Ready for action: New scanning transmission electron microscope in the Nano Imaging LabSNI INSight December 2021
The staff of the SNI Nano Imaging Lab (NI Lab) have commissioned a new scanning transmission electron microscope (STEM), which is prized for its high resolution and magnification. Dr. Marcus Wyss is currently conducting the inaugural research projects using the device and is looking forward to taking on new tasks and challenges.
In fall of 2018, a survey of research groups at the University of Basel found that some groups were in dire need of a new scanning transmission electron microscope with improved resolution and analysis capabilities. After several minor hiccups and a few more substantial issues, this new device, manufactured by the company Jeol, now stands ready for operation in a specially redesigned room located in the basement of the Department of Pharmaceutical Sciences. The new microscope allows the NI Lab team to capture high-resolution images of nanostructures inside thin samples and perform material analyses.
The new TEM/STEM can take measurements in two different modes: The conventional or fixed beam mode employs a fixed beam of electrons, while rastered beam mode uses an extremely fine beam of electrons to scan the sample, pixel for pixel. The device is equipped with a so-called cold field emission gun, which enables it to produce high-resolution images.
Researchers can use this new microscope to magnify objects up to one million times, thus rendering individual atoms visible. The microscope’s maximum resolution is 0.19 nanometers.
This excellent resolution allows researchers to view the crystal structure of samples, thereby revealing the arrangement of individual atoms. Researchers can use this information to conduct minute analyses of the interfaces in the substructures of nanowires, for instance. Moreover, the new STEM serves a broad range of applications in the study of diamond flaws and two-dimensional materials. Thanks to the energy-dispersive X-ray spectroscopy (EDX) system installed inside the microscope, researchers are not only able to generate images of their samples; they can also analyze specific chemical compositions at different points within the sample.
Services provided by the Nano Imaging Lab include sample analysis and generation of highly detailed images as well as complete sample preparation. NI Lab staff use the focused ion beam (FIB) to produce extremely fine slices of samples – which can be cut in all three dimensions – for later analysis with the STEM. Biological samples must first be embedded in resin. Thanks to their collaboration with the Bio EM Lab, the NI Lab is also equipped to perform this part of the sample preparation process.
The STEM is ready for operation and the first research groups from the University of Basel are currently preparing their initial samples. Companies from across the region have also taken an interest in the microscope and are currently in negotiations with the NI Lab.
Dr. Marcus Wyss, who joined the NI Lab team in summer of 2021 after working as a postdoc in the group under Argovia Professor Martino Poggio, serves as the main point of contact for any issues involving the new microscope. He is currently immersing himself in the subject. Early next year, he will visit the Netherlands to learn additional tips and tricks for using the STEM to work on nanowires from experts at the Eindhoven University of Technology. “I’m excited about all the different research questions we’ll be able to explore using the new STEM, and I’m looking forward to helping our clients from different fields conduct their analyses,” says Marcus Wyss.