Tungsten oxide thin film bombarded with a low energy He ion beam: evidence for a reduced erosion and W enrichment

• Published in: Physica scripta Vol. T170; no. 1; pp. 14019 - 14023
• Main Authors: Martin, C, Hijazi, H, Addab, Y, Domenichini, B, Bannister, M E, Meyer, F W, Pardanaud, C, Giacometti, G, Cabié, M, Roubin, P
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.12.2017
• Subjects: Condensed Matter; electron microscopy; erosion; He ion bombardment; Materials Science; Physics; Plasma Physics; Raman spectroscopy; sputtering yield; tungsten oxide; x-ray photoelectron spectroscopy; He ion bombardment; sputtering yield; tungsten oxide; erosion; thin film; electron microscopy; Raman spectroscopy
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/1402-4896/aa89c1

Nanocrystalline tungsten oxide (WO3) thin films synthesized by thermal oxidation of tungsten substrates were exposed to low energy helium ions (energy: 80 eV; flux: 1.4-1.7 × 1020 m−2 s−1) at room temperature and at 673 K. The structure and morphology changes of the oxide were studied using Raman spectroscopy and electron microscopy. Due to the low ion energy, no erosion is observed at room temperature. In contrast, at 673 K, a color change is observed and a significant erosion is measured (∼70 nm for a fluence of ∼4 × 1021 m−2) due to a synergetic effect between ion bombardment and heating. We show that erosion processes and structural changes strongly depend on the ion fluence and in particular the higher the fluence, the lower the erosion yield, most likely due to oxygen depletion in the oxide near-surface layers.