Nanometres‐resolution Kikuchi patterns from materials science specimens with transmission electron forward scatter diffraction in the scanning electron microscope

Abstract

Summary A charge‐coupled device camera of an electron backscattered diffraction system in a scanning electron microscope was positioned below a thin specimen and transmission Kikuchi patterns were collected. Contrary to electron backscattered diffraction, transmission electron forward scatter diffraction provides phase identification and orientation mapping at the nanoscale. The minimum Pd particle size for which a Kikuchi diffraction pattern was detected and indexed reliably was 5.6 nm. An orientation mapping resolution of 5 nm was measured at 30 kV. The resolution obtained with transmission electron forward scatter diffraction was of the same order of magnitude than that reported in electron nanodiffraction in the transmission electron microscope. An energy dispersive spectrometer X‐ray map and a transmission electron forward scatter diffraction orientation map were acquired simultaneously. The high‐resolution chemical, phase and orientation maps provided at once information on the chemical form, orientation and coherency of precipitates in an aluminium–lithium 2099 alloy.

A method to correct coordinate distortion in EBSD maps

“…Besides, the recently developed t-EBSD (or TKD) techniques [11][12][13] allows orientation mapping on TEM foils in the transmission mode, which provides more possibilities in using EBSD in combination with TEM. As the t-EBSD techniques are most suitable for nanostructured materials, it is expected that TEM images of nanostructures may be used as reference images in the future.…”

“…However, if small electron beam step sizes such as 20-30nm, or even 2-5nm used in the transmission mode (i.e. the so-called t-EBSD or TKD (transmission Kikuchi diffraction) [11][12][13]) are utilized, the drift-induced coordinate distortion can significantly affect the data because the drift speed is comparable to the step sizes (see Table 1). This problem has been widely recognized, and is solved generally either by cutting off the initial part of the EBSD map, thus excluding the most distorted part from the analysis, or by starting EBSD measurements when there is no significant drift, i.e.…”

A novel quantum dynamical approach in electron microscopy combining wave-packet propagation with Bohmian trajectories

“…However, they are still present in Fresnel diffraction and can provide information about the material. Higher tilt angles may be used in experiments such as transmission electron forward scattering diffraction (t-EFSD) where Kikuchi patterns can be imaged [44]. Here, any tilt angle can be simulated by rotating the initial wave packet and attributing the appropriate momenta to both spatial components.…”

Imaging with a Commercial Electron Backscatter Diffraction (EBSD) Camera in a Scanning Electron Microscope: A Review

“…The accelerating voltage was 30 kV. Note that the homemade sample holder used for this work allowed us to collect BF-STEM images and transmission EBSD (t-EBSD) data without any change of geometry or detector position, as described in a previous paper [21,22].…”