Doc. RNDr. Stanislav Haviar, Ph.D. is a researcher at the Department of Physics, Faculty of Applied Sciences, University of West Bohemia in Pilsen. The department focuses primarily on materials engineering, including the preparation of thin-film materials using plasma-based technologies such as magnetron sputtering.
The goal of researchers at FAS UWB is not only to understand the resulting material itself, but also the fundamental physical principles governing its formation. The institution, located in a modern research campus, also bridges academic research with applied industrial development. Since last year, this effort has been supported by a Tescan AMBER 2 electron microscope equipped with advanced instrumentation, including a unique 4D-STEM detector. We asked Stanislav Haviar to tell us more about his work.
The range is broad. One of our core areas is thin-film materials with various applications. Particularly interesting are thermochromic coatings based on vanadium dioxide (VO₂). These materials modulate infrared transmittance depending on ambient temperature. When applied to architectural glass, they ideally allow heat to pass into the interior during winter while blocking it in summer. The objective is to optimize the material so that it minimally affects visible light transmission.
Historically, our department has also been strong in mechanically and thermally resistant coatings for industrial applications, such as cutting tools. Another significant area is energy-related materials - for example, coatings for water splitting or materials associated with hydrogen technologies.
My personal focus is on nanostructured gas sensors, particularly hydrogen sensors, where we aim to reduce the use of expensive noble metals and develop more sustainable alternatives for sensitive-layer preparation.
I should also mention the second major branch of our research: the plasma-based processes used for material synthesis. A deep understanding of plasma processes enables us to design and fabricate innovative functional materials.
Yes, collaboration with industrial partners is important to us. Many of our graduates go directly into industry, especially European companies specializing in functional coatings - hard, protective, low-friction, and others. The Faculty of Applied Sciences maintains strong links with applied research, even though our group is closer to fundamental research. Nevertheless, industry collaboration is natural, partly because students become involved in real research projects very early in their studies.
Electron microscopy is a key tool for both research and teaching. Students are introduced to experimental methods from their first year of undergraduate study through project-based learning. They progressively work with analytical techniques ranging from basic imaging to advanced methods such as EDS analysis.
At the master’s and doctoral levels, students work on specific research topics and are capable of independently performing measurements and analyzing data.
The primary motivation was the need for greater efficiency and automation. We frequently work with larger series of samples while optimizing deposition parameters. This requires repeatable measurement conditions and rapid analysis.
The new system allows scripting, batch acquisition, automated return to specific sample locations, and significantly increases data throughput. This saves time - our most valuable resource.
Previously, much of the work was manual and highly dependent on operator experience. Today, we can prepare cross-sectioning templates, automatically image entire sample series, and ensure that no critical image in a dataset is missing. That is essential, because missing a single sample in a series often means restarting an experiment and losing valuable time.
The sample types are diverse. A typical specimen consists of a substrate — glass, silicon, sapphire, or ceramic - coated with a thin film. Thickness ranges from several micrometers down to tens of nanometers.
In optical materials, these are often multilayer structures; in sensors and nanocomposites, highly nanostructured thin films.
We use FIB conventionally for TEM lamella preparation, but also frequently for cross-sections that allow rapid evaluation of thickness, structure, and material changes — for example, after thermal loading. FIB also enables the fabrication of micromechanical structures such as micro-cantilevers or micropillars, which we subsequently test in situ inside the microscope chamber.
We employ a gallium ion beam, which is fully sufficient for the material systems and dimensions we work with.
EDS is a key technique for elemental analysis. The windowless detector allows detection of light elements such as oxygen or boron and enables operation at low accelerating voltages, resulting in improved lateral resolution. This is crucial when studying thin oxide layers and interfaces.
Low-voltage performance is essential for us. If the microscope does not provide sufficient resolution at low accelerating voltages, no additional adjustments will compensate for that.
Thanks to this capability, we often do not need to coat samples - proper grounding is sufficient. If coating is required, we use a sputter coater and apply very thin chromium layers, though the operator must remain aware that coating can influence surface morphology.
4D-STEM enables us to record diffraction information at every probe position across a scanned lamella - in our case directly inside the FIB chamber, without transferring the lamella elsewhere.
The result is a four-dimensional dataset from which various image types can be reconstructed using virtual detectors. A key advantage is the live preview capability, allowing us to locate the region of interest, focus properly, and only then decide whether to store the full dataset.
A typical application is nanocomposite materials, where crystalline grains on the order of tens of nanometers are embedded in an amorphous matrix. Chemically, these phases may differ only slightly, making them indistinguishable in conventional imaging contrast. Diffraction contrast, however, clearly reveals the crystalline phase, its orientation, and whether it nucleates at the substrate interface or forms within the bulk. These insights are extremely valuable for our research. It is also highly convenient that the lamella can be further polished or cleaned directly using the FIB if the diffraction pattern quality is insufficient.
The instrument was essentially customized according to our specifications. It represents a unique combination of state-of-the-art technologies, and the result is a system operating in exactly the configuration we required.
Not entirely. Some information is accessible only at the atomic scale, where TEM remains indispensable.
However, in many cases, information at the scale of tens of nanometers is sufficient. In such situations, 4D-STEM in SEM provides an adequately precise answer - with the additional advantage of broader contextual information from the entire sample.
We collaborate with external research facilities for detailed TEM analysis when necessary. Even in those cases, 4D-STEM assists us by enabling better pre-selection of samples for comprehensive TEM investigations.
For an experienced user, it represents a significant step forward. Today, I can set up a measurement series in one hour that previously required an entire morning of manual work. The resulting images are consistent and directly comparable.
Automation tools, setup wizards, and particularly the well-designed help system greatly facilitate operation. After basic training, I was able to prepare a TEM lamella within two days using only the built-in guidance.
Historically, it was often the case that the more robust the hardware, the less usable the software. That is not the case here. The help system is well-structured, clear, and practical. This is particularly important in an academic environment, where users and students with varying levels of experience rotate through the laboratory.
Of course, problems may arise if a completely unsuitable sample is inserted into the chamber. However, if basic operational rules are followed, the clear collision model, warnings, and logical motion control provide confidence that the instrument cannot be damaged.
In the future, we are considering integration of Time-of-Flight mass spectrometry, particularly for studying lithium in battery applications. Lithium is very difficult to detect via EDS - even with a windowless detector - whereas mass spectrometry allows monitoring of sputtered ions directly from the interaction site.
The microscope itself does not develop materials. It is a feedback tool that tells us whether we prepared the material correctly, how it behaves under load, and where its limitations lie.
Whether we are optimizing thermochromic vanadium dioxide layers, developing metallic glasses, or designing platinum-free catalytic materials, we always require a combination of structural, chemical, and functional information.
The integration of SEM, FIB, EDS, and 4D-STEM in a single platform now allows us to obtain this information in one place and significantly accelerate the entire research process.
Thank you for the interview, and we wish you continued success in your research.
Written by Jana Šilarová
Marketing Director, Tescan