fältemissions

Fältemission is a phenomenon where electrons are emitted from a solid surface due to a strong external electric field. This emission occurs when the electric field is sufficiently intense to distort the potential energy barrier at the surface of the material. Instead of requiring enough thermal energy to overcome the barrier, as in thermionic emission, fältemission relies on quantum mechanical tunneling. Electrons, behaving as waves, can penetrate the potential barrier even if their energy is classically insufficient.

The rate of fältemission is highly dependent on the applied electric field strength, the work function of the material, and the geometry of the emitting surface. Materials with low work functions, meaning they require less energy to remove an electron, are more prone to fältemission. Sharp tips or edges on a surface concentrate the electric field, leading to significantly higher emission current compared to flat surfaces. This effect is exploited in various technologies.

Applications of fältemission include field emission displays (FEDs), where arrays of tiny field emitters generate light. It is also crucial in electron microscopy, enabling the generation of high-brightness electron beams for imaging. Furthermore, fältemission is utilized in vacuum microelectronic devices and certain types of particle accelerators. The study of fältemission is fundamental to understanding electron behavior at material interfaces under extreme electrical conditions.