Quantum Theory of Free Carrier Absorption

✍ Scribed by R. von Baltz; W. Escher

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 465 KB
• Volume: 51
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2220510209

✦ Synopsis

Abstract

The theory of photon absorption by free carriers in degenerate semiconductors is given taking into account the influence of nonparabolic energy bands and the effects of scattering by impurities, phonons, and plasmons. Analytical formulas for the imaginary part of the dielectric function, ϵ~2~(ω), are derived. The quality of the asymptotic expansions of ϵ~2~(ω) for low and high photon energies to approximate ϵ~2~(ω) over a wide range of frequencies is investigated numerically. It is found that within a few percent the classical Drude theory gives an excellent approximation for photon energies up to twice the Fermi energy of the electrons. In the opposite case, the approximation for high photon energies gives a rather poor approximation of ϵ~2~(ω) near the Fermi energy, except for ionized impurity scattering.