Microscopy for Materials Characterization: Illuminating Structures With Light and Electrons
Elaine F. Schumacher
American Laboratory - September 9, 2014
Engineered materials abound in products that we use every day. They can range from a bulk material like the glass in a window to a dispersion of titanium dioxide nanoparticles in a sunscreen formulation. Every material, from the plastic in the sole of a running shoe to the semiconductor chip in a laptop, has undergone a development process that includes an iterative cycle of characterization and performance testing. By gaining insight into the structure and composition of a material and linking that knowledge to properties that govern performance, designers can build better products while shortening development time.
Demands for improved product performance continually evolve. We want things that are smaller, lighter, faster, stronger, and greener. As performance specifications tighten, the need to understand and design materials moves from the bulk to the atomic level. Microscopy in all of its forms can provide insights into key material characteristics, elucidating size, texture, morphology, crystallinity (or lack thereof), elemental composition, and electronic state, at scales ranging from several micrometers to single atoms. Perhaps surprisingly, microscopes at two ends of the resolution scale, the light microscope and the transmission electron microscope, are very similar in function and in the types of information provided. A comparison of some key features will illustrate this similarity, and will also demonstrate why microscopy tools and techniques are central to materials characterization.