A research team has created an innovative way to observe alterations in materials at the atomic scale. This new technique paves the way for enhanced understanding and creation of sophisticated materials suitable for quantum computing and electronics.
A research team from the Oak Ridge National Laboratory, part of the Department of Energy, has created an innovative way to observe alterations in materials at the atomic scale. This new technique paves the way for improved understanding and creation of sophisticated materials suitable for quantum computing and electronics.
The newly developed technique, named Rapid Object Detection and Action System (RODAS), merges imaging, spectroscopy, and microscopy methods. It captures the properties of temporary atomic structures as they form, offering extraordinary insights into how material properties change on the atomic level.
Previous methods that combined scanning transmission electron microscopy (STEM) with electron energy loss spectroscopy (EELS) faced limitations, as the electron beam could alter or damage the materials under investigation. As a result, scientists often ended up measuring modified states rather than the actual properties of the materials. RODAS addresses this issue and integrates a system capable of dynamic computer-vision imaging that employs real-time machine learning.
In its analysis, RODAS focuses solely on regions of interest. This allows for swift analysis — within seconds or milliseconds — in contrast to the minutes sometimes needed by other STEM-EELS techniques. Significantly, RODAS extracts vital information without harming the sample.
Every material contains defects, which can greatly impact various properties, including electronic, mechanical, or quantum attributes. Defects can arrange themselves at the atomic level in multiple ways, both naturally and in response to external forces like electron beam exposure. Unfortunately, the local properties of these defect arrangements aren’t well understood. While STEM methods can experimentally observe such configurations, studying specific arrangements without altering them proves to be quite challenging.
“Grasping defect configurations is essential for the advancement of next-generation materials,” stated Kevin Roccapriore, lead author of the study from ORNL’s Center for Nanophase Materials Sciences. “With this knowledge, we could intentionally design a specific arrangement to achieve a desired property. This area of research is distinct from observation and analysis but represents a potentially impactful path for future development.”
Realizing the potential of quantum materials
The research team applied their technique to single-layer molybdenum disulfide, a promising semiconductor for quantum computing and optical applications. Molybdenum disulfide is particularly noteworthy because it can emit single photons from defects known as single sulfur vacancies. In this context, a single sulfur vacancy indicates the absence of one sulfur atom from its honeycomb lattice structure, which refers to the arrangement of the atoms. These vacancies can cluster together, producing unique electronic characteristics that make molybdenum disulfide advantageous for cutting-edge technological uses.
By examining molybdenum disulfide and similar single-layer materials, scientists aim to address crucial questions regarding atomic-scale optical and electronic properties.
A new chapter in materials science
The RODAS technique marks a considerable advancement in the characterization of materials. It enables researchers to dynamically investigate the relationships between structure and properties during analysis, focus on specific atoms or defects for measurements as they form, collect diverse defect data efficiently, adaptively identify new atomic or defect classes in real-time, and minimize damage to samples while maintaining thorough analysis.
Utilizing this technology on a single layer of vanadium-doped molybdenum disulfide, the research team enhanced its understanding of defect formation and evolution when exposed to electron beam radiation. This method allows for the exploration and characterization of materials in dynamic states, providing deeper insights into how materials respond to different stimuli.
“Techniques in materials science, such as advanced electron microscopy, continue to broaden our understanding of the physical world, and systems like RODAS could significantly accelerate discovery and innovation,” said Roccapriore. “The capacity to observe and analyze materials at the atomic level in real-time holds promise for extending the limits of computing, electronics, and beyond, ultimately facilitating the creation of transformative technologies.”
This research was supported by ORNL’s Laboratory Directed Research and Development program as part of their Interconnected Science Ecosystem (INTERSECT) initiative. The STEM experiments received backing from the DOE Office of Science Basic Energy Sciences, Materials Sciences and Engineering Division and were conducted at the Center for Nanophase Materials Sciences, a DOE Office of Science user facility at ORNL. Additionally, this work was part of the Center for the Science of Synthesis Across Scales, an Energy Frontier Research Center backed by the DOE Office of Science Basic Energy Sciences at the University of Washington.
