Control of ruthenium oxide nanorod length in reactive sputtering

Abstract

Ruthenium oxide nanorods have been grown on Si wafer substrates under a variety of pre-existing surface conditions by reactive radio frequency sputtering in an electron cyclotron resonant plasma process. Nanorod formation by this method is fast relative to that observed in other processes reported in the literature, with nucleation being the rate determining step. Growth in the axial direction is limited by the availability of ruthenium precursors which competes with their consumption in the lateral growth of the nanorods. The availability of Ru precursors at the top of the nanorods can be controlled by surface diffusion and therefore substrate temperature. The ultimate length of the nanorods is determined by the mole fraction of oxygen used in the reactor ambient through the production of mobile Ru hyperoxide precursors. The results of this investigation show the way to develop a process for producing a high density field of nanorods with a specified length.

Effect of Wetting on the Ability of Nanomaterials to Act as Effective Catalysts

“…The nanorods were deposited by a reactive sputtering process which is governed by a self-assembly mechanism that was discussed more fully in a previous publication [14]. The nanorods were found to be rectangular in shape and capped by a pyramid shaped termination, see Figure 1 [14].…”

“…by growing the NR samples for different lengths of time [14]. A collection of SEM images of different RuO 2 NR samples is shown in Figure 3.…”

“…A more complete description of these electrolysis experiments can be found in previously published work by Cross et al [3] [17]. The nanomaterial coated electrode surface is similar to the RuO 2 nanorods coated material whose SEM image was shown in Figure 1(a) [14]. The RuO 2 material is an electrical conductor and can be treated electrically as part of the electrode [15].…”

Structure and electro-catalytic properties of electrode materials consisting of Pt nanorod decorated/RuO2 nanorod coated substrates

“…Details of the process to produce the nanorods has been reported earlier [24]. The only change in the process required to obtain the Ptcontaining NR coating was to co-sputter from a second gun using a pure Pt target, in the later portion of the process used to obtain RuO 2 NRs.…”

“…The growth and characterization of RuO 2 nanorod materials has been reported earlier [24]. Previously the electro-catalytic properties of these RuO 2 nanorod materials was investigated and their ability to act as the electro-catalyst in the oxidation reaction occurring at the cathode in the electrolysis of an aqueous solution of KOH [13].…”