Electric-field-driven accumulation and alignment of CdSe and CdTe nanorods in nanoscale devices

Local electric fields generated by nanopatterned electrodes were used to control the position and orientation of well-isolated as well as closely packed colloidal semiconducting CdTe and CdSe nanorods (NRs) drop-cast from solution. Postdeposition imaging using transmission-electron microscopy and atomic-force microscopy revealed strong NR alignment to the direction of the applied field and dense accumulation around and onto voltage-biased electrodes when deposited from dilute and concentrated solutions, respectively. The degree of alignment under the applied electric field is characterized by a nematic order parameter S approximate to 0.8 in contrast to the zero-field case when S approximate to 0.1.