Artificially positioned multiply-stacked Ge dot array

For our previously proposed method of forming an artificially sized and positioned Ge dot array by the use of inverse-pyramid shape pits as an anchor for Ge dot positioning, we cleared the Ge dot positioning behavior, which depends on the anchor pit pitch and the Ge growth temperature. The results suggest that, with the pits, Ge dot positioning behavior still relates to the dot self-organizing mechanism itself in addition to the Ge migration behavior. On the basis of the results, their artificial positioning can be controlled by setting the pit pitch within the range between the self-organized Ge dot space and the Ge migration length. Using this method, an artificially aligned multiply-stacked Ge dot array was also demonstrated.