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A high-angle tilt grain boundary viewed end-on in a (011) thin crystal of Ge has been imaged with atomic resolution in the Kyoto 500 kV electron microscope. The boundary is shown to consist of alternating columns of five- and seven-membered rings of Ge atoms running along the [011] direction, and to contain no dangling bonds.
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Krivanek et al. (1977) studied this question.
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