Schottky barrier

A Schottky barrier is an energy barrier for charge carriers at a metal–semiconductor interface. Its height and electrical behavior depend on the materials and interface conditions.

Schottky–Mott rule: A model that estimates a metal–semiconductor barrier height from the metal work function and semiconductor electron affinity. It gives the ideal work-function-based prediction for the barrier.
Work function: The energy required to remove an electron from a material’s Fermi level to the vacuum level. The metal work function enters the ideal estimate of contact barrier height.
Schottky diode: A diode whose rectifying junction is formed by a metal–semiconductor contact. It uses the barrier’s asymmetric current response to rectify electrical signals.
p–n junction: A semiconductor junction between regions with opposite types of majority carriers. Its rectification arises from a semiconductor–semiconductor junction rather than a metal contact.
Fermi-level pinning: The tendency of a semiconductor’s interface Fermi level to remain near a particular energy despite changes in the contacting material. Pinning explains why measured barrier heights often depart from Schottky–Mott predictions.
Electron affinity: The energy difference between a semiconductor’s conduction-band edge and the vacuum level. It sets the semiconductor reference energy in ideal band-alignment calculations.
Schottky transistor: A transistor that uses a Schottky contact as a gate or carrier-injection junction. Its contact barrier can control injection or the transistor’s operating characteristics.
Bardeen model: A model in which interface states pin the semiconductor Fermi level and strongly influence contact barriers. It contrasts with the ideal Schottky–Mott picture by emphasizing interface-state control.
Image-force barrier lowering: A reduction in a charge carrier’s potential-energy barrier caused by its electrostatic attraction to its induced image charge. The electric field at a biased contact lowers the effective barrier.
Fermi level: The electron chemical potential that determines occupation probabilities of electronic states in a material. Equilibrium requires the Fermi level to align across the metal and semiconductor.

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