As is often the case in scientific research, sometimes the biggest results can come from the smallest particles. Nanoimaging, or the process of using advanced imaging techniques to view and characterize structures with nanometer resolution, accomplishes just that. 

At 4D LABS, scanning electron microscopy techniques are used to assess nanomaterials for fuel cell applications.structures with nanometer resolution, accomplishes just that.

Two research institutions, one at the University of Maryland and the other at Simon Fraser University in Burnaby, Canada are at the forefront of providing nanoimaging capabilities to their user communities.

4D LABS, Simon Fraser University

As a collaborative nanoimaging, nanofabrication and LASIR facility located in Burnaby, 4D LABS houses a suite of tools that enable the visualization of material structures and compositions with micron- to nanometer-scale information using focused electron or ion beams. Led by Nathanael Sieb, Director of Operations and Administration, researchers at 4D LABS (like Xin Zhang, Staff Scientist), work with clients to answer real-world material science questions. The >$50 million institute has a variety of nanoimaging equipment, from high-resolution electron and ion beam microscopes to sample preparation tools.

“Our research is focused on understanding composition-related and structure-related properties,” Sieb told Laboratory Equipment. “It covers sample screening for process optimization, discovery of unusual structures or materials, and failure analysis and quality control in academic and industrial semiconductor device fabrication processes and other manufacturing processes.”

Sample prep is an integral step in the nanoimaging process, and researchers at 4D LABS have access to a variety of tools to aid in the process. For example, gold and carbon coaters coat non-conductive samples for imaging while minimizing unwanted sample charging. This step prevents the distortion of sample information obtained under a scanning electron beam. Microtomes cut thin slices suitable for transmission electron microscopy, ensuring optimal electron transparency and best results from a detailed, nanoscale analysis. Ion millers mill samples so they’re thin enough for transmission electron microscopy. Plasma cleaners remove light organic contamination on samples to ensure a higher accuracy of data and efficiency in collection.

4D LABS boasts four scanning electron microscopes (SEM) equipped with elemental analysis capability, and two with focused ion beam (FIB) technology. The institution also has three transmission electron microscopes (TEM), two with elemental analysis capability. 

SEM is a technology routinely used in nanoimaging. During SEM, an electron beam scans a material’s surface and interacts with its atoms while an electron detector collects secondary electrons incurred by the beam for image formation. The best SEM resolution is a bit below 1 nm, according to the experts at 4D LABS. If additional resolution is needed, TEM is necessary and often requires more sample preparation. During TEM, an electron beam passes through a thin sample. Then, transmitted electrons form images that contain sample structure information.

FIB techniques can be used for material etching, prototype nanofabrication or imaging, Zhang explained to Laboratory Equipment. The technology is perfect for small area and prototype device fabrication. FIBs can write specific structures, such as grating lines and hole/pillar arrays in substrates of various materials and shapes. Plus, FIB technology often enhances SEM capabilities by revealing the internal materials and structures of a sample.

“For example, micro-chip manufacturers need to visualize the 3-D structure layout of their chips for quality control or device optimization. The FIB/SEM slice and view technology can be used to mill and image materials/devices layer by layer,” Zhang explained. “The collected image stacks can then be reconstructed into a 3-D volume where material and structural information can be extracted.”

Two FIB/SEM systems with gallium ion source and one helium ion microscope are also available for users to complete FIB work.

NanoCenter AIMLab, University of Maryland

The Advanced Imaging and Microscopy Laboratory ( AIMLab), formerly dubbed the Nanoscale Imaging, Spectroscopy and Properties Laboratory (NISPLab), is situated on-campus in College Park, M.D. Directed by Wen-An Chiou, the AIMLab is one of three components to the NanoCenter (additional spaces include nanofabrication and nanooptics laboratories). Leaders of the AIMLab say they’re proud of its nanoimaging capabilities and electron microscopy facilities that allow nearly all prepared materials to be imaged and analyzed down to an atomic scale.

AIMLab has three fully equipped SEMs (two attached with FIB capabilities) and two TEMs. One of the TEMs is an ultra-high resolution field emission TEM and S/TEM (scanning transmission electron microscopy). These electron microscopy instruments are imperative to the advanced imaging operations of the laboratory. With their nanoimaging capabilities, these powerful microscopes are well-suited for a variety of research in engineering applications and physical sciences—including astrogeological investigation, like the study of the early formation of evolved asterodicdal crust. There’s more, too.

“The most exciting thing we are doing is in-situ battery research, in which we operate nanostructured batteries under the TEM and watch them work (such as in-situ atomic-scale imaging of electrochemical lithiation in silicon),” Martha J. Heil, Science Communicator for the Maryland NanoCenter, told Laboratory Equipment. “This [project] is the forefront of our research.”  

An additional in-situ electron microscopy capability at AIMLab is cryo-TEM, which provides nanoscale imaging at liquid nitrogen temperature. At the same time, ultra-fast heating holders allow researchers to carry out experiments at high temperatures. This process allows Chiou and his colleagues to examine the dynamic change of microstructure in TEM and SEM.

The FIB technology at AIMLab uses a focused beam of gallium or other ion (like xenon). The technology is utilized primarily in the semiconductor and materials science fields, particularly for ablation of materials, deposition and analysis of specific sites. FIBs can also be incorporated into systems with both electron and ion beam columns, adding versatility and cohesion in research projects. The new FIBs are “just coming to life” at AIMLab, so more research using the laboratory technique is forthcoming.

Chiou told Laboratory Equipment that the FIB is a very powerful tool in modern day scientific and engineering research, and AIMLab has two of the most advanced and fully equipped FIBs in the nation.

“A FIB is very much like a Swiss Army knife,” he said. “It uses ions to slice/cut/drill your samples/materials and also utilizes electrons to image the minute structures and even repair nano devices. It can also analyze the microchemistry of your samples and present the data in 3-D.”

Shared facilities

Both 4D LABS at Simon Fraser University and AIMLab at the University of Maryland are shared open-access user facilities, also known as contract research organizations. In other words, these not-for-profit laboratories aren’t just for local university students—government agencies, researchers from other academic institutions and businesses all utilize the wealth of personnel expertise and highly specific laboratory equipment housed in both spaces. Intimately connected to the universities near which they’re situated, both nanoimaging centers provide a resource not only for those in academia but also for their surrounding scientific and business communities.