Electrodeposition of cobalt nanowires on H-terminated conductive Si(111) surfaces using coblock polymer templating

Abstract

The authors have investigated the formation of block copolymer nanocavities on H-terminated conducting Si(111) surfaces as templates for the electrochemical growth of perpendicular metallic nanowire arrays. Poly(styrene)-block-poly(methyl methacrylate) block copolymers (PS-b-PMMA) of appropriate block length and PS to PMMA ratio were used to create a self-assembled array of perpendicular nanocavities in which the PS majority phase is continuous and surrounds cylinders of the minority PMMA phase. Here, we report that H-terminated conducting Si(111) surfaces are also capable of inducing a perpendicular orientation in block copolymers, which—in all likelihood—is a direct result of the H-termination (i.e., removal of the oxide layer). Atomic force microscopy reveals that an acetic acid wash of the annealed block copolymer causes the minority PMMA component to be rearranged, giving rise to cavities that are perpendicular to the conducting Si substrate. Subsequently, scanning electron microscopy reveals that electrodeposition into the nanocavities can be achieved, producing an array of metallic nanopillars, 20 nm in diameter.

Ordered arrays of ferromagnetic, compositionally graded Cu1−xNix alloy nanopillars prepared by template-assisted electrodeposition

“…The fabrication of large aspect ratio metallic nanowires in the cylindrical pores of membranes such as anodized alumina, polycarbonate and polymethyl methacrylate (PMMA) is well documented in the literature. [6][7][8][9] The diameter of the nanowires obtained ranges from hundreds down to tens of nanometres depending on the pore size of the template. The application of these 1D nanostructures in sensors, eld-emission and magnetic devices oen requires the nanostructures to be supported by a substrate (Si, glass, etc.)…”

Electro-oxidation of Ascorbic Acid by Cobalt Core–Shell Nanoparticles on a H-Terminated Si(100) and by Nanostructured Cobalt-Coated Si Nanowire Electrodes

“…To date, however, not much work has been reported on metallic Co nanostructure growth on Si substrates by electrodeposition. Recently, Curry et al electrodeposited perpendicular metallic Co nanowires (with an average diameter of 20 nm) on a H-terminated Si(111) substrate using the coblock polymer templating method . Moina et al reported the preparation of nano-sized Co nuclei on p-Si(111) by electrodeposition at −0.7 V (with respect to a saturated calomel electrode), for which “flat spheroids”, with maximum heights of ∼65 nm, were uniformly distributed on the Si surface .…”