For all you fans of nanotech out there, a friend just sent me a link to instructions for building a scanning tunnelling microscope, from the University of Muenster.

Scanning tunneling microscopy, developed by Binnig and Rohrer in the early eighties, allows the investigation of molecular and also atomic structures. It is the only technique with such a high resolution, that even works in air and in liquid.

The STM consists of a very fine, electrically conducting tip, which is guided over a sample surface at an extremely small distance. Owing to an applied voltage a current flows between tip and sample, where the variation of the current reveals information about the electronic structure of the surface and can also render a height relief. A computer is used to collect single scan points and calculates a detailed map of the sample surface.

Today tunneling microscopy is a standard technique in nanoscience, which is not only used to investigate samples at the atomic scale, but can be employed to construct structures atom by atom as well.

Istructions here.