field emission

Field emission is the process where electrons are pulled out of a material, often a metal, by applying a very strong electric field. Instead of needing heat or other energy sources, the electric field lowers the energy barrier that keeps electrons trapped inside. When the field is intense enough, electrons can tunnel through this barrier and escape into space. This phenomenon is used in devices like electron microscopes and vacuum electronic components. Essentially, a high electric field acts like a magnet—liberating electrons from the surface without heating the material.