Effects of Substrate Temperature on Helium Content andMicrostructure of Nanocrystalline Titanium Films

Abstract

Helium-charged nanocrystalline titanium films havebeen deposited by He–Ar magnetron co-sputtering. The effects of substratetemperature on the helium content and microstructure of the nanocrystalline titaniumfilms have been studied. The results indicate that helium atoms with a highconcentration are evenly incorporated in the deposited titanium films. When thesubstrate temperature increases from 60°C to 350°C while the otherdeposition parameters are fixed, the helium content decreases gradually from38.6 at.% to 9.2 at.%, which proves that nanocrystalline Ti films have a greathelium storage capacity. The 2θ angle of the Bragg peak of (002) crystal planesof the He-charged Ti film shifts to a lower angle and that of (100) crystal plane isunchanged as compared with that of the pure Ti film, which indicates that thelattice parameter c increases and a keeps at the primitive value. The grainrefining and helium damage result in the diffraction peak broadening.