Scalable Self-Limiting Dielectrophoretic Trapping for Site-Selective Assembly of Nanoparticles.

Abstract

The absence of a versatile, scalable, and defect-free bottom-up assembly of nanoparticles with high precision has been a longstanding roadblock facing the large-scale integration of diverse nanoparticle-based devices. To circumvent this roadblock, we present a self-limiting dielectrophoretic approach to precisely align nanoparticles onto an array of electrodes over a large area, assisted by lithographically defined capacitors in series with the electrodes. We have experimentally verified that the on-chip capacitor can reduce the probability of trapping multiple particles at a given site, as the electric field is greatly weakened after the first nanoparticle bridges the electrodes. A 70% yield of single-nanowire assembly has been achieved, and key factors limiting the current yield are discussed. The yield is expected to further increase by improving the nanoparticle-electrode contact and reducing the capillary force during the drying process. We also demonstrate the versatility of this approach for scalable and site-selective alignment of various nanoparticles.