Grain dynamics make perfectly flat copper films impossible

Scientists in the Republic of Ireland, the US and the UK have discovered that nanocrystalline copper films are not as flat as they may seem. Using scanning tunnelling microscopy (STM) to map the surfaces of copper films with atomic detail, the researchers revealed that the grains in copper rotate and misalign in an effort to reduce grain boundary energy, resulting in a surface topography marred by valleys and ridges……..