Electron hole
An electron hole (often simply called a hole) is the absence or lack of an electron where an electron would normally be in an atom. Because electrons are negative and their charges are balanced by the positive protons, electron holes are positive in charge. Electron holes are not particles, they are classified as quasiparticles. Electron holes are different to positrons, which are the antiparticle to the electron. When electrons change energy levels, they leave an electron hole in their place.
Electron Hole Media
When an electron leaves a helium atom, it leaves an electron hole*in its place. This causes the helium atom to become positively charged.
A children's puzzle which illustrates the mobility of holes in an atomic lattice. The tiles are analogous to electrons, while the missing tile (lower right corner) is analogous to a hole.
A semiconductor electronic band structure (right) includes the dispersion relation of each band, i.e. the energy of an electron E as a function of the electron's wavevector k.
