“Stm” Scanning Tunneling Microscopy

Scanning Tunneling Microscopy is a recently developed technique within the area of Scanned Image Microscopy that is based on tunneling between two conducting electrodes. This method offers, for the first time, the possibility of direct, real space determination of surface atomic and electronic structure in three dimensions on an atomic length scale, including nonperiodic structures. In this technique a sharp metal tip, mounted on a piezoelectric tripod that forms an orthogonal coordinate system, is brought to within a few Angstroms of the sample surface without “touching” the region to be scanned. A tunneling current I, on the order of 0.1 to 1 nA, is established by applying a bias between the tip and sample. The tunneling current is given to first order by;