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Quantum Theory of Free Carrier Absorption
Author(s) -
von Baltz R.,
Escher W.
Publication year - 1972
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220510209
Subject(s) - physics , photon , degenerate energy levels , scattering , condensed matter physics , electron , absorption (acoustics) , free carrier absorption , free electron model , fermi energy , photon energy , plasmon , drude model , phonon , atomic physics , fermi's golden rule , scattering theory , semiconductor , quantum mechanics , fermi gamma ray space telescope , optics
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.