Evidence from atomistic simulations of fluctuation electron microscopy for preferred local orientations in amorphous silicon

The preferred local orientations in amorphous silicon were investigated for evidence from atomistic simulations of fluctuation electron microscopy (FEM). The order consisted of correlations in the orientation of nearby paracrystalline grains or anisotropy in the grain shape. When all the grains were oriented along the same axis, the second peak was larger than the first, provided that there was a sufficient volume fraction of the grain. The results show that the peak height ratio in FEM is sensitive to orientational order and the shape of the paracrystalline grains.