We review recent results obtained in our lab that show how patterns of colloidal nanoparticles can be reliably constructed by pushing them on a surface with the tip of an Atomic Force Microscope (AFM).
Nanoparticle patterns have many potential applications, such as high-density digital storage, single-electron transistors, and templates for growth of nanoelectromechanical systems (NEMS) and components.Our experiments are conducted in air at room temperature, using commercial AFMs and tips, and our own Probe Control Software (PCS), which runs on top of the vendor-supplied Application Programming Interface (API). We have been able to accurately and reliably position commercially-available colloidal gold particles with diameters between 5 and 30 nm on mica and silicon substrates.
Mica was coated with poly-L-lysine, and silicon with a self-assembled silane monolayer.An extensive set of experiments and simulations provide insights into the phenomena which underlie the manipulation operations, and into the parameters and strategies needed for success.
Operations can be monitored in real time, and the acquired signals can be used to help automate the procedures.We focus on experiments in constructing assemblies of nanoparticles, linking them using di-thiols, and translating and rotating the linked assemblies. We also show that it is possible to create simple three-dimensional nanostructures by pushing particles over steps and previously-constructed structures.