Gerd Binning and Heinrich Rohrer developed the
scanning tunneling microscope in 1981,presumably because they found viewing
through standard microscopes ‘uncool’ An older version of the STM was the
‘topografiner’ invented by Russel Young and his colleagues between 1965 and
1971.
A super fine tip is taken and kept at a distance of
one nano meter away from the sample. The tip is changed and hence electrons
start flowing from the tip to the surface in a process called ‘tunneling’. The
current flowing through the tip is kept constant by scanning the tip over the
surface horizontally and by adjusting the height of the tip vertically. This
results in a 3-D image of the surface, which in our opinion is pretty damn cool.
Because of the 3-D structure, one could make characterize surface roughness,
observe surface defects, and determine the size and conformation of molecules
and aggregates on the surface.
STMs are also advantageous because they can be used
in ultra-high vacuum, air, water, other gases, as well as foam temperatures as
low as 273 degree Celsius to around 300 degree Celsius. Their only drawback is
that they require quite a bit of skill to use and are very fragile so forget
running and buying one for yourself. Also, it costs only about $8000 for the
cheapest STM.
