Surface Phenomena During Plasma-Assisted Atomic Layer Etching of SiO.

Surface phenomena during atomic layer etching (ALE) of SiO were studied during sequential half-cycles of plasma-assisted fluorocarbon (CF) film deposition and Ar plasma activation of the CF film using in situ surface infrared spectroscopy and ellipsometry. Infrared spectra of the surface after the CF deposition half-cycle from a CF/Ar plasma show that an atomically thin mixing layer is formed between the deposited CF layer and the underlying SiO film. Etching during the Ar plasma cycle is activated by Ar bombardment of the CF layer, which results in the simultaneous removal of surface CF and the underlying SiO film.

Hydrogen spillover in Pt-single-walled carbon nanotube composites: formation of stable C-H bonds.

Using in situ electrical conductivity and ex situ X-ray photoelectron spectroscopy (XPS) measurements, we have examined how the hydrogen uptake of single-walled carbon nanotubes (SWNTs) is influenced by the addition of Pt nanoparticles. The conductivity of platinum-sputtered single-walled carbon nanotubes (Pt-SWNTs) during molecular hydrogen exposure decreased more rapidly than that of the corresponding pure SWNTs, which supports a hydrogenation mechanism facilitated by "spillover" of dissociated hydrogen from the Pt nanoparticles. C 1s XPS spectra indicate that the Pt-SWNTs store hydrogen by means of chemisorption, that is, covalent C-H bond formation: molecular hydrogen charging at elevated pressure (8.