Schottky barrier (rus. барьер Шоттки otherwise барьер Шотки) — potential barrier formed at the metal-semiconductor junction and equal to the difference in the work functions (energy needed to remove an electron from a solid or a liquid into a vacuum) of the metal and the semiconductor: .

Description

Named after W. Schottky, the German scientist who studied such barriers in 1939. For a potential barrier to form it is necessary for the work functions of the metal and the semiconductor to be different. When a -type semiconductor approaches a metal, whose work function j is greater than that of the semiconductor, the metal becomes negatively charged, and the semiconductor positively charged, and the electrons move more easily from the semiconductor to the metal and back. On the contrary, when a -type semiconductor approaches a metal, whose work function j is lower than that of the semiconductor, the metal becomes positively charged, and the semiconductor negatively charged. The contact potential difference occurs in establishing the equilibrium between the metal and the semiconductor: ( is an electron charge). The high conductivity of the metal does not allow the electric field to penetrate into it, and the potential difference occurs in the surface layer of the semiconductor. The direction of the electric field in this layer is such that the energy of the main charge carriers in it is higher than in the bulk of the semiconductor. As a result, a potential barrier occurs in the semiconductor near the contact with the metal at for  - type semiconductor for -type semiconductor.

In real metal-semiconductor structures the ratio is not satisfied, as local electronic states are usually present on the surface of the semiconductor or in the thin dielectric interlayer.

The Schottky barrier has rectifying properties. Under the influence of an external electric field the current passing through the barrier is created almost entirely by the main current carriers. The metal - semiconductor junctions with Schottky barriers are widely used in microwave detectors, transistors and photodiodes.

Author

  • Goldt Ilya V.

Sources

  1. Schottky barrier // Physical encyclopedia (in Russian). V. 5 Ed. by A.M. Prokhorov. — Moscow: Sovetskaja ehnciklopedija, 1988. P. 467.
  2. Semiconductor convertors // Nanometr (in Russian), 2009. — www.nanometer.ru/2009/04/08/preobrazovatel_barer_shottki_diod_shottki_153822.html (reference date: 12.12.2011).

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