Energy-filtered 4D STEM reveals short-range ordering motifs in semiconductors

Gatan instruments used

GIF Continuum^® K3^®, STEMx^®, and eaSI™ technology

Background

Modern semiconductors often incorporate a dilute mixture of elements to fine-tune their electronic properties. However, the atomic arrangement of these mixed elements remains poorly understood, and models suggest that this arrangement can significantly impact key properties, such as the band gap. Electron diffraction readily reveals the long-range order of the crystal, but the local distribution of dilute atoms is encoded in the scattering pattern as weak elastic diffuse scattering between the strong crystal peaks. Unfortunately, inelastic scattering events (e.g., plasmon excitations) also appear in the same region of the scattering distribution and are much stronger than the elastic diffuse signal, effectively masking it. Using an energy filter removes the inelastic scattering, enabling accurate measurement of the elastic diffuse scattering.