Predictive Assembly of Nanowire Arrays using Floating Electrode Dielectrophoresis

Functional device integration using dielectrophoretic nanoassembly presents important opportunities in diverse applications ranging from nanoelectronics to sensors and energy nanosystems. In recent studies, floating electrode dielectrophoresis has demonstrated alignment precision, directional deposition and relatively better control during the nanoassembly process as compared to conventional dielectrophoresis. This thesis focuses on a 3-D electrokinetic model for predictive assembly of nanowires using floating electrode dielectrophoresis. A study of the nanowire (NW) trajectories and their localization sites on electrodes, which result from floating electrode dielectrophoresis, was carried out using the COMSOL and MATLAB platforms. Three-dimensional finite element models were produced using the COMSOL software, to calculate the electric field distribution generated by an array of electrode pairs on silicon chips. Results acquired after the analysis were imported to a MATLAB environment, in order to predict the dielectrophoretic forces and trajectories followed by NWs towards eventual deposition on electrodes. Moreover, the effect of DEP parameters such as deposition time, biasing voltage and NW size on the deposition process (in terms of NW trajectory, assembly position and orientation) was investigated. The accuracy of the finite element models was validated through direct quantitative comparison with the experimental results. The presented modeling approach and its analysis has the potential to enable predictive and scalable assembly of nanomaterials into functional nanodevices.