Accuracy and precision of thickness determination from position-averaged convergent beam electron diffraction patterns using a single-parameter metric

A deep convolutional neural network to analyze position averaged convergent beam electron diffraction patterns

“…The localized region of network activation and response of 19.1 mrad is attributed to the reduction of pattern features when the convergence semi-angle is large. As a result, the 19.1 mrad CNN trained for determining thickness cannot handle thicker sample measurement, which has also been reported for LSF methods [10]. In order to reduce the complexity of the network, the acceptable thickness range is reduced to 1-80 nm for SrTiO 3 , which improves the network reliability (87-92.3%) when compared to LSF.…”

“…To reduce human error and enhance the repeatability of the measurements, a semi-automated approach is usually employed. To this end, least square fitting (LSF) has been the primary tool [3,4,[8][9][10]. The parameter of interest, e.g.…”

“…While LSF can precise and accurate [10], it can be time-consuming to avoid local minima during the search across a broad range of parameters. Beyond processing speed, patterns alignment is an additional limiting factor.…”

Quantifying Jahn-Teller distortion at the nanoscale with picometer accuracy using position averaged convergent beam electron diffraction

“…By comparing the experimental pattern to simulated ones, the thickness of the specimen in the electron beam direction was measured to be 31.0 ± 0.7 nm using the PACBED shown in Fig. 1(b) [32]. A slight specimen tilt of 0.5 mrad is observed and measured using the distance between the whole pattern center of mass and the center of the transmitted disk.…”

“…By incoherently averaging diffraction patterns formed by rastering an atomicscale probe across one or more unit cells, a wealth of information is encoded in the intensity distribution around the zero-order disk. By pattern-matching algorithms, PACBED has been used to investigate specimen properties such as thickness [32,33], tilting of octahedra [29], and polarization [34]. In this article, single-crystal LaMnO 3 is selected to investigate intensity distribution changes in PACBED patterns caused by JTD, and the resultant structural parameters are compared with results from multiple complementary methods [20].…”