Rapid and mass growth of stress-induced nanowhiskers on the surfaces of evaporated polycrystalline Cu films

The rapid and mass growth of Cu nanowhiskers on polycrystalline films has been realized. The diameter and length of the nanowhiskers are governed by temperature, film thickness, grain size and time. Here we report a mechanism for the growth of the nanowhiskers. Cu atoms diffuse due to local stress gradients in the grains which originate in the material and geometrical singularities caused by anisotropy. Weak spots in the oxide layers on the films act as initiation sites for the nanowhiskers.