Structural Transformations of the Dislocation Cores in Si and Their Relationship with Photoluminescence

• Published in: Crystallography reports 2021-07, Vol.66 (4), p.636-643
• Main Authors: Fedina, L. I., Gutakovskii, A. K., Vdovin, V. I., Shamirzaev, T. S.
• Format: Article
• Language: English
• Subjects: Chemical bonds; Coalescing; Crystallography and Scattering Methods; Photoluminescence; Physical Properties of Crystals; Physics; Physics and Astronomy; Plastic deformation
• ISSN: 1063-7745; 1562-689X
• DOI: 10.1134/S1063774521040064

As a result of in situ irradiation in a high-resolution electron microscope, structure modelling, and calculation of images, it is shown that the incorporation of self-interstitial atoms into the extension region of the core of any dislocation is accompanied by their ordering in the form of cluster-like {111}, {001}, and {113} defects, which provide core relaxation. This fact made it possible to visualize for the first time the core structure of undissociated 60° dislocations of two types, glide ( ) and sessile ( ), which coexist at plastic deformation of Si. It is shown that incorporation of self-interstitial atoms into the dislocation core correlates with an increase of only the D 2 line in the photoluminescence spectrum, while perfect sessile a /2〈110〉 dislocations with a core, consisting of paired 5/7-link atomic rings without dangling bonds, are responsible for the rise of the D 1 line. This universal core occurs at coalescence of two dislocations during their slip in intersecting planes {111}, → transition, and transformation of a Frank dislocation into a perfect one.