Ultrasound-assisted oxidation of tungsten in oxygen plasma: the early stages of the oxide film growth

Abstract

The effect of ultrasonic vibrations applied in situ on the formation of W-WO interface during the exposure of a pure tungsten foil to a low-temperature oxygen plasma is investigated by photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The tungsten surface was exposed to oxygen plasma at different time intervals and the evolution of the interface formation was studied by angle-resolved XPS. We show that oxidation without ultrasonic vibrations leads to the formation of a thin oxide film whose growth kinetics is governed by an island growth mechanism. On the other hand, oxide growth in the presence of ultrasonic treatment (UST) appears to follow a layer-by-layer growth mode with a distinctly sharper W-WO interface. TOF-SIMS analysis in this case revealed a reduced amount of water bonded in the film, which suggests an increase in the film's packing density.

Nano-Size Phase Formation at Acoustically Stimulated Ion Beam Synthesis

“…A number of effects taking place, when this method was applied to the ion-beam synthesis of nanoclusters [7][8][9], buried dielectric layers [10,11], oxidation of metallic films [12][13][14], amorphization of silicon surface layers [15][16][17][18], introduction of electrically active impurities [19][20][21], and relaxation of mechanical stresses in nano-sized thin-film systems [22], were studied. It should be noted that the effects concerned can be observed only if the process of ion implantation was carried out simultaneously with the US treatment of a target.…”

Ambient Pressure Synthesis of Nanostructured Tungsten Oxide Crystalline Films

“…Several studies have been conducted by using various techniques, including the oxygen plasma processing [5], plasma sputtering [6], chemical solution [7,8], sol-gel techniques [9], electron beam evaporation deposition [10], electrochemical etching [11], and the chemical vapor deposition techniques [12]. Most work concerned the synthesis of nanoparticles for catalytic applications based on chemical solution methods [4,[7][8][9].…”

Study of the structural evolutions of crystalline tungsten oxide films prepared using hot-filament CVD

“…Over the last decade, tungsten oxide (WO 3 ) films have attracted much interest due to their enormous potential for catalytic [2,3], gas sensors [4,5], high-resolution flat display [5] and electrochromic material [6] applications. Several studies have been conducted using various techniques, including the oxygen plasma processing [7], plasma sputtering [8], chemical solution [9,10], sol-gel techniques [6,11], electron beam evapouration deposition [12], electrochemical etching [13] and chemical vapour deposition techniques [14].…”