Here we report on the DNA-templated self-assembly of conducting gold nanowires between gold electrodes lithographically patterned on a silicon oxide substrate. An aqueous dispersion of 4-(dimethylamino)pyridine-stabilized gold nanoparticles was prepared. These nanoparticles recognize and bind selectively double-stranded calf thymus DNA aligned between the gold electrodes to form a linear nanoparticle array. Continuous polycrystalline gold nanowires are obtained by electroless deposition that enlarges and enjoins the individual gold nanoparticles. The above nanowires were structurally characterized using a range of electron and scanning probe microscopies and electrically characterized at room temperature using a standard probe setup. The results of these characterizations show these wires to be 20 nm high and 40 nm wide, to be continuous between interdigitated gold electrodes with an interelectrode spacing of 0.2 or 1.0 μm, and to possess a resistivity of 2 × 10-4 Ωm. These DNA-templated nanowires, the smallest reported to date, exhibit resistivities consistent with reported findings and current theory. The use of DNA as a template for the self-assembly of conducting gold nanowires represents a potentially important approach to the fabrication of nanoscale interconnects.

No abstract

Bernshtein–von Mises theorems, Dirichlet process, Hilbert and Stieltjes transforms, mixtures, nonparametric Bayes, random probability measure, stochastic equation, 62G99, 62F15,

The demand for integrated circuits that will allow information to be processed at even faster speeds remains undiminished. This is despite the fact that, as a result of miniaturization, the density of the wires and switches that comprise such circuits has doubled every eighteen months, giving rise to Moore's Law. [1] While it is expected that Moore's Law will hold true until 2016, it is not expected that it will hold true thereafter for two reasons. [2] The first reason is that to build smaller wires and switches requires major advances in the established fabrication and materials technologies. Specifically, it requires the development at great cost of new light sources and process tools; new mask and resist materials; and new high-and low-dielectricconstant materials. The second reason is that as wires and switches become smaller, the materials of which they are composed no longer exhibit bulk properties, but exhibit properties dominated by confinement and surface effects.The responses of the related scientific and engineering communities have been two-fold. The first response has been to develop alternative fabrication technologies. The second response has been to propose new integrated circuit architectures that can accommodate or even exploit the novel properties exhibited by these smaller wires and switches.When contemplating alternative fabrication technologies, one is immediately attracted to the self-assembly in solution and self-organization at a conventionally patterned silicon wafer substrate of nanoscale wires and switches. [3] When contemplating alternative materials technologies, one is immediately attracted to the use of biological molecules as templates and modified nanoparticles as building blocks. [4,5] It is noted that there have been a number of recent reports that have demonstrated the potential of these and related approaches. [6±10] It is in this context that we report the deoxyribonucleic acid (DNA) templated assembly of a protein-functionalized 10 nm gap electrode from suitably modified gold nanoparticles on a silicon wafer substrate. We also report that the above proteinfunctionalized electrode is recognized and bound selectively by a suitably modified gold nanoparticle and is localized in the 10 nm gap.Our five-step strategy is illustrated in Figure 1. The first step is to assemble a thiol-DNA-biotin template in solution and to deposit it on a silicon wafer substrate. It is expected that in the future these thiol groups will locate the template in the gap between the conventionally patterned gold electrodes. The second step is to expose the substrate to a dispersion of suitably modified gold nanoparticles. These nanoparticles selectively bind the DNA backbone of the template, leading to its partial metallization. The third step is to expose the substrate to a dispersion of the protein streptavidin. This protein recognizes and selectively binds the biotin located at the midpoint of the template. Furthermore, this protein displaces any partially bound gold nanoparticles in the vicinity ...