2nd/3rd Year Undergraduate Experiments in Physical Chemistry
3.02 Scanning Tunnelling Microscopy
Introduction to the Experiment || Location of the Experiment || Useful Web Links
You will be aware from courses in quantum mechanics, that electrons have both wave- and particle-like properties. In this experiment, which provides strong evidence for the wave-like nature of electrons, you will investigate one of the many new methods for investigating the properties of surfaces at the molecular level.
Scanning probe microscopes are used increasingly in research as a means of interrogating the chemical and electronic structure of surfaces. The term Scanning Probe Microscope encompasses several types of instrument, which have similar architecture and features. In each case, a tiny probe is positioned very close to a surface, and moved in a raster fashion across the surface (in the manner in which an electron beam is swept across the screen of a television set). Measurements are taken at regular intervals during a scan (usually at a rate of several kHz) and the very fine positional capability of the probe enables one to investigate such factors as electron energy states, magnetic field strengths or interatomic forces at the surface, depending upon the type of instrument.
These instruments work at near atomic resolution, so their use has opened up a wide range of new and fruitful areas of research, including studies of semiconductor structure, atomic level topography, probing of organic conductors, and studies of the interaction between biomaterials and biological tissues.
In this experiment you will use a Scanning Tunnelling Microscope to take images of surfaces down to atomic resolution.
Upper Teaching Laboratory, computing area.
Scanning tunnelling microscope (Images from the Wien STM gallery)
Updated October 10, 2003.