Synchrotron X‐ray diffraction studies of large sapphire crystal grown by Kyropoulos‐like method

Abstract

In this paper, monochromatic double‐crystal X‐ray diffraction and white‐beam X‐ray topography techniques using synchrotron radiation source were utilized to investigate the growth process of large sapphire crystal by an improved Kyropoulos‐like method. Compared with the calculated theoretical value of 8.6 s, FWHM experimental values of sapphire are in the range of 11 ∼ 26 s, showing its good crystalline perfection in general, especially for the crystal in the central region of the boule. The analysis of white beam transmission X‐ray topographs revealed the presence of dislocation tangles and helical dislocations in different crystal regions. The defect configurations in sapphire crystals were caused by the dislocation reaction and void formation.