An international collaboration supported by the Physics for Future (P4F) project has delivered a new diagnostic method for more precise control of plasma deposition processes. A Czech and Swedish research team combined two original approaches to plasma diagnostics to create an experimental system that helps refine the preparation of thin vanadium dioxide (VO₂) films. The method could improve the manufacture of thermochromic coatings for smart windows, as well as semiconductor and optical thin films used, for example, in optical sensors, detectors and photonic devices.
The project builds on a long-standing collaboration between researchers at the Institute of Physics of the Czech Academy of Sciences and Linköping University. At the Institute of Physics, researchers developed a radio-frequency (RF) probe to measure plasma parameters. Professor Daniel Lundin’s team in Sweden proposed using the magnetron target itself as a diagnostic probe during the deposition process. Combining these two approaches produced a unique experimental system that makes it possible to monitor the plasma process without intervening in the deposition chamber.
The Physics for Future initiative provided a further important impetus for the collaboration. Through the initiative, postdoctoral researcher Xiao Li joined the Institute of Physics, where she collected an extensive dataset on plasma behaviour during the preparation of vanadium dioxide films using the joint experimental system. Analysis of the data enabled a better understanding of the physical relationships governing the process and showed which plasma parameters best indicate its stability and can be used to control it more precisely.
“The most valuable aspect of the project was the combination of different areas of expertise and experience. Thanks to the unique experimental setup and the extensive set of measurements, we were able to better understand plasma behaviour during deposition and identify the parameters that are most important for process control. These findings can support not only further research, but also the future industrial use of plasma technologies,” says Zdeněk Hubička, Head of the Low-Temperature Plasma Department in the Division of Optics.
Although the method was validated in the preparation of vanadium dioxide films, its potential is much broader. Control of the reactive HiPIMS process is important not only for producing thermochromic VO₂ coatings; it is also a promising approach to preparing other semiconductor and optical thin films using pulsed magnetron deposition methods.
The extensive experimental dataset now also serves as a basis for developing artificial intelligence and machine-learning algorithms. Their aim is to train systems to recognise the state of the plasma process in real time and, in the future, enable its intelligent automated control.
“This result is an excellent example of how international collaboration accelerates the connection between cutting-edge basic research and the prospect of practical application. Combining Czech developments in diagnostic methods with the experience of our Swedish colleagues created a unique experimental system that helped us better understand plasma processes. At the same time, it laid the foundation for new diagnostic technologies with significant potential for future industrial collaboration and their gradual transfer into practice,” says Alexandr Dejneka, Head of the Division of Optics at the Institute of Physics of the Czech Academy of Sciences.
The research findings were published in the journal Plasma Sources Science and Technology.