Materials Characterization Technique Selection

Think about: What type of magnification do I need? Do I need to image the surface or bulk structure?

Optical microscopy allows sample surface imaging from 1x - 5000x magnification. This is typically the first step in any imaging project.

• The stereo-microscope allows fast sample surface imaging from 1x - 65x with video capture and image processing. It's a good idea to use this before trying other methods.

• The inverted stereomicroscope allows fast stample imaging of large opaque or live cell samples from 10x - 100x with video capture and image processing.

• The Hirox Digital Microscope can provide 2D and 3D surface images, as well as videos, from 1x - 5000x magnification. The Hirox can also be used for measurements of surface roughness and feature length, height, and volume.

Scanning electron microscopy (SEM) provides sample surface imaging down to the nanoscale, from 6x to 500,000x magnification.

• The Quanta 200 LV SEM allows imaging of conductive sample surfaces (or coated samples) to magnifications from 50x to 100,000x, as well as microprobe elemental analysis and mapping for Z > 4 amu (EDS). The Quanta 200 can operate in high & low vacuum modes, as well as ESEM.

• The Quanta 650 SEM allows imaging of conductive sample surfaces (or coated samples) to magnifications as large as 500,000x, as well as microprobe elemental analysis and mapping for Z > 4 amu (EDS). Mapping of grain orientations, texture and phase analysis can be done with the complementary EBSD system. The Quanta 650 can operate in high & low vacuum modes, as well as ESEM.

Scanning transmission electron microscopy (HRTEM-STEM) provides sample imaging from the nanoscale to the atomic scale at > 1,750,000x magnification.

• The Titan 80-300 HRTEM Transmission Electron Microscope (HRTEM-STEM) provides imaging on the atom scale with resolution better than < 0.2 nm for thin samples (< 200 nm). Magnifications are to > 5,000,000x. Crystal structures and atomic arrangements can be identified through imaging and diffraction, in combination with EDS for elemental analysis and mapping for Z > 4 amu.

• The new Themis Transmission Electron Microscope (HRTEM-STEM) provides atomic atomic resolution imaging of crystal lattices and imaging of defects, precipitates and interfaces using bright- and dark-field techniques, as well as diffraction techniques and elemental analysis using EDS and Electron Energy Loss Spectroscopy (EELS). Image resolution is better than < 0.1 nm for thin samples (< 50 nm). Magnifications are to > 10,000,000x.

X-ray Computed Micro-Tomography (micro-XCT) for micro-scale imaging a sample’s 3D internal structure with spatial resolution of around 1 um.

• The Xradia MicroXCT-200 reconstructs a sample’s 3D internal structure by measuring the X-ray transmission from multiple perspectives with up to 1 µm resolution, depending on sample size and composition, to provides information about internal structure, cracking, and changes in density.

Think about: Am I interested in the bulk or surface composition? What spatial resolution do I need? What sensitivity?

Energy-dispersive X-ray fluorescence spectroscopy (XRF) provides high sensitivity (1ppm) quantitative elemental compositional information for Z > 10 in bulk materials with an information depth to 2 um - 2 mm depending on the sample. Our instrument illuminates entire sample (~28 mm diameter) and has no mapping capabilities.

• The Panalytical Epsilon 3x Energy-Dispersive XRF spectrometer allows non‐destructive identification and quantification (1 ppm) of elements from sodium (Na) to americium (Am) in solids, liquids, loose‐ and pressed‐powders.  Omnian standardless analysis software for peak ID and quantification.

X-ray photoelectron spectroscopy (XPS) provides quantitative elemental compositional information for Z > 2 for surfaces of solids with an information depth of 1 - 10 nm. An ion sputter gun allows depth profiling to > 5 um for 3D compositional analysis into the bulk material. Point and large area analysis, as well as maps, can be acquired with 1) a spatial resolution of 9 um and 2) a sensitivity of 100 ppm.

• The PHI Versaprobe III XPS provides non‐destructive identification and quantification (100 ppm) of solids, thin-films, and powder surfaces (1 - 10 nm) for elements with Z ≥ 3. Small-spot (9-200 micron) and large-area analyses (mm-scale) available, as well as elemental and chemical mapping. An ion sputter gun allows depth profiling to > 5 um for 3D compositional analysis through oxides, interfaces, and into the bulk material.

Scanning electron microscopy (SEM) provides quantitative elemental compositional information using Energy-Dispersive X-ray Analysis (EDS/EDX) for Z> 4 with 1) a spatial resolution of 10 nm, 2) an information depth of 1 - 5 um, and 3) a sensitivity of 1000 ppm.

• The Quanta 200 LV SEM allows elemental point analysis and mapping of conductive sample surfaces (or coated samples) for Z > 4 amu (EDS). The Quanta 200 can operate in high & low vacuum modes, as well as ESEM.

• The Quanta 650 SEM allows elemental point analysis and mapping of conductive sample surfaces (or coated samples) for Z > 4 amu (EDS). The Quanta 650 can operate in high & low vacuum modes, as well as ESEM.

