Study of Solid State Surfaces using a Scanning Tunnelling Microscope
Supervisor: Dr. habil. Michael Lorenz, Wolfram Fritzsche
In the experiment Scanning Tunneling
Microscopy STM the lateral electron density distribution of solid
state surfaces will be depicted. This allows under optimised conditions
to visualize single atomic positions. Beside it, more extended objects
as quantum dots and monolayer terraces with dimensions in the nm-range
will be represented.
The scanning tunneling microscope is based on the quantum mechanical
tunnel effect. In addition to the imaging of the surfaces,
current-voltage curves in dependence on the distance from tip to
surface and current-distance curves are recorded. By fitting
appropriate model equations the barrier height of the particular
tip-sample combination can be determined.
Methodical aspects cover the different
scan modes of a STM and the piezoelectric materials which enable the
STM experiments by controlling the tip position with sub-nm accuracy.
The experiment gives direct practical experience by application of this
modern method of surface physics.
Versuchsunterlagen