Cuenat, AlexandreAziz, Michael2009-04-212002Cuenat, Alexandre and Michael J. Aziz. 2002. Spontaneous Pattern Formation from Focused and Unfocused Ion Beam Irradiation. Materials Research Society Symposium Proceedings 696, N2.8.0272-9172http://nrs.harvard.edu/urn-3:HUL.InstRepos:2797441We study the formation and self-organization of "ripples" and "dots" spontaneously appearing during uniform irradiation of Si, Ge, and GaSb with energetic ion beams. Features have been produced both with sub-keV unfocused Ar+ ions and with a 30 keV Ga+ Focused Ion Beam. We follow the evolution of features from small amplitude to "nanospikes" with increasing ion dose. It appears that the edge of the sputtered region influences the patterns formed, an effect that may make it possible to guide the self-organization by the imposition of lateral boundary conditions on the sputter instability.en-US10.1557/PROC-696-N2.8