Scanning Probe Microscopy: Principles

For the techniques to provide information on the surface structure at the atomic level:

Figure 20.04: Tip nature for imaging.

• The position of the tip with respect to the surface must be very accurately controlled (to within about 0.1 Å) by moving either the surface or the tip.

• It is possible to preciously control the relative positions of tip and surface by ensuring good vibrational isolation of the microscope and using sensitive piezoelectric positioning devices.

• The tip must be very sharp - ideally terminating in just a single atom at its closest point of approach to the surface (see Figure 20.04).