An important objective in surface science and modern technology is the development of simple recipes for fabricating nanostructures such as quantum dots, wires, and thin films. What makes the project challenging is that Nature places strict constraints on how atoms and surfaces interact. In general, you want the things you build on surfaces to stick. But you also want to move those same things into place. The first requires strong binding; the second, weak binding.
In 1998, John Weaver (University of Illinois, Urbana-Champaign) and collaborators resolved those conflicting requirements by developing a process that effectively replaces one surface with another. The process, buffer-layer assisted growth (BLAG), allows one to form assemblies of atoms on a weakly interacting buffer layer that can be evaporated afterward. 1 Using a buffer layer like solid xenon as a temporary proxy for the surface effectively changes the thermodynamics of the adatom-substrate system. Because atoms are...
