Modeling the optical properties of Si-capped germanium quantum dots

We study theoretically the optical properties of Ge Si-capped quantum dots (QDs) with the aim to establish a relation between structure and properties. Specifically we study on how the imaginary part of the dielectric function and absorption coefficient depend on the shape and size of QDs. We have produced model structures with ultra small and very high density of quantum dots. For these models we studied the case of pyramid like or dome like QDs. What we observed is that the pyramid shape influences more the optical properties studied. Also the height-to-base aspect ratio contributes to the properties of the structure. Thus the optical properties can be used to monitor in situ the formation of the QDs.