Chongqing - Chongqing University, leading as the primary author, recently published groundbreaking research titled "3D Microscopy at the Nanoscale Reveals Unexpected Lattice Rotations in Deformed Nickel" in the prestigious journal Science. This study marks a significant advance in nanotechnology.

Led by Professor Huang Xiaoxu from Chongqing University's College of Materials Science and Engineering, the team's development of a one-nanometer resolution 3D transmission electron microscopy technique represents a major global breakthrough in nano-scale 3D imaging technology.

Huang Xiaoxu is a professor from Chongqing University College of Materials Science and Engineering. (Photo/CQU NEWS)

Smaller grains boost material performance

"Most of the materials in our natural world and synthetic materials are crystalline, composed of many small grains," Professor Huang explained. 

Huang clarified that each grain comprises neatly arranged atoms, and parameters such as the size, shape, internal atomic arrangement orientation, spatial distribution of these grains, and their interfacial parameters (i.e., grain boundaries) play a decisive role in the material's performance.

"Generally, the smaller the grain size, the better the performance," Huang said.

"However, traditional electron microscopy can only observe the surface of micro and nano-device samples or view two-dimensional projections of the material's internal three-dimensional structure.," said Huang. "This severely limits our understanding of the material's microstructure and is insufficient for our research needs."

He added, "To deepen our understanding of material mechanisms and improve their performance, a true and complete three-dimensional characterization of material structural parameters is essential."

Three-dimensional transmission electron microscopy. (Photo/CQU NEWS)

Crystal orientation 3D reconstruction technology

Over the past decade, Huang's team has technologically transformed traditional transmission electron microscopy. They developed an integrated control system for electron beam scanning, image acquisition, and sample stage, along with new algorithms and a series of analytical software. 

They have pioneered new 3D characterization techniques and devices in transmission electron microscopy, exemplified by crystal orientation 3D reconstruction technology. This innovation achieves three-dimensional characterization of the grain boundary, interface, and crystallographic characteristics of grains with a spatial resolution of one nanometer and crystal orientation resolution of one degree.

Huang said, for instance, the rapid development of information technology demands increasing computational capabilities for logic chips. As transistors shrink, the number and density of metal interconnects in chips have grown significantly. A major cause of chip failure during service is the formation of voids and hillocks in metal interconnects at the nano-scale due to extremely high current densities causing electromigration.

"Our 3D orientation reconstruction technology in transmission electron microscopy can effectively analyze the failure behavior of metal interconnects in electric fields, revealing the relationship between interface crystallography and electromigration, potentially leading to new insights into the failure behavior of metal interconnects," added Huang. "This could inform the design of chips with superior performance."

The impact of surface and interface structures on nano-materials' performance and structure-performance relationship is yet to be fully understood. Further research is needed to control these structures in nano-materials to create materials with optimal properties.

"However, our developed 3D orientation imaging technology in transmission electron microscopy for the three-dimensional structure of nano-material interfaces will provide an effective approach to study these issues," concluded Huang.

Additionally, advancements in three-dimensional characterization techniques at various scales are poised to transform traditional materials science into a field focused on three-dimensional dynamic analysis of materials' internal structure, composition, and crystallography.