LIBRA
The 200kV Zeiss monochromated LIBRA 200MC is designed to produce high contrast imaging for TEM and STEM and either convergent beam or parallel beam diffraction using Koehler illumination.In addition, the incorporation of a monochromator into the field emission gun enables energy resolution of ~0.15eV for electron energy loss spectroscopy. The dedicated in-column Omega Filter implemented in this microscope also can be used for both spectroscopic analysis and energy-filtered imaging with a 2048x2048 CCD camera. The high tilt capability of the stage and pole piece accepts various types of analytical holders.This microscope is optimized for soft materials applications that require either the high contrast imaging performance or analytical methods such as EF-TEM and STEM.( Instrument Schedule & Requirements: 12-9am, 9-6pm, 6-12am; 1 session at a time during normal weekday business hours.)
Contacts: Andrew Minor or Zonghoon Lee
Specifications
| Resolution | |
| Point-to-Point | 0.29 nm |
| Information limit | 0.19 nm |
| Energy resolution | 0.7 eV without monochromator |
| 0.15 eV with monochromator | |
| STEM Spatial Resolution | |
| BF/DF | 0.45 nm |
| HAADF (attainable) | 0.45 nm |
| Electron Emitter |
| Emitter ZrO/W-field emitter system (Schottky) |
| Accelerating voltage 200 kV |
| Illumination system |
Parallel wide field TEM mode 0.1 urad to 20 mrad illumination aperture |
| Objective lens: HT objective | |
| Cs (Spherical aberration) | 2.2 mm |
| Cc (Chromatic aberration) | 2.2 mm |
| Specimen stage | |
| Double tilt holder tilt | angle ±70 deg / ±30 deg |
| Cryo-double tilt holder | angle ±49 deg / ±30 deg |
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Direct strain measurement in a 65 nm node strained silicon transistor by convergent-beam electron diffraction with and without filter. |
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EFTEM image series of BN nanoparticles and carbon nanotubes on lacy carbon grid. Click on image to see a through energy movie. |
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Conventional (unfiltered) and elastic (zero-loss filtered) convergent beam electron diffraction (CBED) patterns from Si (110). The inelastic scattering component in the unfiltered pattern is clearly removed by zero-loss filtering. |
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A monochromated electron energy-loss spectrum from a NiO thin film (bottom). The spectrum was recorded on the CCD camera mounted under the viewing chamber. The recorded spectrum is also shown (top). The omega filter provides a double-focused spectrum at energy-dispersive plane, which create a spectrum line instead of a spectrum band. By using the monochromator, detailed features around the Oxygen K and Ni L2,3 edges can be seen clearly. |
