Advanced Materials Characterization Techniques (Analytical)

Explore the development of electron microscopy, distinguishing scanning electron microscopy (sem) and transmission electron microscopy (tem), and how electrons overcome the optical microscope's Abbe diffraction limit for higher resolution.

Understand electron beam interactions in scanning electron microscopy (SEM) that reveal surface topography and composition, including secondary, backscattered, and elastic or inelastic scattering, guided by Kanaya Okayama depth-penetration formula.

Explore the scanning electron microscope (sem) working principle, including electron beam interactions, secondary and backscattered electrons, detectors, and how atomic-number contrast enables material differentiation.

Explore the SEM’s components—from electron gun and magnetic lenses to scanning coils and detectors, including x-ray analysis, and how vacuum and raster scanning yield topography, morphology, and composition.

Explore transmission electron microscopy (tem) instrumentation and working principles, including electron guns, lenses, vacuum systems, ultra-thin specimens, and imaging and diffraction modes.

Compare SEM and TEM reveal that both are electron microscopes offering high-resolution images, but SEM analyzes surface with scattered electrons while TEM transmits through to reveal internal structure.

Explore atomic force microscopy (AFM) and scanning probe techniques, detailing van der waals interactions and Lennard-Jones potentials that govern contact and non-contact modes at atomic resolution.

Explore how AFM uses a sharp cantilever tip to scan surfaces, operating in non-contact and contact modes, and detect features via attractive and repulsive forces, laser deflection, and a photodetector.

Explore how an atomic force microscope creates a 3D topographic map by scanning a sharp tip, measuring cantilever deflection via Hooke's law, and imaging in contact, non-contact, or tapping modes.

Explore the three afm modes—contact, non-contact, and tapping—analyzing probing forces, sample interactions, and advantages over optical microscopy and sem, including operation in liquid.

Discover AFM's capabilities and limits, from nanoscale roughness and mechanical strength measurements to imaging soft biological materials, with speed and field-of-view constraints for large samples.

Explore x-ray photoelectron spectroscopy (xps), which uses monochromatic x-ray photons to eject core electrons and reveal binding energies, chemical states, and surface composition to a depth of 3–10 nanometers.

Explain binding energy as the energy to remove an electron, and how kinetic energy and work function govern photoelectrons and auger electrons in XPS.

Explore XPS instrumentation, from photoelectrons and auger emissions to X-ray sources, monochromators, ultra-high vacuum, extraction lenses, and CMA/CA analyzers with a channel electron multiplier.

Explore how XPS detects electrons ejected from multiple layers, separating top-layer signals from lower-layer noise caused by collisions, and how binding energy shapes characteristic peaks and Auger signals.

Explore how binding-energy shifts reflect an atom's environment, how oxidation state and spin-orbit coupling affect core energies, and the appearance of doublets and satellites in XPS.

Understand final state shake up and shake off effects in XPS, including how core-electron interactions shift binding energies, produce shakeup peaks, and reveal surface composition in thin films.

Explore angle-resolved XPS for surface-focused analysis and depth profiling, using tilted incidence and argon sputtering to reveal surface chemistry and thin-film composition.

Learn Raman spectroscopy and the Raman effect, including Rayleigh scattering, Stokes and anti-Stokes shifts, and how vibrational changes reveal molecular fingerprints.

Compare ir and Raman selection rules to explain why some vibrational modes appear in ir or Raman; dipole moment changes explain ir activity, polarizability changes explain Raman.

Explore the instrumentation of Raman spectroscopy, from laser sources and filters to detectors, and learn how Raman peaks are isolated from the Rayleigh peak for material identification.

Explore electron energy loss spectroscopy and how inelastic scattering of electrons reveals plasmon and interband transitions, with zero loss, low loss, and core loss regions guiding elemental analysis.

Explore surface plasmons as coherent oscillations at interfaces; film thickness relative to the mean free path yields single or multiple peaks, and high energy loss region reveals core loss signals.

Analyze inner shell ionization in eels spectroscopy, identify k and l edges and white lines, assess oxidation states via L3/L2 ratios, and compare with EDS for light elements.

Explore how electron energy loss spectroscopy (eels) analyzes materials from semiconductors to nanomaterials, using zero loss peaks, low loss dielectric properties, and ionization edges for qualitative and quantitative analysis.

Learn how energy dispersive x-ray spectroscopy enables elemental analysis by detecting characteristic x-rays, revealing element identities and concentrations, from micron-scale spots to broad maps, guided by Moseley’s law.

Trace Moseley's law in x-ray spectra, noting k, l, and m series intensities, and explain edx detection with a silicon crystal, collimator, electron trap, cryostat, and MCA.

Explore edx instrumentation, including the pulse processor and multichannel analyzer, and apply energy-dispersive x-ray spectroscopy to identify elements, assess surface contamination, corrosion, coating composition, and rapid material identification.

Explore how x-ray diffraction analysis (XRD) reveals unique patterns from crystalline materials and applies Bragg's law to relate the distance between atomic layers to diffraction angles, in a non-destructive technique.

Explore the x-ray diffractometer architecture, including x-ray tube, collimator, monochromator, sample holder, goniometer, and detectors. Learn fixed and rotating geometry, two theta measurement, and back-reflection and transmission Laue methods.

Explore rotating crystal and powder xrd methods, identifying phases and unit cell dimensions through Bragg diffraction, using monochromatic x rays and two theta scans.

Prepare mineral samples as fine powder for XRD analysis, measure d spacings via Bragg's equation, and identify unknowns by database matching; also explore SAXS and WAXS for nanostructure.

Explore thermogravimetric analysis (TGA), a method that measures mass change during heating to study decomposition, oxidation, and dehydration. Learn isothermal, quasi-static, and dynamic TGA and the role of environments.

Explore the core components of a TGA, including sample holder, furnace, purge gas inlet, thermocouple, and microbalance. Compare null and deflection balance principles, temperature control, atmosphere, and rapid heating.

Explore tga instrumentation, purge gas, thermocouple placement, and recorder types, and learn how heating rate, atmosphere, and sample size influence the weight loss curve and applications.

Prepare a small sample (5–20 mg), calibrate the TGA with reference materials, and run a baseline-corrected heating to measure weight loss, then analyze decomposition temperature, kinetics, and DSC/DTA as complements.

Explore differential thermal analysis (DTA) by measuring delta T between a heated sample and an inert reference to identify endothermic and exothermic events.

Differential thermal analysis (DTA) uses paired thermocouples and a controlled furnace to measure sample–reference temperature differences, producing thermograms that show phase transitions and reactions.