Unambiguous Determination of Local Orientations of Polycrystalline CuInSe2 Thin Films via Dictionary‐Based Indexing

The present work describes the approach of how to determine local orientations in individual CuInSe2 grains from electron‐backscatter diffraction (EBSD) data, in spite of the very small deviation (0.3%) of the ratio of lattice constants of the tetragonal crystal structure, c/a, from the value in the pseudocubic case, 2. A dictionary‐based indexing algorithm is applied on each EBSD pattern, determining unambiguously the corresponding CuInSe2 crystal orientation of the tetragonal structure. The approach provided in the present work can be used to improve the studies of microstructure–property relationships in various relevant photovoltaic material systems with similar pseudosymmetrical crystal structures, such as kesterite‐type or halide‐perovskite thin films.