Citrate-stabilized palladium nanoparticles as catalysts for sub-20 nm epitaxial silicon nanowires

Abstract

Citrate-stabilized palladium nanoparticles with a mean diameter of 13 nm were synthesized in aqueous solution. These particles were utilized as catalysts to grow epitaxial silicon nanowires by chemical vapor deposition at temperatures below 500 °C. The resulting nanowires have a mean diameter of 15 nm. It is found that during the growth process the palladium particles transform into dipalladium silicide.

Palladium(0) Nanoparticle Formation, Stabilization, and Mechanistic Studies: Pd(acac)2 as a Preferred Precursor, [Bu4N]2HPO4 Stabilizer, plus the Stoichiometry, Kinetics, and Minimal, Four-Step Mechanism of the Palladium Nanoparticle Formation and Subsequent Agglomeration Reactions

“…132,133 Of interest here is that citrate 3− , with its tridentate facial O 3ligating ability (e.g., as tested with Ir(0) nanoparticles 115,119 ), has also been employed as a stabilizer for 13 ± 4 nm Pd(0) n nanoparticles, Table 1, and the resulting nanoparticles have been used as a catalyst for epitaxial growth of silicon nanowires. 134 Of even greater interest to the present work emphasizing HPO 4 2− as a stabilizer is that the vanadium congener, HVO 4 2− , with its facial O 3 -array and O−O distance of 2.76 Å (in comparison to the estimated ∼2.64 Å Pd−Pd distance for Pd(0) n nanoparticles 132 ) has been reported to yield stable Pd(0) n nanoparticles in aqueous solution that were then supported on carbon black. The HVO 4 2− anion was also reported as being removable by washing to yield carbon-supported Pd(0) n nanoparticles of average size 4.8 nm (and size distribution ranging from 3.2 to 6.0 nm).…”

Simple Synthesis of Palladium Nanoparticles, β-Phase Formation, and the Control of Chain and Dipole Orientations in Palladium-Doped Poly(vinylidene fluoride) Thin Films

“…In this work, we explore the possibility of fully nucleating the β phase in PVDF thin films by palladium nanoparticles (Pd-NP's) doping as well as the preparation of Pd-NP's by a facile route. It is worth noting that the most of the available techniques such as wet-chemical synthesis, intercalation, pulsed-laser ablation, electrochemistry, sputtering, physical vapor deposition, microwave plasma, thermal decomposition, and so forth either involve multiple steps or need highly sophisticated equipment. − In this respect, our methodology of Pd-NP preparation is not only simple but also cost-effective. It is well known that Pd has enormous capability for hydrogen storage (e.g., 1 volume unit of Pd holds 643.3 volume units of hydrogen) .…”

Seeded silicon nanowire growth catalyzed by commercially available bulk metals: broad selection of metal catalysts, superior field emission performance, and versatile nanowire/metal architectures

“…36 In a Type III metal-seeded growth, nanosized metal silicides serve as seeds for nucleation and growth of Si nanowires through solidphase bulk or surface diffusion. [37][38][39][40] Fig. 3 Our synthesis results show that bulk Ag, Al, Cu, Fe, Ni, Pb and Ti are effective catalysts for wire growth.…”