Abstract
The two-dimensional (2D) to three-dimensional (3D) morphological transition in strained Ge layers grown on Si(001) is investigated using scanning tunneling microscopy. The initial step takes place via the formation of 2D islands which evolve into small ( Å) 3D islands with a height to base diameter ratio of , much smaller than the 0.1 aspect ratio of -faceted pyramids which had previously been assumed to be the initial 3D islands. The “prepyramid” Ge islands have rounded bases with steps oriented along and exist only over a narrow range of Ge coverages, 3.5–3.9 monolayers.
- Received 24 May 2000
DOI:https://doi.org/10.1103/PhysRevLett.85.3672
©2000 American Physical Society