Precession Electron Diffraction (PED) and Differential Phase Contrast (DPC) help reveal the nanoscale structural and electrostatic features that often control whether a material performs as expected. In this case study, Covalent shows how these advanced TEM/STEM-based techniques were used to solve three very different client challenges. In a GaN/AlGaN device stack, PED mapped local strain while DPC visualized the electric-field response, helping connect microstructure to device behavior. In NMC battery materials, PED measured grain size, crystal orientation, and grain-boundary networks at the nanoscale, providing insight into performance variability and degradation risk. In an amorphous material system, PED-assisted electron pair distribution function (e-PDF) analysis uncovered short-range atomic ordering that conventional bulk methods would miss. Together, these examples show how PED and DPC can move analysis beyond basic imaging to reveal the structural fingerprints behind drift, variability, and reliability issues. The result is clearer root-cause insight, better process decisions, and more confidence in material and device performance.
PED and DPC in the TEM: Mapping Strain, Orientation and Electric Fields at the Nanoscale
Strain, grain orientation and internal electric fields often explain why a material or device doesn’t perform as expected, but standard TEM imaging can’t show them. In this case study, we used precession electron diffraction (PED) and differential phase contrast (DPC) in the STEM to map strain and electric fields in a GaN/AlGaN device stack, measure grain size and orientation in NMC battery cathode material, and detect short-range atomic order in an amorphous film.