Modern scanning electron microscopes (SEMs) have evolved from their clunky predecessors to sleek machines with impressive capabilities. The SEM at the IBM research center is a prime example of this advancement, resembling a computer with a large tank nearby. To showcase the machine’s sensitivity, a demonstration was conducted by John Ott involving two US cents – one facing up and one facing down. By magnifying the images under the electron beam, Ott proved the statement that Abraham Lincoln appears on both sides of the penny.
Unlike traditional microscopes that pass light through samples, SEMs and REMs use secondary electron emission or reflected electrons from surfaces such as a penny. SEMs are often equipped with EDS (energy dispersive X-ray spectrometers) to reveal the surface composition of a sample. Other methods for surface examination include auger spectrometers for isolating thin films, SIMS for material removal using an ion beam, and Rutherford backscatter spectrometry also utilizing an ion beam.
Despite the advancements in SEM technology, there is still a lack of affordable and easily reproducible SEM models. While there have been attempts to create such devices, the high voltages and precise high vacuums required, along with the need for auxiliary devices like sputter coaters for non-conductive samples, present barriers to entry.
The potential for a cheap and repeatable SEM remains untapped, as current models are complex and costly to produce. Researchers are eager for more accessible options in this field, but the challenges in developing a simplified SEM persist. The need for high voltages, precise vacuums, and additional components like sputter coaters pose significant obstacles for creating a budget-friendly SEM.
In conclusion, while SEM technology has come a long way from its early iterations, there is still a gap in the market for an affordable and easily reproducible model. Researchers continue to explore avenues for making SEMs more accessible, but the technical requirements and associated costs remain major hindrances. The quest for a cheap and repeatable SEM continues, with potential for breakthroughs in the future.
Article Source
https://hackaday.com/2024/06/19/what-you-can-see-with-a-sem/
