Stacking Fault Manifolds and Structural Configurations of Partial Dislocations in InGaN Epilayers

The configurations of basal stacking fault (BSF) manifolds often observed in III-nitride alloy epilayers, particularly InGaN, are considered herein. Using high-resolution transmission electron microscopy (HRTEM), it is shown that the folds and steps of intrinsic BSFs can acquire a Shockley-like partial dislocation character depending on the relative senses of the BSF stackings. This can lead to the introduction of extra geometrically necessary threading dislocations in the epilayer on account of variant coexistence. Moreover, it is demonstrated that the overlap of two I-1 BSFs can transform into a single I-2 BSF, which is terminated by a glissile Shockley dislocation. Shockley and Shockley-like partial dislocations can acquire line directions comprising either <1 over bar 1 over bar 20> a-line or 1 over bar 00> m-line segments. Using atomistic calculations, the core structures of the m-line partials are provided and their visibility is examined by HRTEM as well as the possibility of their discrimination from the a-line ones.