Download Scanning Tunneling Microscope

Scanning Tunneling Microscope
Iron atoms on the surface of Cu(111)
The scanning tunneling microscope was
developed at IBM Zürich in 1981 by Gerd
Binning and Heinrich Rohrer who shared the
Nobel Prize for physics in 1986 because of the
microscope.
Heinrich Rohrer Gerd Binning
d
Metal tip
Metal slab
Inside the barrier the wave function dies off exponentially:
So the probability of finding an electron after a barrier of width d is:
And:
Where I is the current through the closed circuit.
Tunneling current is proportional to the distance between the tip
and the surface.
How it works
move the tip across the surface, and
using the current as a feedback
signal.
The tip-surface separation is kept
constant by keeping the tunneling
current at a constant value.
The voltage necessary to keep the tip at
a constant separation is used to
produce a computer image of the
surface.