All solar cells require a light absorbing material contained within the cell structure to absorb photons and generate electrons via the photovoltaic effect.

The triggering spark also generates ultraviolet light and free electrons in the main gap.

Another mechanism to generate free electrons from a cold metallic surface is field electron emission.

Electron gun, used to generate electrons by way of thermionic or field emission from a source tip.

The background light also generates electrons, which have to be stored.

These collisions generate very high-energy electrons and their positively charged twins, positrons.

Another manifestation of the photoelectron effect is exposure to X-ray generated electrons from thick gold films used for making daughter masks.

A particle accelerator generating high energy protons, electrons or charged ions.

This process repeats nine times, each time generating more and more electrons.

For negative corona, instead, the dominant process generating secondary electrons is the photoelectric effect, from the surface of the electrode itself.