Metallic Conductive Nanowires Elaborated by PVD Metal Deposition on Suspended DNA Bundles

Abstract

Metallic conductive nanowires (NWs) with DNA bundle core are achieved, thanks to an original process relying on double-stranded DNA alignment and physical vapor deposition (PVD) metallization steps involving a silicon substrate. First, bundles of DNA are suspended with a repeatable process between 2 µm high parallel electrodes with separating gaps ranging from 800 nm to 2 µm. The process consists in the drop deposition of a DNA lambda-phage solution on the electrodes followed by a naturally evaporation step. The deposition process is controlled by the DNA concentration within the buffer solution, the drop volume, and the electrode hydrophobicity. The suspended bundles are finally metallized with various thicknesses of titanium and gold by a PVD e-beam evaporation process. The achieved NWs have a width ranging from a few nanometers up to 100 nm. The electrical behavior of the achieved 60 and 80 nm width metallic NWs is shown to be Ohmic and their intrinsic resistance is estimated according to different geometrical models of the NW section area. For the 80 nm width NWs, a resistance of about few ohms is established, opening exploration fields for applications in microelectronics.

Review of the Electrical Characterization of Metallic Nanowires on DNA Templates

“…For example, an electron beam evaporation process has been used for the direct metalization of DNA templates. Since this method relies on the homogeneous deposition of metal on large area, it is mostly used for suspended DNA nanostructures [ 19 ]. DNA nanostructures, which are solidly attached to a substrate, would be electrically shorted when evaporated with a metal, unless very anisotropic deposition is granted and the height of the DNA nanostructure exceeds the height of the evaporated metal.…”

“…Suspended nanowires, which were attached to lithographically defined gold electrodes by DNA combing during drying of the solvent, were characterized after deposition of gold layers. The resistance depends strongly on the resulting thickness of the wire after evaporation and was found to be, e.g., and for 80 and 60 width, respectively [ 19 ].…”

“…Electrical characterization of nanowires has been performed by either contacting them directly with electrodes [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] or using scanning probe microscopy [ 25 , 26 , 27 , 28 ]. In most measurements, contact resistances dominated over the contribution from the resistance along the wire, and careful studies of the conductance of the wires indicated that the resistivity is higher than purely metallic resistivity.…”

Bottom-Up Fabrication of DNA-Templated Electronic Nanomaterials and Their Characterization

“…This DNA can form templates for wires or transistors, which are used in nanoelectronic devices and circuits. Brun et al [ 35 ] formed metal NWs using λ-DNA bundles. The DNA solution was dropped on electrodes and allowed to evaporate, leaving a template; during deposition the metal self-aligned with the DNA template.…”

Phase‐Regulated Sensing Mechanism of MoS2 Based Nanohybrids toward Point‐of‐Care Prostate Cancer Diagnosis

“…[ 21,22 ] Metal materials, especially at the nanoscale, are recognized for their many unique applications, including energy storage and conversion, catalysis, sensing, and biomedicine. [ 23–25 ]…”