Compound semiconductors

What is the empirical rule called that says the lattice constant of an alloy semiconductor such as AlGaAs varies almost linearly with composition?

  1. AMoore's law
  2. BVegard's law
  3. COhm's law
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Answer: B. Vegard's law

Vegard's law is the empirical rule that an alloy's lattice constant equals a linear interpolation of its constituents' lattice constants according to composition. It is used, for example, to find compositions that lattice-match a substrate. In reality there are small deviations (bowing), and the band gap in particular often departs from a straight line.

  • A. Moore's law concerns increases in integration density.
  • B. Correct. It states that an alloy's lattice constant varies in proportion to composition.
  • C. Ohm's law relates voltage, current and resistance.
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