V. Yam et al., Photoluminescence study of a bimodal size distribution of Ge/Si(001) quantum dots - art. no. 033313, PHYS REV B, 6303(3), 2001, pp. 3313
This work presents a study an the effect of a bimodal size distribution and
of the pyramid/dome transition to the optical properties of self-assembled
Ge/Si quantum dots. The wetting layers are shown to be inhomogeneous in th
ickness due to lateral diffusion of Ge from two-dimensional (2D) layers tow
ards islands of bimodal sizes, while the island-related photoluminescence r
emains unchanged. The results indicate that three-dimensional islands, at t
heir early stages of nucleation, are formed by consuming Ge from 2D layers
and that the island luminescence energies are more sensitive to Ge/Si inter
diffusion than the confinement effect inside the islands as currently belie
ved.