Thermo mechanical properties and plastic deformation of gold nanolines and gold thin films

The material behavior of nano-shaped and -scaled materials is a key issue for their system integration in modern micro electro-mechanical systems (MEMS). In this article, the thermo mechanical properties of (i) homogeneous gold thin films with a thickness of 20 nm on polyimide substrate and (ii) gold nanoline ensembles with 40 nm width, 20 nm height and 1 mm length on polyimide substrate were measured using the synchrotron based sin2(φ)-tensile testing technique. Both, passivated and unpassivated samples were tested in a temperature range of 173–393 K. As main findings: (i) homogeneous thin films are remarkably stronger than the nanolines, (ii) the yield strength shows a strong temperature dependence, and (iii) the yield strength of passivated samples is significantly increased compared to their unpassivated counterparts. The activation energy also shows a pronounced temperature dependency and indicates plastic deformation controlled by (i) dislocation motion for temperatures below 223 K, (ii) diffusion along (1 1 1) surfaces in the temperature range of 223–343 K and (iii) diffusion along the remaining surfaces (others than (1 1 1)) in the temperature range of 334–393 K.

► Thermo-mechanical properties of Au thin films and Au nanowires. ► Yield strength is strongly temperature dependent. ► Au thin films are stronger compared to Au nanolines. ► Passivation of samples raises yield strength. ► Stress–strain behavior can be fitted by general diffusion-base creep model.