Monday, September 7, 2009

Advancements in Microscopy

IBM researchers have produced the first Atomic Force Microscope (AFM) with a carbon monoxide. This has enabled them to produce an image of a molecule, pentacene, which is an organic semiconductor. Some think this development is indicative of future successes with electronic design on an atomic level.

AFMs operate “like fingers reading Braille.” A microscopic tip is guided over the surface of a sample. The reading is formed by tip fluctuations, in what is called a “force-map.” In contrast, electron microscopes use particle beams of electrons to create an image. Although AFMs have existed since 1986, satisfactory imaging has not been possible until now. Readings were formerly disrupted by electrostatic and Van der Waals interactions between the AFM tips and samples. This issue was avoided by the attachment of a single carbon monoxide molecule to the AFM tip.

Unfortunately, this technique cannot be practiced in open air; it must be done in a very high level vacuum at an extremely low temperature (approx. 5 K). The technique also takes a long time (> 20hr. per scan). Additionally, the CO tip attachment does not apply to every sample. However, the petacene image represents a significant development in the field of microscopy and the possibility of breakthroughs in processing power and efficiency.

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