Motion control, planning and manipulation of nanowires under electric-fields in fluid suspension

Automated manipulation of nanowires and nanotubes would enable the scalable manufacturing of nanodevices for a variety of applications, including nanoelectronics and biological applications. In this paper, we present an electric-field-based method for motion control, planning, and manipulation of nanowires in liquid suspension with a simple, generic set of electrodes. We first present a dynamic model and a vision-based motion control of the nanowire motion in dilute suspension with a set of N × N controllable electrodes. Since the motion planning of a nanowire from one position to the target location is NP-hard, two heuristic algorithms are presented to generate near-optimal motion trajectories. We compare the heuristic motion planning algorithms with other existing algorithms such as the rapidly exploring random tree (RRT) and A∗ algorithms. The comparisons show that the proposed heuristic algorithms obtain near-optimal minimum time trajectories. Finally, we demonstrate a single, integrated process to position, orient, and deposit multiple nanowires onto the substrate. Extensive experimental and numerical results are presented to confirm the motion control and planning algorithms. Note to Practitioners - To fully realize the enormous potential of functional nanodevices, automated, scalable methods are needed to manipulate and assemble nanowires and nanotubes with controlled orientations at specific spatial locations. This paper presents one such technique for the automated motion planning, control and manipulation of individual nanowires suspended in a fluid. The design uses a set of electrode arrays to drive and orientate the nanowire from one location to the target location under electrophoretic and electro-osmotic forces. The motion modeling and control of an individual nanowire in fluid suspension are first presented to guide the nanowire to follow a given trajectory. Then, using the symmetry of the electric-field distribution, we present two heuristic nanowire motion planning algorithms to reduce the computational complexity. The algorithms are demonstrated and validated through experiments. We finally present several experiments demonstrating the steering and positioning of individual and multiple (in sequence) nanowires in a fluid suspension to form geometric patterns. The results will help provide a foundation for scalable, automated methods for manipulating nanowires to build nanodevices.