," said ORNL's Stephen Jesse. "We're making transformations that are buried deep within the structure. It would be like tunneling inside a mountain to build a house."

The technique offers a shortcut to researchers interested in studying how materials' characteristics change with thickness. Instead of imaging multiple samples of varying widths, scientists could use the microscopy method to add layers to the sample and simultaneously observe what happens.

"The whole premise of nanoscience is that sometimes when you shrink a material it exhibits properties that are very different than the bulk material," Borisevich said. "Here we can control that. If we know there is a certain dependence on size, we can determine exactly where we want to be on that curve and go there."

Theoretical calculations on ORNL's Titan supercomputer helped the researchers understand the process's underlying mechanisms. The simulations showed that the observed behavior, known as a knock-on process, is consistent with the electron beam transferring energy to individual atoms in the material rather than heating an area of the material.

"With the electron beam, we are injecting energy into the system and nudging where it would otherwise go by itself, given enough time," Borisevich said. "Thermodynamically it wants to be crystalline, but this process takes a long time at room temperature."

The study is published as "Atomic-level sculpting of crystalline oxides: towards bulk nanofabrication with single atomic plane precision."

Explore further: ORNL microscopy finds evidence of high-temperature superconductivity in single layer

More information: Small,

Related Stories

Researchers probe invisible vacancies in fuel cell materials

August 22, 2012

( -- Knowing the position of missing oxygen atoms could be the key to cheaper solid oxide fuel cells with longer lifetimes. New microscopy research from the Department of Energy's Oak Ridge National Laboratory is ...

Recommended for you

Nano-decoy lures human influenza A virus to its doom

October 25, 2016

To infect its victims, influenza A heads for the lungs, where it latches onto sialic acid on the surface of cells. So researchers created the perfect decoy: A carefully constructed spherical nanoparticle coated in sialic ...

New method increases energy density in lithium batteries

October 24, 2016

Yuan Yang, assistant professor of materials science and engineering at Columbia Engineering, has developed a new method to increase the energy density of lithium (Li-ion) batteries. He has built a trilayer structure that ...

Nanofiber coating prevents infections of prosthetic joints

October 24, 2016

In a proof-of-concept study with mice, scientists at The Johns Hopkins University show that a novel coating they made with antibiotic-releasing nanofibers has the potential to better prevent at least some serious bacterial ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.