This page provides information about and various photographs of our UHV STM system. Click on the desired photo to view an larger version.
| Here are three perspectives of our system. It is isolated on
self-regulated air-legs, with additional weight suspended from the
underneath to improve the vibrational isolation. The heart of the system
is a Burleigh Instruments Aris 5000
UHV-compatible
STM,
consisting of an inchworm motor for coarse approach and a piezoelectric x-,
y- and z- scanner at the end of the motor. The motor scanner is
mounted on an Invar plate and employs a vibration isolation system of four
Iconel™ springs and four eddy current damping magnet assemblies.
The UHV STM chamber includes three angled 2-¾ inch ports on top which are aimed precisely at the center of the quartz STM holder when it is parked in the STM heater stage. One of these ports is fitted with a residual gas analyzer (RGA) to monitor the gasses that evolve from the sample while the sample is heated and is also used to monitor vacuum quality and leak checking. Another port is fitted with an ion sputter gun to allow ion sputter cleaning and annealing, a useful technique for cleaning certain materials in UHV. The third port is used for deposition of materials during evaporation. The main UHV chamber is equipped with a 400 liter per second ion pump, which can maintain a vacuum below 10-10 Torr, and a titanium sublimation pump for added pumping during times of high gas load. An Omicron™ Auger system, consisting of a cylindrical mirror analyzer (CMA) and coaxial electron gun, is attached to the top 6" port. The system is also equipped with several Varian™ leak valves for accurate gas dosing. A low-energy electron diffraction (LEED) system is attached to an 8" port. A UHV-compatible hot-tungsten filament chemical vapor deposition (CVD) diamond growth system is attached to the UHV chamber via an all-metal through valve. Samples are transferred from the CVD chamber to the UHV STM chamber using linear translators without contaminating the samples by exposure to air. To see a schematic of our system, click here (12 kb). |
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The figure to the left shows the main chamber of our UHV STM, as seen through the viewing port. To the right is an expanded view. In the lower left of the chamber is the inchworm, which controls the motion of the small wire tip protruding from the right end of the inchworm. To the right of the inchworm is the base for the sample holder, which secures a quartz base to which the sample is attached. The springs serve as part of the isolation system, to isolate the tip/sample system from external vibrations. |
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The left image shows the main chamber of the UHV STM with a sample in the heating stage, while the right image provides a magnified view. The heated sample (glowing red) is easily seen. |
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