Analysis of the three-dimensional ordering of epitaxial Ge quantum dots using focused ion beam tomography

Buried layers in quantum dot (QD) superlattices influence the position of QDs in the subsequently grown layers through strain field interactions. Since the strain interactions are complex, a three-dimensional reconstruction of the superlattice can enhance the fundamental understanding of self-organization mechanisms. We have studied the three-dimensional relationship of QDs using focused ion beam tomography. Analysis of the reconstruction is consistent with earlier models for self-organization. QDs on successive layers form above buried QDs. In certain cases, successive QDs in a column decrease in size, resulting in the elimination of the column while QDs in other columns grow in size. (c) 2006 American Institute of Physics.