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Unformatted text preview: Requicha et al. Nanomanipulation with AFMs 1 Algorithms and Software for Nanomanipulation with Atomic Force Microscopes A. A. G. Requicha, D. J. Arbuckle, B. Mokaberi and J. Yun Laboratory for Molecular Robotics University of Southern California Los Angeles, CA 90089-0781, USA [email protected] Abstract Interactive manipulation of nanoparticles by mechanically pushing them with the tip of an AFM (Atomic Force Microscope) is now done routinely at many laboratories around the world. However, a human in the loop introduces significant inaccuracies and results in a very slow process, mostly because of the need for locating the particles before and after manipulation operations, in the presence of large spatial uncertainties which are often comparable to the size of the particles. This paper describes the nanomanipulation systems developed at USC’s Laboratory for Molecular Robotics over the last decade, culminating in a fully automatic system that is capable of accurately positioning small nanoparticles, with diameters ~ 10 nm. This system uses software compensators for the nonlinearities inherent in the piezoelectric actuators used in most AFMs. The planner and execution systems are described, as well as the software architecture of the systems. Experimental results are presented that validate the approach and show that nanoparticle patterns that would take hours to build interactively can now be built in minutes. Automatic operation makes possible the construction by manipulation of nanostructures much more complex than those built in the past. 1. Introduction Scanning Probe Microscopes (SPMs) have provided a unique window into the nanoworld since their invention in the mid 1980s. They have remarkable imaging and measurement capabilities, which range from atomic-resolution topographical (i.e., height) images of surfaces, to density-of-states images, to measurement of electrostatic, magnetic and bond- breaking forces, to name a few. SPMs not only can probe materials but can also modify them at the nanoscale, and have been widely used by the nanorobotics community for manipulating nanoparticles, nanowires, nanotubes and other objects that may serve as building blocks for the bottom-up assembly of nanostructures. Atomic manipulation was demonstrated soon after the invention of the SPM. It can provide new insights into nanoscale phenomena, but it does not seem very useful for building devices and systems at the nanoscale. Typically, atomic manipulation is done in UHV (ultra high vacuum) at temperatures near 0 K, it is too slow for engineering Requicha et al. Nanomanipulation with AFMs 2 applications since it relies on placing a single atom at a time to build a nanostructure, and has difficulties ensuring that intermediate constructions are stable....
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- Spring '08
- Algorithms, Particle, Orders of magnitude, AFMs, A. G. Requicha, A. A. G.