attoAFM /STM
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attoAFM/STM
combined low temperature atomic force and scanning tunneling microscope
In the attoAFM/STM, the two worlds of atomic force and scanning tunneling microscopy are genuinely combined. In contrast to the attoAFM
III, the attoAFM/STM uses a horizontally aligned tuning fork to reduce
unshielded tunneling current wire lenght to a minimum (several millimeters in this case).
The attoAFM/STM is available with interferometric encoder for closed
loop operation.
Principle - The attoAFM/STM typically uses an ultra-sharp etched tungsten tip as a probe. The tip is glued onto the tuning fork and electrically connected to a current/voltage amplifier located on the top of the
experiment. A low temperature, high-vacuum compatible coaxial cable
is used for this connection, guaranteeing minimum possible noise
pickup. The instrument can be operated in AFM, STM, or combined AFM
& STM mode.
With this instrument, scanning tunneling spectroscopy measurements
on generally non-conductive samples with conductive patches have
finally become possible. One of the biggest advantages of this design
is the large scan range at low temperatures of 9 µm x 9 µm x 2 µm. This
is almost two orders of magnitude larger in area than in conventional
STM designs. This way, lithographically defined mesoscopic nanostructures, be it conducting or insulating, can be located and investigated.
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2
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01 LT and HV compatible feedthroughs
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02 vacuum window
03 microscope insert
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04 superconducting magnet (optional)
05 liquid He dewar (optional)
06 ultra stable Titanium housing
07 xyz coarse positioners
08 xyz scanner
09 quick-exchange sample holder
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Schematic drawing of the low temperature
attoAFM III and the surrounding liquid
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helium dewar (optional)
10 tuning fork AFM/STM sensor