Figure 1.

(Color online). a Scanning electron micrograph of the stripe in a region of the sample without pit patterning before (upper inset) and after (main panel) a 7.5-min annealing at 625°C. The lighter part at the center of the image is the Ge stripe. The shading at the sides of the stripe results from the compositional contrast of the secondary electron emission between Ge, diffused on the surface, and Si in the substrate. b Thickness (filled black squares) and composition (open blue circles) of the diffused over-layer upon the distance, x, from the stripe edge, as obtained by monitoring the Ge LMM and Si LMM Auger lines and fitting their intensities with a discrete layer model (see text)