{'fraction_non_alphanumeric': 0.047976011994003, 'fraction_numerical': 0.0007496251874062968, 'mean_word_length': 5.708542713567839, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Large-Collection-Angle BF STEM Imaging of Compound Semiconductors

The aberration-corrected scanning transmission electron microscopy (AC-STEM) is a powerful and versatile instrument, which can be equipped with a multitude of detectors including high-angle annulardark-field (HAADF), medium-angle annular-dark-field (MAADF), bright-field (BF), annular-brightfield (ABF), secondary electron (SE), and back-scattered (BSE), as well as energy-dispersive x-ray spectrometer (EDS) and electron-energy-loss spectrometer (EELS). Because HAADF STEM is an incoherent imaging mode with high atomic-number sensitivity (“Z-contrast”), and because it can be easily combined with EELS, it is most often utilized. However, modern AC STEMs can acquire multiple images from different detectors simultaneously, and these other imaging modes can also provide valuable materials information. Because each mode can be considered as complementary, the acquisition of several images allows better understanding and interpretation of materials microstructure. Phase contrast dominates in BF imaging when a small collection angle is used, as implied by the reciprocity theorem. However, when the collection angle is increased to be as large as the convergence semi-angle, phase contrast is suppressed and incoherent contributions dominate image formation [1].