Scientists at the University of Alberta in Canada discovered a process to create the sharpest tip in the world. In fact, it’s kind of like sharpening a pencil. You begin with a rod. As you sharpen it, the wood and lead surrounding the center fall away, leaving a sharp point.
The researchers discovered a way to do something similar with a very fine needle. Like everything else, the tip of a needle is made of atoms. Normally, though, the atoms at the very tip are constantly smudging away. The University of Alberta scientists figured out a way to make the tip consist of a single atom.
They coated the surrounding atoms with nitrogen, which made them fall away, leaving only the single-atom tip.
For some reason nitrogen affects only the atoms around the edges, so you end up with an incredibly fine, sharp tip which is useful for emitting electron beams for electron microscopes.