Field electron emission

Field electron emission is the process where electrons are released from a metal or other material when a strong electric field is applied. The electric field lowers the energy barrier at the surface, allowing electrons to "tunnel" through it even without thermal energy. This phenomenon is used in devices like electron microscopes and high-vacuum electronic components for its ability to generate precise, high-speed electron beams. It relies on quantum tunneling, where electrons pass through an energy barrier that they'd normally be unable to cross, controlled by intense electric fields at the material's surface.