Abstract
We performed a nanostructure analysis of diamond-like carbon (DLC) nanowires used to compose nanosprings fabricated by focused-ion-beam chemical vapor deposition (FIB-CVD). The DLC nanowires of the as-grown nanosprings had elastic double structures, in which a 50-nm-diameter core containing 3-at. % gallium (Ga) in addition to carbon (C) was enclosed in an outer 25-nm-wide DLC shell. The Young's modulus of the core was 322 GPa, approximately 12 times that (26 GPa) of the DLC shell. Energy dispersion X-ray spectroscopy (EDX) revealed that the C densities of the core and the shell were similar, indicating that the density of the core was higher than that of the shell owing to the incorporation of Ga into the core. However, the core density was approximately halved by 800 °C annealing. This is attributed to the vaporization of Ga and the movement of C from the core to the shell.