Electron-hole recombination

Article By:

Frenzel, Louis Retired, Department of Engineering Technology, Austin Community College, Austin, Texas.

Berry, Carlotta Department of Electrical & Computer Engineering, Rose-Hulman Institute of Technology, Terre Haute, Indiana.

Last reviewed:April 2022

DOI:https://doi.org/10.1036/1097-8542.224150

Show previous versions

• Electron-hole recombination, published June 2020:Download PDF Get Adobe Acrobat Reader

The process in which an electron, which has been excited from the valence band to the conduction band of a semiconductor, falls back into an empty state in the valence band, which is known as a hole. When atoms come together to form a crystal, the discrete atomic energy levels broaden into a level continuum. The periodic potential of the crystal produces gaps in the continuum, separating it into a number of energy bands. In a pure semiconductor crystal, bonding electrons fill the valence band, and above the valence band in energy is an empty conduction band. The two bands are separated by the band gap, which has no levels, and the extent of this band gap is a characteristic of each semiconductor. The band gap is of order 1 eV for common semiconductor materials such as silicon (Si) or gallium arsenide (GaAs). See also: Band theory of solids; Crystal; Electron; Hole state in a solid; Semiconductor; Solid-state physics; Valence band

The content above is only an excerpt.