Scanning transmission electron microscopy (HR-STEM) provides quantitative elemental compositional information using Energy-Dispersive X-ray Analysis (EDS/EDX) for Z> 4 on thin samples with 1) a spatial resolution of 1nm, 2) an information depth of ~100 nm (generally through thickness of sample), and 3) a sensitivity of 1000 ppm. Electron Energy Loss Spectroscopy (EELS) can provide compositional information for low-Z elements (Z > 2).

• The FEI Titan Transmission Electron Microscope (HR-STEM) provides elemental point analysis and mapping of thin conductive samples for Z > 4 amu (EDS).

• The new FEI Themis Transmission Electron Microscope (HR-STEM) provides elemental point analysis and mapping of sample for Z > 4 amu (Super X EDS). EELS can be used for elemental, and in some cases chemical, point analysis and mapping for Z> 2. Energy-filtered TEM allows for mapping of individual elements in a sample.

Think about: Am I interested in the bulk or surface chemistry? Is my sample crystalline or amorphous? What spatial resolution do I need? What sensitivity?

X-ray photoelectron spectroscopy (XPS) provides quantitative chemical compositional information for Z > 2 for both crystalline and amorphous solid surfaces with an information depth of 1-10 nm. An ion sputter gun allows depth profiling to > 5 um for 3D analysis into the bulk material. Point and large area analysis, as well as chemical maps, can be acquired with 1) a probe spot of 9 um and 2) a sensitivity of 100 ppm.

• The PHI Versaprobe III XPS provides non‐destructive identification and quantification (100 ppm) of chemical bonding between atoms on surfaces (1 - 10 nm) for elements with Z ≥ 3. Small-spot (9-200 micron) and large-area analyses (mm-scale) available, as well as elemental and chemical mapping. An ion sputter gun allows depth profiling to > 5 um for 3D compositional analysis through oxides, interfaces, and into the bulk material.

Raman Spectroscopy (Raman Analysis) allows the determination of sample chemistry and the identification of molecular compounds with vibrational bands between 100 - 4000 cm-1 on solid materials (either crystalline or amorphous). Points and maps can be collected with 1))  < 2 micron spatial resolution, 2) a sensitivity of  < 1000 ppm and an information to a depth of 1 um. Tip-Enhanced Raman spectroscopy (TERS) for enhanced surface specificity (~10nm) is also available.

• The Renishaw InVia™ Confocal Raman microscope provides non‐destructive identification and quantification (1000 ppm) of the chemistry and  molecular bonding between atoms in materials (to a depth of 1um). Both small-spot (~1 micron) analysis and maps can be acquired, selecting one of four possible wavelengths, for molecular vibrational information of hydrocarbons, water, polymers, amines, minerals, etc.

Electron Energy Loss Spectroscopy (EELS) provide compositional information for low-Z elements (Z > 2), and additionally yields data on chemical bonding and nearest neighbor distances for most elements.

• The new FEI Themis Transmission Electron Microscope (HRTEM-STEM) provides chemical bonding information down to the sub nanometer scale for most elements in thin samples <100 nm thickness.

X-ray Diffraction (XRD) is a nondestructive tool to provide bulk material chemical information by the identification of phases for crystalline powders and solids, where the crystallite size is greater than 5 nm. Optics can be customized to provide a spot size of less than 150 microns to several more than 25 mm. Sample sizes can be as little as a few mg of powder or tens of microns of film depth, or as big as a block several inches in length width and depth. Sampling depth (typically 20 nm - 2 mm) is highly dependent on material composition and X-ray incidence angle. XRD has a sensitivity of < 1% (atomic percent).

• Multiple XRD diffractometers are available for analysis of crystalline and polycrystalline materials (amorphous structures provide no pattern) within the NMCF, including the Panalytical Empyrean, the Panalytical 'Xpert Pro, and the Rigaku SmartLab instruments. Multiple sample stages to accommodate various sizes and types of samples are available, including a non-ambient chamber for high-temperature in situ measurements.

Think about: Am I interested in bulk crystallography or local atomic arrangement? Is my sample size large or small? Do I need surface-specific crystallography?

X-ray Diffraction (XRD) is a nondestructive tool to provide bulk material identification of phases for crystalline powders and solids, where the crystallite size is greater than 5nm. Optics can be customized to provide a spot size of less than 150 microns to more than 25 mm. XRD has an information depth of 100 um - 2 mm, and a sensitivity of < 1% (atomic percent). Sample sizes can be as little as a few mg of powder or tens of microns of film depth, or as big as a block several inches in length width and depth. Data can be taken in ambient conditions, vacuum, and/or varied thermal regimes. 

• Multiple XRD diffractometers are available for analysis of crystalline and polycrystalline materials (amorphous structures provide no pattern) within the NMCF, including the Panalytical Empyrean, the Panalytical 'Xpert Pro, and the Rigaku SmartLab instruments.Sampling depth (roughly between ~2 nm to ~30 µm) is highly dependent on material composition and X-ray incidence angle. Multiple sample stages to accommodate various sizes and types of samples are available, including a non-ambient chamber for high-temperature in situ measurements. XRD requires very little sample preparation and is an excellent method for determination of bulk material crystallography.

