PN junctions and diodes

Which is a characteristic of a Schottky barrier diode?

  1. AIt is a diode made by joining two p-type semiconductors
  2. BIt uses a metal-semiconductor junction, with a low forward voltage and fast switching
  3. CIt emits strong light when forward current flows
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Answer: B. It uses a metal-semiconductor junction, with a low forward voltage and fast switching

A Schottky barrier diode uses a metal-semiconductor junction (Schottky junction). It operates with majority carriers only and has no minority-carrier storage, so its reverse recovery time is short and it is fast. Its forward voltage is also lower than that of a PN junction diode, so it is used in switching power supplies and similar circuits.

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More PN junctions and diodes questions

  1. Which property does a variable-capacitance (varactor) diode use?
  2. In a PN junction where the p side is far more heavily doped than the n side (a p+n junction), how does the depletion layer spread?
  3. Why does a reverse current flow briefly (a reverse recovery time exists) when a PN junction diode is switched from forward to reverse?
  4. How does the built-in (diffusion) potential of a PN junction relate to the doping on each side?
  5. Which correctly describes the mechanism of avalanche breakdown?