Growth origin of large-scale fiberform nanostructures in He–W co-deposition environment

Abstract

When tungsten (W) is deposited with helium (He) plasma (He–W co-deposition) on W surface, enhanced growth of fiberform nanostructure (fuzz) occurs, and sometimes it grows into large-scale fuzzy nanostructures (LFNs) thicker than 0.1 mm. In this study, different numbers of mesh opening (apertures) and W plates with nanotendril bundles (NTBs), which are tens of micrometers high nanofiber bundles, were used to investigate the condition for the origin of the LFN growth. It was found that the larger the mesh opening, the larger the area where LFNs are formed and the faster the formation tends to be. On NTB samples, it was found that NTBs grew significantly when exposed to He plasma with W deposition, especially when the size of the NTB reached $$\sim 0.1$$ ∼ 0.1 mm. The concentration of the He flux due to the distortion of the shape of the ion sheath is proposed as one of the reasons to explain the experimental results.

A study of the formation of fuzzy tungsten in a HiPIMS plasma system

“…One major difference between the LPD and magnetron-gown fuzzy layers is that in the latter there is an intrinsic auxiliary source of tungsten W from the magnetron cathode target (also fixed to be W) due to low but detectable rates of helium ion sputtering. It has been shown in a number of studies that fuzzy tungsten growth rates (and the ultimate layer thicknesses) can be increased significantly if the heated W sample is being deposited upon from an auxiliary source of tungsten [7,17,19,20].…”