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Earlier images describe how strained layer epitaxy allowed us to merge crystals of GeSi and Si. Subsequent images descirbe how we fabricate these layers into various electronic devices. This atomic force microscope image represents an attempt to let nature do part of that fabrication work. Normally we try very hard to grow smooth continuous layers. Here we deliberately screwed things up by growing GeSi on Si at too high a temperature. Because of its different chemistry, the GeSi tends to ball up into tiny islands, the microscopic analog of water beading on a clean piece of glass. Normally these islands are of all different sizes. Here, however, other GeSi layers have been buried more deeply to produce strain fields that cause the final islands to grow in a much more regular and organized manner. These "self-assembled" islands are of a size and configuration that might someday be used directly as electronic devices such as the "quantum cellular automata.". We have not yet got the perfection that would require, but we're working on it.
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