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GPI STMs is a series of ultrahigh vacuum scanning
tunneling microscopes, designed for in situ surface processes study with
atomic resolution. The following principles are in a basis of a design
of the device:
-
It
should work in a combination to standard methods of the surface analysis
and preparation in ultrahigh vacuum
- The open access to a surface of a sample for influence by electrons,
ions, photons, atoms and molecules should be provided while scanning.
- Control electronics, vacuum module, sample and tip transfer system,
arrester, wiring and other support components should remain the same
for any type of STM head, including variable temperature or spin-polarised
STMs
GPI-300 is a room temperature ultrahigh vacuum scanning
tunneling microscope. It can be used for study of any surface processes
at room temperature in vivo. Areas of application:
- chemical and photochemical reactions, heterogeneous catalysis
- coating and epitaxy
- semiconductor technologies
- adsorption
- modification of a surface by ions, electrons and other particles
- nanotechnology, single-atom manipulations
GPI-300 was developed in General Physics Institute (GPI)
of the Russian Academy of Sciences in 1994 and since that time it has
been successfully employed in the Surface Phenomena Laboratory at GPI.
The main objects of studies are the reaction of chlorination of metals
and semiconductors, carbon nanotubes material and radiation defect behaviour
on a surface of graphite.
The
original STM design described in [K.N.Eltsov, A.N.Klimov, S.L.Priadrin,
V.M.Shevlyuga, V.Yu.Yurov, Phys. Low-Dim. Struct. 7/8 (1996) 115] was
taken as a basis for the commercial device GPI-300. The scanner
consists of three piezo-ceramics tubes, fixed in one line on a surface
of a massive copper platform. Every tube has four outside and one internal
metal electrodes, that allows to carry out positioning of the free end
of the tube in three coordinates X, Y, Z. The tip holder is mounted on
the left piezo-tube, and the sample holder is fixed to a special quartz
slider that lies on four sapphire balls on the top of two others tubes.
The sample and tip transfer from a linear manipulator into the STM is
carried out by the XYZ-manipulator. After positioning to a distance of
2-3 mm the tip and the sample could be easily closed in to a distance
of a tunnel gap (5-10 A) by piezo-inertial movement realized by means
of two piezo-tubes: quartz slider with a sample slips on sapphire balls.
Direction and the speed of movement is adjusted by the special generator,
controlled by a computer. Such a movement is in Z- and X- directions with
speed up to 2 mm/min with accuracy of positioning up to 5 nm.
The platform with the scanner is suspended on long
springs as the main step of vibroisolation system, the other step is small
viton columns, separating suspending system and a case of the vacuum chamber.
Electrical feed-throughs for input/output signals are mounted on DN40-CF
flanges of the nipple. The control and signal wires, that pass separately
through metal tubes of a support frame, are distributed on a circle of
the bottom motionless ring and then, are connected to the scanner by springs.
Samples and tips transfer occurs at an arrested position of the scanner
on motionless support on the bottom ring. For this purpose the arresting
system, including standard rotary feed-through (DN40-CF or DN16-CF) is
used.
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