High Resolution Electron Microscopy and Surface Structure Facility
Catalysis Center, B12
Facility Director: Laurence D. Marks, MSE
Visit the High Resolution Electron Microscopy and Surface Structure Facility website here.
This facility provides unique equipment to investigate the atomic scale structure of both the surface and sub-surface region of a sample combined with in situ growth and chemical characterization.
EQUIPMENT:
1. SPEAR: The Specimen Preparation Evaluation Analysis and Reaction System is a system of interconnected Ultrahigh Vacuum (UHV) chambers for the preparation and study of surfaces and interfaces. The Analytical Chamber is equipped with a PHI Electronics Duoplasmatron Ion Gun, a PHI Electronics Dual-Anode X-ray Source, an FEI Thermally Assisted Schottky Field Emission Electron Gun, and the PHI Electronics Spherical Electron Energy Analyzer. The ion gun can produce oxygen, argon, or xenon ions which, when coupled with a secondary electron detector, generate useful Secondary Electron Microscopy (SEM) images during sputtering. The electron energy analyzer can acquire XPS data from either Al K-alpha or Mg K-alpha x-rays from the X-ray source, as well as highly spatially resolved Auger electron data generated by the electron gun. The electron gun can also be used for the direct heating of samples. The Transfer Chamber allows samples to be moved between the Load-Lock, the Analytical chamber, and various other connected systems (UHV-HREM, MIBE, SINBAD) while at all times remaining in a UHV environment.
2. UHV-HREM: The Hitachi UHV-H9000 High Resolution Electron Microscope is the first conventional transmission instrument to achieve routine mid 10 × 10 -11 torr operation. It is equipped with a Gatan Parallel EELS and CCD Camera, both interfaced to computers. Routinely the instrument will resolve at about 0.18nm for bulk spacings and atomic structure of surfaces at about the 0.25nm level.
3. MIBE: The main goal of the Magnetron and Ion Beam Epitaxy System is to combine deposition processes with the analytical capabilities of SPEAR and an UHV TEM. Samples can be grown in MIBE and then transferred to SPEAR where analytical techniques can be performed. It has two metal ion sources currently fitted with boron and carbon targets, two d.c. magnetron sputtering sources used to form ZrN and CNx multilayer materials, and one gas ion source.
4. SINBAD: The Stabilizing Ion and Neutral Beam Assisted Deposition system is a specially designed system for the in-situ investigation of thin solid films. It is designed to handle the deposition of thin films onto thin 3mm TEM ready samples and investigate the effect of energetic particles on materials. The sample manipulation stage can be used for d.c. biasing of the sample as well as resistive heating during deposition and the unit is equipped with a single position electron-beam evaporator, a 4 keV ion-gun, and a compact electron cyclotron resonance (ECR) plasma source. It is also connected to the SPEAR system.
5. Computers: Two Linux clusters, JosephSmith and HyrumSmith, are used for running DFT calculations and compiling code. Additionally, computers are used for image simulation and diffraction calculations. The primary software is NUMIS, a combination of Semper 6 and multislice/imaging programs. Originally these calculations were run on UNIX machines, but are gradually being moved to PC’s running an X-windows environment. Additionally, the EDM software package, which is continually being updated, is used to combine various aspects of image processing and manipulation of high resolution images and diffraction patterns as well as direct methods.