The IEN/IMat Materials Characterization Facility (MCF) is the core facility for materials analysis at Georgia Tech. Its laboratories include the recently-opened microanalysis suite in the Marcus Nanotechnology Building, one of the most advanced facilities of its kind in the nation. Read More
Available to academic, industry, and government users, the MCF at Georgia Tech is a merger of several labs on campus under one umbrella with a uniform set of fees and policies. The MCF offers a wide variety of microscopy and characterization tools as well as skilled research staff to support your research needs.
MCF offers shared-user access to the latest in imaging and analysis technology, which can be accessed by users 24 hours a day. It also provides a full contingent of services for researchers including,
- Equipment training
- Remote sample prep and measurement
- Imaging and analysis consultations"
The Tools in the MCF
The diverse tools in the MCF can be sorted by their ability to do one or more of these three basic measurement techniques:
- Microscopy – magnifying the physical features of a sample up to 10 million times to determine feature sizes, shapes and structure
- Spectroscopy – sorting the particles or radiation emitted from a sample by energy or mass, usually to determine its composition, and
- Diffraction – sorting the particles or radiation emitted from a sample by position or direction usually to determine its structure
- Electron Microscopy(SEM, (S)TEM, FIB-SEM):Electron microscopes are divided into two main types – Scanning Electron Microscopes (SEM’s) and Transmission Electron Microscopes (TEM’s).
- Scanning Probe Microscopy(AFM, STM, nanoindentation): Another method of imaging samples involves moving a sharp probe across the surface of a sample. By measuring and amplifying its deviations as it tracks the surface features, it is possible to build a three-dimensional image detailed enough to measure the size of individual atoms. This family of techniques is called Scanning Probe Microscopy (SPM).
- EM-based Spectroscopy(EDS, EELS): Many electron microscopes – including 7 of the SEM’s and TEM’s in the MCF – are equipped with Energy Dispersive X-ray Spectroscopy (EDS or EDX) detectors. This technique analyzes X-rays generated when the high-energy electron beam hits the sample. These X-rays have unique, characteristic energies that allow them to be matched to the element that generated them. By this technique, it is possible to construct maps of how elements are distributed within a sample, and determine the absolute composition of a sample within ~1%. EDS data only yields absolute composition ratios, and does not provide chemical state information.
- Surface Science Spectroscopy(XPS, UPS, ToF-SIMS): Surface-science tools are typically high vacuum or Ultra-High Vacuum (UHV) systems. The high vacuum level works to keep the sample surfaces pristine. As the name indicates, these tools analyze only the outermost molecular layers of a material, – typically ~5 nm or less – use photon or particle beams to excite a sample, and generally measure particles ejected by the excitation source.
- Optical Spectroscopy(Raman, FTIR): Visible light provides most people with the majority of their information about the world. In spectroscopy there are several techniques that make use of that same general spectral band to measure chemistry and structure.
- X-Ray Diffraction(XRD): X-ray diffraction is a technique that utilizes an incident x-ray beam to identify the structural properties of a sample. When the x-rays interact with the atoms of the sample, the beam is re-radiated into specific directions where there is constructive interference – i.e., diffracted – with characteristic intensities. This set of diffracted x-rays forms a three-dimensional map of the electron density. Analyzing the regular relationships in the diffraction pattern gives information to precisely determine the structure and spacing of the atomic lattice of the sample.
Sample prep capabilities
MCF staff can assist users in preparing samples for any of the above techniques. The following techniques are available:
- carbon evaporation (Cressington 108A carbon coater, Quorum Q-150 T ES)
- gold / palladium sputter coating (60:40 Au/Pd alloy; Hummer V sputter coater system)
- UV / ozone cleaning (SEM: Hitachi ZoneSEM)
- UV/ ozone cleaning (TEM: Hitachi ZoneTEM)
- vacuum oven (drying / driving off solvent)
- IR heat lamp (sample outgassing / adhesive curing)
MCF provides some types of SEM sample stubs and adhesive materials (e.g. carbon dots, carbon tape, copper tape, colloidal graphite / carbon paint, silver paint, high-temperature nickel paste, etc).