IN TOOLS

Before you can make something, you have to have the tools. For this reason, this category has the greatest number of established companies. By tools we mean the collection of technologies that allow us to see, manipulate and engineer at the atomic level.

STMs. It is now twenty years since the scanning tunneling microscope (STM) was invented, allowing us to see atoms for the first time. The STM works by detecting small currents flowing between the microscope tip and the sample being observed (the current flows because of quantum mechanical tunneling).

AFMs. Five years later a device with similar capabilities, the atomic force microscope (AFM), was invented, which has a tiny probe on the end of a cantilever (like a springboard). The probe makes contact with the surface of the sample and, as it moves over it, is deflected by the variations in the surface, causing the cantilever to bend. A laser beam detects the bending of the cantilever and, again, we get atomic resolution. Advances are being made in using these in various mediums, including liquids, which is particularly useful for looking at biological samples.

Scanning Probe Microscopes. The AFM and the STM are collectively called scanning probe microscopes and can not just produce images but actually move atoms around, as was demonstrated when IBM used an SPM to write the company's letters in xenon atoms (see picture). SPMs have potential for high-density data storage technologies and can be used to write nanoscale lines, as in dip-pen nanolithography. In case you are imagining some vast machine in a laboratory, AFMs and STMs can be bought as devices not much bigger than a mouse that plug into a computer's USB port.