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Phonon‐Assisted Two‐Photon Exciton Transitions in Semiconductors
Author(s) -
Hassan A. R.
Publication year - 1988
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.2221470123
Subject(s) - exciton , semiconductor , degeneracy (biology) , condensed matter physics , phonon , valence (chemistry) , attenuation coefficient , band gap , valence band , direct and indirect band gaps , absorption (acoustics) , photon , physics , multiple exciton generation , quantum mechanics , optics , bioinformatics , biology
Phonon‐assisted two‐photon transitions to excitonic states in semiconductors are theoretically investigated. The effects of both, the nonparabolicity of the band and the degeneracy of the valence band are taken into account. Expressions for the absorption coefficient through different band models are calculated. The numerical applications to CdI 2 and GaP show that the four‐band model gives the dominant contribution which leads to a final s‐exciton state. An exciton peak appears at an energy which is close to that recently observed in CdI 2 . The non‐parabolic effect enhances the absorption coefficient by a two‐order of magnitude.