Semiconductor physics

Which value is closest to the energy of a single photon of light with a wavelength of 620 nm? (E [eV] ≈ 1240 / λ [nm])

  1. AAbout 1.0 eV
  2. BAbout 3.0 eV
  3. CAbout 2.0 eV
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Answer: C. About 2.0 eV

The photon energy is E = hc/λ, which in eV and nm becomes E ≈ 1240/λ. Substituting λ = 620 nm gives E ≈ 2.0 eV. If this energy is larger than the band gap, the semiconductor can absorb the light.

  • A. About 1.0 eV is the energy of light at about 1240 nm.
  • B. About 3.0 eV is the energy of light at about 413 nm.
  • C. Correct. 1240 ÷ 620 ≈ 2.0 eV.
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  2. Which is the correct definition of the work function of a material?
  3. Which value is closest to the relative permittivity of silicon?
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