Scanning electron microscopy (SEM) provides small area ( < 100 nm) crystal structure and phase, grain orientation mapping, and strain information with an Electron Back-Scatter Detector (EBSD). Selection of low-energy incident electrons provides surface-specific crystallography. EBSD enables crystallography with 1) a spatial resolution of <100nm and 2) a selectable information depth of nm - um. Not used for amorphous materials. Requires sample admission to vacuum. Data can be taken at varied temperature.

• The Quanta 650 SEM provides spatially-resolved structure and phase analysis via EBSD by point analysis and mapping. Samples must be conductive or C/Au/Pt -coated. The Quanta 650 can operate in high & low vacuum modes, as well as ESEM.

• The Helios FIB/SEM provides spatially-resolved structure and phase analysis via EBSD by point analysis and mapping. Samples must be conductive or C/Au/Pt -coated. The Helios operates under high vacuum.

Scanning transmission electron microscopy (HR-STEM) enables nanoscale or atomic-scale images of thin sections of a material, where high-energy electrons pass through the sample to form the image or provide crystal structure information, including phase. STEM has 1) a spatial resolution of  < 1nm, 2) an information depth of < 1um (generally through thickness of sample), and 3) a sensitivity of 1000ppm. Electron diffraction for structural analysis of areas with diameters > 170 nm

• The arrangement of atoms can be directly imaged with the FEI Titan Transmission Electron Microscope (HRTEM-STEM). Samples must be appropriate for high-vacuum and require significant preparation prior to analysis.Electron diffraction yields data on crystal structures.

• The arrangement of atoms can be directly imaged with the FEI Themis Transmission Electron Microscope (HRTEM-STEM). Samples must be appropriate for high-vacuum and require significant preparation prior to analysis. Electron diffraction yields data on crystal structures.

Think about: What is the depth-scale of the roughness? What spatial resolution is required?

The Bruker Innova AFM (atomic force microscope) measures the smallest surface-height differences and is able to image atomic-scale roughness. AFM provides non-destructive characterization of surface roughness with a resolution of < 0.1 nm via contact or tapping mode over an area up to 250um  x 250 um x 100 um. Spatial resolution > 2 nm.

• The Bruker Inova AFM provides atomic resolution roughness analysis with atomic resolution. Samples may be analyzed in air or in liquid. Users should bring their own tips. AFM scans have better resolution, but are more time-consuming than optical methods.

The Zygo white-light optical profilometer has ~ 1nm resolution and is specifically utilized for determination of surface topography and measurement of surface shape, surface finish, surface profile roughness (Ra), or in surface area roughness (Sa), surface texture, asperity and structural characterization.

• The Zygo profilometer provides a nondestructive, Interferometric method for area and height measurement with a depth resolution of  < 1nm +/- < 0.1nm and a lateral resolution of 360 nm. Information can be acquired over a field of view: 0.03 to 14 mm. Also measures thin film thickness.

Optical measurements and models of surface roughness can be made with the Hirox Digital Light Microscope with minimal sample preparation and in a short amount of time. Roughness of > 20 nm can be determined.

• The Hirox Digital Microscope  provides 2D and 3D surface images, as well as videos, from 1x - 5000x magnification, and can  be used for measurements of surface cross-sectional roughness (Ra, Rz, Rzjis) and feature length, height, and volume. Good for measurements on steep flanks and very rough surfaces.

Scanning electron microscopy (SEM) provides sample surface imaging down to the nanoscale, from 6x to 500,000x magnification for roughness determination and measurement.

• The Quanta 200 LV SEM allows imaging of conductive sample surfaces (ESEM or coated samples) to magnifications from 50x to 100,000x. Quanta 200 can operate in high & low vacuum modes, as well as ESEM.

• The Quanta 650 SEM allows imaging of conductive sample surfaces (ESEM or coated samples) to magnifications as large as 500,000x. The Quanta 650 can operate in high & low vacuum modes, as well as ESEM.

• The Helios G4 UC Dual Beam FIB/SEM allows imaging of conductive sample surfaces (or coated samples) and can perform 3D slice and view with quantitative 3D imaging and visualization with software tools for height and  roughness measurement.

Think about: How hard is my material? At what point does it fracture?

• Rockwell Hardness Testing ( Wilson Model 4 ) is the most commonly used hardness tester and can be used with all metals, based on choice of scale. This indentation method of hardness testing is used for most parts, except thin materials. Forces are typically 3 kg - 150kg. 

• Vickers Hardness Testing, also referred to as the microhardness test method, is an indentation method mostly used for small parts and thin sections. NMCF has a Bühler Micromet 5101 Vickers hardness tester with camera and set-up for Knoop testing for very thin materials. Forces are typically 10 - 1,000g.