Ion Beam Induced Nanostructures

It is reported about two techniques to produce nanostructures on surfaces by low-energy ion bombardment. The ability to predict and control nanostructural details on surfaces is seen as crucial. The aim of these two ion beam assisted techniques is to generate well-defined nanostructures on surfaces.

(1) Nanostructuring by ion-beam erosion. Due to different roughening mechanisms a multitude of topographies can result from surface erosion by low-energy ion beams. Under certain conditions, sputtering can roughen the surface resulting in a pronounced topography evolution in some cases producing well-ordered patterns. The underlying mechanism for the evolution of regular nanometer structures is a self-organization process caused by the interplay of roughening by curvature dependent sputtering and surface smoothing by different surface relaxation mechanisms.

(2) Nanostructuring by ion beam assisted glancing angle deposition. A new class of engineered surface nanostructures in which their shapes (multible zigzags, helices, etc.) can be changed instantaneously during their growth evolution is presented. In this technique, the flux of the sputtered atoms is incident upon a substrate from highly oblique angles. This condition is sufficient to create a state of significantly enhanced surface shadowing. By rotation the around a second axis passing perpendicular through the substrate, the resulting microstructure will be helical.