Chemically Assisted Directed Assembly of Carbon Nanotubes for the Fabrication of Large-Scale Device Arrays

Abstract: We report the directed assembly of SWCNTs at lithographically defined positions on gate oxide surfaces, allowing for the high-yield (~90%) and parallel fabrication of SWCNT device arrays. SWCNTs are first chemically functionalized through diazonium chemistry with a hydroxamic acid end group that both renders the SWCNTs water soluble and discriminately binds the SWCNTs to basic metal oxide surfaces (i.e. HfO2). The functionalized SWCNTs are then assembled from an aqueous solution into narrow trenches etched into SiO2 films with hafnium oxide (HfO2) at the bottom. The side walls of the patterned trenches induce alignment of the SWCNTs along the length of the trenches. Heating the structures to 600^oC, removes the organic moieties, leaving pristine SWCNTs as evidenced by Raman spectroscopy and electrical measurements. Palladium source and drain electrodes deposited perpendicular to the trench length, readily contact the ends of the aligned SWCNTs. The resultant devices exhibit the superior electrical performance expected for SWCNT devices, with no performance deterioration as a result of the placement process. This technique allows for the directed assembly and alignment of SWCNTs over a large area and results in a high yield of working devices, presenting a promising path toward large-scale SWCNT device integration.