The Application of Dielectrophoresis to Nanowire Sorting and Assembly for Sensors

This manuscript describes a stochastic process in which a collection of nanowires is assembled on an array of electrodes for the purpose of making miniature gas sensors. The wires are not individually placed on the electrodes, but are assembled using fields, including fluid, gravity, and dielectrophoretic forces. Assembly through fields is scalable to high-throughput manufacturing processes, although it is also an underactuated control problem. To design an economical manufacturing process, a predictive physical model must first be developed. This model can then be used to design processes and devices that are less sensitive to the inherent noise in the assembly process, or that even provide built-in feedback during assembly. Real time feedback control could also be implemented using impedance spectroscopy. This work reviews the past research in nanowire assembly and describes some preliminary work of our group in the assembly tin oxide nanowires for gas sensors