[7p-A201-1~10] Frontier of the research in dislocations

[7p-A201-5] Observation of threading dislocations in ammono-thermal gallium nitride single crystal by using synchrotron X-ray topography

〇Yongzhao Yao¹, Yukari Ishikawa¹, Yoshihiro Sugawara¹, Yumiko Takahashi², Keiichi Hirano² (1.JFCC, 2.KEK)

Keywords:GaN, X-ray topography, ammono-thermal

In this work, we have performed XRT observation on ammono-thermal GaN single crystal with varying diffraction vectors g, and dislocation categorization was discussed based on the results.
Synchrotron monochromatic-beam XRT was recorded from the Ga-face at BL-3C of KEK Photon Factory. Asymmetric diffractions with six equivalent g-vectors of 11-26 were applied by rotating the sample every 60^o with respect to its surface normal, in addition to a symmetric diffraction with g=0008. TDs within the topmost 10 μm surface have a major contribution to the spot-like contrast in the XRT images.