Although nanotechnology and materials science are complicated topics for many of us, research in these areas is very important to almost everyone. Your digital tools, for example (A flat 3D model shows us how the software works), are completely dependent on it.
Today, all microelectronics are based on semiconductors. These are materials that are not good conductors of electricity. And you can add little other things to them, a process known as doping. This improves the performance of the semiconductor so that it is not always bad.
“In the past, we have doped semiconductors and found (A flat 3D model shows us how the software works) that it significantly changes the electrical properties of the material,” Kasper Aas Hunnestad, PhD student, at NTNU’s Department of Materials Science and Engineering says.
This is all well and good. It’s good when things work. But beyond the fact that it works, we don’t really understand why it works. This is especially true at the atomic level.
“Now, we know very well how we can look very closely at one by one added atoms, which were previously almost impossible to find.
Why “knowing why” is so important So what?
Why the hell do we need to know about an atom and why anything works? Isn’t it enough to know that it works? If so, scientists and chemists will be happy to do the research, but the rest of us won’t benefit much. Dennis Meris Merrethod:
“It’s only when you know what about working, you can plan the item to pick it up. It’s a professor and engineering section, who led the work. In this way, for example, you can create a good, environmentally friendly or cheap thing for the work to be done. Or you can assign a new resource to something you already have very well.
This is also important for future design for sustainable technology. “Often, we want to introduce new ideas into things. For this, we need to know exactly what each atom does,” says Meier.
Advanced imaging techniques make it possible
Hunnestad and his colleagues presented the results of many hours of work using “atom probe tomography” (APT) in a recent paper in Nature Communications.
APT is a state-of-the-art facility that NTNU acquired a few years ago. The machine can provide a three-dimensional representation of what things look like, down to the atomic level, explains Constantinos Hatzoglou. He is a senior engineer at APT Laboratory in the Department of Science and Engineering.
Hunnestad and colleagues used this outstanding ability to study a new type of oxide-based semiconductor with a small amount of added material to support its properties.
Hunnestad says: “Normal microscopy techniques do not allow us to see how small additives attach themselves to semiconductors.
These new results show that investing in the best technical equipment, such as this APT machine, pays off very helpful and helpful for research.
Showing great strength
Searching for APTs is not really easy either. But by bringing together colleagues with different experimental and educational backgrounds – and with hard work and inspiration – the NTNU team has found a solution.
A comparison of atomic probes. The 3D map on the left shows the size distribution of atoms, with each point representing an atom. From APT data, researchers can build accurate models at the atomic scale, as shown on the right. They can identify individual atoms, here titanium (Ti), which have been added to the material (ErMnO3) to tailor its properties. Courtesy: Kasper Aas Hunnestad, NTNU.
It’s not just great success. It also shows the great potential of the APT method for research areas where it has not been applied before. This shows the unique opportunity we have with the state-of-the-art facilities at NTNU’s NanoLab and TEM Gemini Center,” said Meier.
Hunnestad has worked with APT for about three years. He carried out a number of combined microscopy measurements, supported by Antonius van Helvoort and Per Erik Vullum. Van Helvoord is a professor in the physics department of NTNU and a specialist in advanced electron microscopy, while Vullum is a professor II in NTNU, department of physics and a research director in the SINTEF institute.
Hunnestad and Meier are excited about all the exciting possibilities that have emerged from their APT-based research and new ideas for characterizing structures at the atomic scale.
Image of a Titanium Atom Mixed in a Semiconductor
For their recent paper, the same research team focused on Er(Mn,Ti)O3 oxide semiconductors. To achieve this, their colleagues at the Lawrence Berkeley National Laboratory in the United States added a small amount of titanium (Ti) and erbium manganate (ErMnO3).
“With atomic analysis, we can obtain a three-dimensional representation of a single titanium atom embedded in a semiconductor,” explains Meier. “This allows us to connect the new electrical properties of the bottom of each atom.”
Dr Muhammad Zeeshan Khalid is a member of the team led by Sverre Selbach, a professor in the Department of Materials Science and Engineering at NTNU. He completed the experiments with calculations. These calculations provide insight into the effect that individual atoms can have on physical properties.
One of the advantages of what the researchers did was that they could use the method in many other ways. It is not only that the NTNU research team has tested it. “The process and the results are of general interest. They can extend our understanding of oxide semiconductors and materials in general. Research opens up completely new avenues,” says Meier.
Collaborative approaches strengthen research
Many people from different departments of NTNU contributed to make this scientific progress possible. The project was supported by SINTEF, the Research Council of Norway, the Norwegian Micro- and Nano-Fabrication Facility (NorFab), the Norwegian Laboratory for Minerals and Materials Characterization (MiMaC), the Norwegian Center for Transmission Electron Microscope (NORTEM) and NTNU Nano.
Researchers indicate that this collaborative effort demonstrates the power of interdisciplinary research. It shows what can be achieved with powerful modern equipment.
The details of how Hunnestad achieved such remarkable results are not easy for most of us to digest. But the links and research articles below will give you something to chew on if you want to dig.
