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Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an n-type semiconductor, the density of electrons is 10¹⁹ m⁻³ and their mobility is 1.6 m²/(V·s) then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to:
- 2Ωm
- 4Ωm
- 0.4Ωm
- 0.2Ωm
Correct answer: 0.4Ωm
Solution
The resistivity of a semiconductor can be calculated using the formula ρ = (1)/(q n μ), where q is the charge of an electron (approximately 1.6 × 10⁻¹⁹ C), n is the electron density, and μ is the mobility. Substituting the given values, we find that the resistivity is approximately 0.4 Ωm, confirming that option C is correct.
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